Introduction to ArcGIS I

Transcription

1 Introduction 1-1

2 What is ArcGIS? ArcGIS Clients ArcReader E X T E N S I O N S ArcGIS Desktop ArcView ArcEditor ArcInfo ArcGIS Engine ArcPad Custom Application E X T E N S I O N S Web Browser Components ArcObjects Network ArcGIS Server ArcIMS Application/Data Servers ArcSDE RDBMS 1-2 ArcGIS is the name used to identify ESRI s flagship family of GIS products. ArcGIS includes ArcGIS client software, components as well as application and data server software. ArcGIS itself is not a GIS application; rather, it is a set of software products for building ArcGIS systems that best suit your GIS needs. ArcGIS is based on a common library of shared GIS software components, called ArcObjects. ArcGIS is composed of client and server applications. Each software application can create, manage, analyze, and serve data stored in one or more formats. ArcGIS Desktop: Integrated suite of advanced GIS applications consisting of three software products: ArcView, ArcEditor, and ArcInfo. The ArcGIS Desktop applications provide the same core mapping, editing, and analysis functionality. The level of functionality available differs depending on which license you have. ArcInfo provides users with the most complete level of GIS functionality. It is composed of ArcInfo Desktop, as well as ArcInfo Workstation. ArcReader : Allows users to view high quality published maps (.PMFs) created in ArcMap. ArcGIS Engine: Developer toolkit of embeddable GIS components for building custom stand alone applications using COM, C++, Java, and.net ArcPad : Used with PDAs for creating and managing data while in the field ArcGIS Server: A shared library of GIS software objects used to build/develop serverside GIS applications in enterprise and Web computing frameworks ArcIMS : Use to publish maps, data, and metadata through open internet protocols ArcSDE : Manages and serves spatial information from external RDBMS to ArcGIS clients For more information, go to Introduction 1-2

3 ArcGIS Desktop Products Tools and database functionalities vary between ArcGIS products ArcView ArcEditor ArcInfo M o r e F u n c t i o n a l i t y 1-3 The ArcGIS Desktop includes a suite of integrated applications: ArcMap, ArcCatalog, and ArcToolbox and Geoprocessor interfaces. Using these applications together, you can perform any GIS task, simple to advanced, including mapping, data management, geographic analysis, data editing, and geoprocessing. In addition, ArcGIS allows you to tap in to an abundance of spatial data and resources available through ArcIMS services on the Internet or stored in an ArcSDE database. The ArcGIS Desktop is a comprehensive, integrated, scalable system designed to meet the needs of a wide range of GIS users. The ArcGIS Desktop can be accessed using three software products, each providing a higher level of functionality. ArcView provides comprehensive mapping and analysis tools along with simple editing and geoprocessing tools. ArcEditor includes the full functionality of ArcView, plus advanced editing capabilities. ArcInfo extends the functionality of both to include advanced geoprocessing and also includes the applications for ArcInfo Workstation (Arc, ARCPLOT, ARCEDIT, and so on). Because the ArcGIS products all share a common architecture, users working with any of these clients can share their work with other users. Maps, data, symbology, map layers, custom tools and interfaces, reports, metadata, and so on, can be accessed interchangeably in all three products. Much more information about the entire ESRI product line can be found at Introduction 1-3

4 Overview of applications All ArcGIS products share common applications ArcMap, ArcCatalog ArcToolbox and Command Line windows 1-4 All ArcGIS products (ArcView, ArcEditor, and ArcInfo) are comprised of the ArcMap and ArcCatalog applications, both of which contain the Toolbox and Geoprocessing windows. ArcMap is the application for performing analysis and making maps. ArcCatalog is a tool for accessing and managing your data. ArcToolbox contains tools for data conversion and management. The Geoprocessing window allows you to write, import and run scripts, and access individual commands. Introduction 1-4

5 ArcMap Primary display application Perform map-based tasks Displaying Editing Querying Analyzing Charting Reporting 1-5 ArcMap provides tools for creating visual displays of your data, querying, and creating presentation-quality maps. ArcMap makes it easy to lay out your maps for printing, embedding in other documents, or electronic publishing. It also includes analysis, charting, reporting functions, and a comprehensive suite of editing tools for creating and editing geographic data. When you save a map, all of your layout work, symbols, text, and graphics are automatically preserved. ArcMap is the primary ArcGIS application for displaying, querying, editing, creating, and analyzing data. Introduction 1-5

6 ArcCatalog A window into your database Browse your data Manage your data Create and view data documentation (metadata) 1-6 The ArcCatalog application helps you organize and manage all your GIS data. It includes tools for browsing and finding geographic information, recording and viewing metadata, quickly viewing any dataset, and defining the schema structure for your geographic data layers. Introduction 1-6

7 ArcToolbox Window Available in ArcCatalog and ArcMap Geographic processing functions Data management, analysis, and conversion Tools vary between ArcGIS products 1-7 The ArcToolbox window provides you with tools for data conversion, managing coordinate systems, changing map projections, and more. ArcToolbox supports easy-to-use drag-and-drop operations from ArcCatalog; with ArcMap, you need to browse to or type in the variables. For ArcInfo users, ArcToolbox provides additional and more sophisticated data conversion and spatial analysis tools. Introduction 1-7

8 Getting help Tabs Contents Index Search Favorites Other help What s this? Tool tips Online Support 1-8 The ArcGIS Desktop Help provides several methods for finding the help you need to use the software most productively. The Contents tab lets you search for information by topic. The Index tab lets you search for topics containing words from the Help index, such as Layer or Table. The Search tab lets you search the Help document for a word you specify. The Favorites tab lets you store your favorite help topics so you can easily access them when needed. Your word does not have to be in the index in order to search the document for it, but the search will take longer if it is not in the index. In ArcCatalog, ArcMap, and ArcToolbox, button and tool names are displayed when you move the mouse over them (these are called ToolTips). You can also click the What s This? tool in ArcMap or ArcCatalog and then click on a button or tool to access additional help about it (this is called context-sensitive help). For applications like ArcMap that have graphical user interfaces, context-sensitive help is useful for finding out what all the various buttons and tools do. Selecting the ESRI Support Center link will connect you with a wealth of additional online resources. The Web site URL is Introduction 1-8

9 Displaying data Introduction 1-9

10 Lesson 2 overview The ArcMap interface and tools Data View and Layout View Layers, data frames, and map elements Layer properties for symbols and labels 1-10 Introduction 1-10

11 The ArcMap interface Title bar Menu bar Standard toolbar Table of Contents Dockable Display area area Context menu Tools toolbar Tear-off and and dockable Draw toolbar Status bar 1-11 Features of the ArcMap interface The Title bar displays the map name (EuropeOnly.mxd in the example above). The toolbars are dockable. The Table of Contents lists the Data Views and layer legends. The Table of Contents is dockable and can be resized by horizontally dragging the vertical divider between the Table of Contents and the display area. The display area is where the map features draw. The Status bar, besides reporting the coordinates, displays a description of the selected buttons and menu items. Introduction 1-11

12 Data View or Layout View? Data View For display, queries, editing, and analysis Layout View For creating map layouts Data Data View View Layout Layout View View 1-12 Data View You will work in Data View if you want to display, query, edit, explore, and analyze data. Layout View When you choose to create a hard copy map, you need to move to the Layout View. This view is where you add all the other map elements, such as the north arrow, legend, scale, title, and other textual information (e.g., author, data date, map date, projection type). Once the map is complete, you can send it to a plotter or printer or export it as a graphic file. Introduction 1-12

13 Layers, data frames, and maps Layer Represent symbolized spatial data Data frame Organizes layers Map contains Data Data frame Data frames Layers Layers Map elements 1-13 Layers, data frames, and maps Layers store the path to a data source as well as the display properties of that data source. A data frame is a container for layers. When you create a new empty map, a default data frame named Layers is automatically added to the top of the Table of Contents, but you can highlight and change its name. In the example above, the data frame name was changed to Europe. Like the layers they contain, data frames also have properties that you can manipulate. A map is the document that stores the data frames, layers, and any map elements such as graphics and text. A map may contain several data frames. For example, you might create a map that contains one data frame with layers that show an entire country and another data frame that displays layers of a particular region. Introduction 1-13

14 Layers Reference spatial data sources Set symbols, labels, and other properties Manipulate through context menu 1-14 Layers A layer does not store the actual geographic data but instead references the data contained in the data source. Data sources can be any of the following: Vector datasets (feature layers): Coverages, shapefiles, CAD files, geodatabase, and ArcSDE databases Annotation and Dimensions Raster datasets (raster layers): Grids and images TIN datasets: Triangulated Irregular Networks these model 3D data Referencing data in this way allows the layers on a map to automatically reflect the most up-todate information in your GIS database. Layers are stored as part of a saved map document (.mxd file), but they can also be saved as independent files themselves. Layer files (.lyr files) are an efficient method of predefining symbology and other properties, allowing you to set and share standard display options for specific data sources. Introduction 1-14

15 Data frames Data frames are containers for layers Maps can have many data frames Index and inset maps Arrange in Layout View Add from Insert menu Activate data frames to view from context menu 1-15 Data frames Data frames let you organize your data into logical groupings, such as themes or geographic areas. You may want to consider using multiple data frames when you want to compare layers side by side or create insets and overviews that highlight a particular location. You can add as many layers as you want to a data frame; however, a data frame containing too many layers can be more difficult to work with. You may want to consider multiple data frames organized by theme or geography when you have numerous layers. When a map has more than one data frame, one of them is the active data frame. The active data frame is the one you are currently working with in the ArcMap display. For example, when you add a new layer to a map, it gets added to the active data frame. You can always tell which data frame is active because its name is shown in bold text in the Table of Contents. Of course, if a map has only one data frame, it is always the active one. To make a data frame active, right-click on the data frame and click Activate. The active data frame appears in bold font in the Table of Contents. A data frame can also be activated in the Layout View when you use your mouse to select it from the page. Introduction 1-15

16 Maps Hold layers, data frames, graphics, map elements Store information in a map document (MXD) file 1-16 Maps The ArcMap document helps you visualize geographic information by showing you the location of features, which are symbolized to help you understand what they are and why they are being shown. A map can include additional information, such as graphics and map elements, that help explain its context and purpose. When you open a map document, ArcMap checks the links to the data sources. If it cannot find some data (i.e., if the source data for a layer has been deleted or renamed or if a network drive is not accessible), it does not display. The layer is still part of the map, and its name appears in the Table of Contents, but a small red exclamation mark appears right of the layer symbol. When you work in ArcMap, you are always working within an ArcMap document. The ArcMap document (MXD) lets you save the display of your data. Introduction 1-16

17 Managing the Table of Contents (TOC) Drag layers up or down to change display order Smart defaults for layer draw order Point, lines, or polygons Layers draw in the TOC in order From the bottom up Rename data frames and layers Remove layers Bottom tabs Display Source 1-17 Managing the Table of Contents The Table of Contents lists all the data frames and thematic layers on the map and shows the symbols used to represent the features in each layer. A check box next to a layer indicates whether it is currently visible on the map. Layers at the top of the Table of Contents draw on top of layers listed below them. Learning how to manage layers and frames within the Table of Contents helps you represent your data effectively and efficiently. The draw order of layers within a data frame is from the bottom to the top, so you put those layers that form the background of your map, such as the ocean, at the bottom of the Table of Contents. ArcMap is smart enough to display a point feature class on top of a polygon feature class. To change the order of display, click the layer and drag it up or down the Table of Contents to a new location. You can copy and paste layers within the same data frame or into a different data frame. Layers can be removed by right-clicking on the layer and clicking Remove from the context menu. Introduction 1-17

18 Moving around the map Zoom in or out Pan the display Full extents Back or forward one display Zoom to a layer Zoom to selected features 1-18 Moving around the map As you work with a map, you can easily change how you view the data it contains. When you are just browsing a map, you might want to pan and zoom around the data to investigate different areas and features. When you are creating a map to use in the field, displaying data at a specific scale may be important in order to keep ground measurement computations simple. Most of the tools for navigating your data are found on the Tools toolbar; others are located on the layer context menus. Introduction 1-18

19 Using a bookmark Spatial bookmarks Set and name spatial extent Return to it at any time Data frame specific 1-19 Using a bookmark A spatial bookmark identifies a particular geographic extent that you want to save and refer to later. For example, you might create a spatial bookmark that identifies a study area. As you pan and zoom around your map, you can easily return to the study area by accessing the bookmark. You can also use spatial bookmarks to highlight areas on your map you want others to see. You can create a spatial bookmark at any time. As a shortcut, you can also create bookmarks when you find and identify map features. Spatial bookmarks, however, can only be defined on spatial data; they cannot be defined on an area of the page in Layout View. Each data frame on your map maintains its own list of bookmarks. In Layout View, the list reflects the bookmarks of the active data frame. Introduction 1-19

20 Magnifier and overview windows See more detail or overview without changing display Shows full extent of data plus extent of Data View Move over display like a magnifying glass 1-20 Magnifier and overview windows When you do not want to adjust your map display, but you want to see more detail or get an overview of an area, open another window. ArcMap provides two additional ways to explore the spatial data on your map: an overview window and a magnifier window. The magnifier window works like a magnifying glass; as you pass the window over the data, you see a magnified view of the location under the window. Moving the window around does not affect the current map display. The overview window shows you the full extent of the data. A small box in the overview window represents the currently displayed area on the map. You can move this box around to pan the map and shrink or enlarge it to zoom in or out. Both windows operate only in Data View. Introduction 1-20

21 Labeling features Label features dynamically using attribute values Layer properties control appearance and position Convert labels to annotation features 1-21 Labeling features When you label features on a map, readers can quickly identify them and more easily interpret the map. In ArcMap, you can label features using their attributes or by entering text on the map interactively. Choosing which features are labeled, where the labels are placed, and setting the label display scale can impact whether the right information is conveyed to the reader and can affect the overall legibility of the map. The graphic characteristics of a label symbol can impact the legibility of your text and imply specific meanings. For instance, hydrologic features are typically labeled with blue italicized text. ArcMap gives you significant choice and control over the label symbols you use. Where you place text labels depends on the text font, text size, text position, map scale, and the number of features that need to be labeled. To help you with this task, ArcMap provides tools for controlling the placement, size, map scale, and many other qualities of label text. Labels and the parameters you set for their display are stored within the layer properties and are only available when you add the layer to your ArcMap session. In addition, labels may dynamically shift position as you change your Data View (i.e., zoom in and out or pan), in order to achieve a best fit based on any conflict rules you may have set. Annotation Unlike labels, annotation is stored as a new layer or feature class in ArcGIS. When you create annotation, you have the option of storing the layer within the map document or as a new feature class in the geodatabase. Once created, annotation features do not move dynamically in the display when you move around the map but remain in a fixed location. In addition, converting labels to annotation allows you to control the placement and/or change the font type for each individual text element. Introduction 1-21

22 Changing symbol properties Symbology tab or Table of Contents Left-click Right-click 1-22 Changing symbol properties ArcMap makes it easy to change both a layer s symbol color (right-click on the symbol) or the symbol itself (click on the symbol). Although ArcMap allows you to choose many symbols and colors, it is important to remember that too many symbols or colors in a map can be distracting. The symbology you choose for displaying layers greatly affects how readers interpret the map. Learning how to display your layers clearly and efficiently helps your audience understand your data and may also reveal patterns not otherwise apparent. Introduction 1-22

23 Scale-dependent display Display layers at specific scale range Reduces clutter Reduces drawing time Layer display property 1 : 25,000,000 1 : 5,000,000 1 : 500, Scale-dependent display For each layer in your map, you can set a scale range at which ArcMap displays that layer. Setting a display scale lets you avoid needless clutter on your map by restricting the display of features until an appropriate scale is reached one with information that is useful to the reader. Two methods are available for setting the scale range: Use the Zoom tools to interactively set the display to the minimum scale to which the layer will be drawn. Right-click on the layer and click Visible Scale Range > Set Minimum Scale. Adjust the display scale and repeat to set the Maximum Scale. Right-click the layer; then click Properties. On the Properties dialog, click the General tab and set the scale range as shown in the figure above. You can set a layer s properties so that its features display only if the map extent falls within a certain scale range. The Table of Contents shows a grayed-out check box when the map is outside the scale range for that layer. Introduction 1-23

24 Creating a definition query Build a query based on attributes Only displays queried features Does not affect source 1-24 Definition queries Definition queries can be used to select specific features within a layer, and they only display items that satisfy the condition. Queries are defined under the Definition Query tab in the Layer Properties dialog; simply click the Query Builder button to write a query. After applying the built query string, only the features that meet the query criteria appear in the display area. Although only the features that satisfy the query are displayed, the source data remains intact and unchanged. The remaining features are just hidden from view. It is important to emphasize that this is different than a selection in ArcMap (whether spatial or attribute) where all features in the layer remain displayed, except that the selected features appear selected with blue outlines. Introduction 1-24

25 Layer symbology in ArcMap Same symbol for all features Based on attribute values Thematic classification methods 1-25 Layer symbology in ArcMap Drawing properties can be set within the Symbology tab of the layer s Layer Properties dialog. In the Show panel of the Symbology tab, ArcMap has several options for creating both qualitative and quantitative thematic maps. When you chose a certain method, the properties options to the right of the Show panel change according to the type of thematic mapping method used. Introduction 1-25

26 Displaying qualitative values Features Categories 1-26 Display qualitative values Often, seeing where something is and where it is not can tell you exactly what you need to know. Mapping the location of features reveals patterns and trends that can help you make better decisions. The easiest way to see where features are is to draw them using a single symbol. You can draw any type of data this way. When you create a new layer, ArcMap draws it with a single symbol by default. A category describes a set of features with the same attribute value. For example, given parcel data with an attribute describing land use (e.g., residential, commercial, and public areas), you can use a different symbol to represent each unique landuse type. Drawing features this way allows you to see where features are and what category they belong to. This can be useful if you are targeting a specific type of feature for some action or policy. For instance, a city planner might use the landuse map to target areas for redevelopment. In general, look for these kinds of attributes when mapping by category or unique value: Attributes describing the name, type, or condition of a feature Attributes containing measurements or quantities that are already grouped (e.g., 0 99 or ) Attributes that uniquely identify features (e.g., a county name attribute could be used to draw each county with a unique color) You can let ArcMap assign a symbol to each unique value based on a color scheme you choose, or you can explicitly assign a specific symbol to a specific attribute value. Introduction 1-26

27 Displaying quantitative values Quantities Charts 1-27 Display quantitative values When you want your map to communicate how much of something there is, you need to draw features using a quantitative measure. This measure might be a count, a ratio (such as a percentage), or a rank (such as high, medium, or low). You can represent quantities on a map by varying the color or symbol size you use to draw features. For example, you might use increasingly darker shades of blue to represent increasingly higher rainfall amounts or larger circles to represent cities with larger populations. Generally, you need to classify your data when you display it. You can either manually define classes or apply one of the standard classification schemes to do so automatically just specify the number of classes you want to show. Once you have defined the classes, you can add more classes, delete classes, or redefine class ranges. Pie charts, bar charts, and stacked bar charts can present large amounts of quantitative data in an eye-catching fashion. For example, if you are mapping population by county, you can use a pie chart to show the percentage of the population by ethnic group for each county. Generally, you will draw a layer with charts when your layer has a number of related numeric attributes that you want to compare. Use pie charts if you want to show how much of the total amount each category takes up. Use bar charts to show relative amounts rather than a proportion of a total. Introduction 1-27

28 Saving a layer file Save symbology for use in other map documents Layer files.lyr extension Save the display for a layer without saving an entire map document Load into another map document Preview in ArcCatalog Default Customize Sources symbology symbology In In map map document (.mxd) (.mxd) Vector Raster Save TIN As As a separate layer layer (.lyr) (.lyr) 1-28 Saving a layer file It takes time to analyze a data s attributes and symbolize its features so people will readily understand the information within the data. Layers you create in ArcMap are stored as part of the map document file. After finalizing the symbolization and labeling of a layer, you can save it outside the map as a layer file. This layer file can be reused in other maps, or you can it along with the data to people, who want to add it to their maps. How to save a layer outside a map 1. In ArcMap, open the map containing the layer that you want to save as a layer file. 2. Right-click the layer in the map s Table of Contents. 3. Click Save As Layer File. 4. Navigate to the folder in which you want to save the layer. 5. Type a name for the layer file. 6. Click Save. Introduction 1-28

29 Changing the data source for a layer Map documents can lose track of the source data Source data gets moved or renamed Use Source tab to change the data source for a layer Shortcut: Right-click the layer > Data > Set Data Source Layers with misplaced source data Click here to change the data source 1-29 Changing the data source for a layer The map document does not store the spatial data displayed in it; instead it stores references to the locations of the data sources. When a map document is opened, ArcMap reads the file and looks for all the path names to reconstruct the layers. When data sources are moved or renamed, map documents can lose track of the source data for its layers. When this occurs, the layer name appears in the ArcMap Table Of Contents with a red exclamation mark, and nothing appears for that layer in the display area. To correct this problem, access the Properties dialog for the missing layer. Click the Source tab, and click Set Data Source. This brings up a browser to specify the new location of the data. Once done, the path to the data source is fixed, and the layer appears. Remember to save the map document so that the new path is saved as well. There is also a shortcut to help correct the path name for a data source. Right-click the layer, click Data in the context menu, and then click Set Data Source from the second context menu. Introduction 1-29

30 Setting ArcMap options Control default behaviors Application startup screens When resizing window Table fonts Layout rulers and grid spacing Raster display DGN compliance for CAD files Table of Contents appearance Geoprocessing environment settings 1-30 Setting ArcMap Options You can adjust a number of default settings for ArcMap behaviors. For example, you might change the text size and font of your tables so that they are easier to read. You might also want to change the shape of the lines and patches that represent the features on a map in your Table of Contents. As shown on the slide above, you can add an additional tab to the bottom of your Table of Contents; the Selection Tab provides you with another method of turning selectable layers on or off (see also slide 4-10). Other settings include: Layout View: Setting snapping to grids or guides, turning on/off rulers and scroll bars Raster: Set default display colors for different bands from a wide variety of raster formats (particularly useful for remotely sensed or false color imagery) Geoprocessing: Set default disk storage locations or spatial reference for new data You access these options through the Tools menu > Options, located at the bottom of the list. Introduction 1-30

31 Querying your database Introduction 1-31

32 Lesson 3 overview Tools for examining your data Identify, Find, Measure, MapTips, hyperlinks Working with the selection tools Why do you need a selection? Available selection tools Selection methods and layers Spatial selection Attribute selection Calculating summary statistics 1-32 Introduction 1-32

33 Identifying Popup attributes for a specific feature i 1-33 Identify Features tool This tool allows you to display the attributes for any feature you click on with your pointer. Introduction 1-33

34 Finding Locate a specific feature or attribute France flashes 1-34 Find button Clicking this button brings up the Find window on the screen. Type in the string that you want to search for. Notice that you can search in all the layers in your map or just in a specific layer. You can also choose to search all the fields (attributes), specific fields, or each layer s primary field for the occurrence of the string you typed earlier. The string can be typed in lowercase, uppercase, or a combination of both. After the search is over, the window expands to reveal the findings. You get the layer(s) and the field(s) in which the string was found in the feature attribute table(s). If you right-click the value, a context menu appears with options to flash the feature, zoom to it, identify it, set a bookmark, and select or unselect the feature. Introduction 1-34

35 Measuring Find linear distances 1-35 Measure tool Use the Measure tool to find distances on the map. The Measure tool allows you to draw a line on the map using your mouse. To start, click at a location, and as you move your mouse, a thick line appears on the map. A single-click adds a line segment, while a double-click ends the line. The status bar reports the length of each segment as it is created and the total length of the line when you are finished. All measurements use a pure Cartesian coordinate system, so use such measurement results with caution. You should expect some inaccuracy due to various factors when using this tool for small-scale measurements. Introduction 1-35

36 MapTips and hyperlinks Display property of a layer MapTips Pointer location displays specific attribute Hyperlinks Document URL Macro Multiple links per feature 1-36 MapTips and hyperlinks If you have MapTips set for a layer, when you move the mouse pointer over a feature in the layer, a rectangular box containing textual information appears. The MapTip text comes from a field in the attribute table of that layer. You have to set which field you want attribute values to be reported from when using the MapTips. You can display Web pages accessed over the Internet and documents (such as a text file or image) or run a macro (script). You can dynamically create hyperlinks as you browse your map, or you can store hyperlinks with your data in an attribute field. When you click on a feature, ArcMap determines which program is needed to display the hyperlink. If you specify a Web address, ArcMap launches your default Web browser and displays the page. If you specify a different type of document (e.g., a text document), ArcMap displays it using its native program (such as Notepad or another text editor). The Hyperlink Manager allows you to set more than one hyperlink per feature; these are called Dynamic Hyperlinks. If you are creating maps that people will access interactively or if you want to explore your data before you do analysis, MapTips and hyperlinks are useful ways to present more information about the map s features. Introduction 1-36

37 Why do you need a selection? Focused analysis Use to to select other features Edit Selected features Create a new layer Calculate statistics Report Export Convert to to graphics 1-37 Why do you need a selection? You may have several reasons why you would make a selection, including: Using the selected set for further analysis Using the selected set to select other features Editing the selected set Creating a new layer from the selected set (Working with a subset is faster than including the entire set.) Calculating statistics for the selected set Creating a report Exporting the selected set to a separate file Converting features to a graphic format Introduction 1-37

38 Available selection tools Interactive, attributes, location, graphics Selected set set 1-38 Available selection tools There are four ways to select graphics in ArcMap: interactively, by attribute, by location, and by graphics. Interactive selection method This option offers different selection methods, including create a new selection, add to current selection, remove from current selection, and select from current selection. Options further refine the interactive selection methods, which include selecting features that are spatially or completely within the box or graphic, selecting features that are completely within the box or graphic, and selecting features that the box or graphic are completely within. Select by attributes With this option, you can write a selection statement. The search is done on the records in the feature attribute table based on the selection criteria typed in the selection statement. Because all features are linked to their respective records in the feature attribute table, ArcMap is able to select the features based on their attributes. Select by location Here, features from a certain layer can be selected by features from another. This is considered a spatial query tool. Select by graphics Features are selected based on their relationship to a graphic or graphics you create through the Draw toolbar (e.g., a polygon or line). The same selection options apply when you select by graphics as when you use the interactive selection method. Other features in this selection menu include controlling which layers are considered in the selection, zooming to the selected features, and clearing the selection. Introduction 1-38

39 Selection layers Specify from Selection menu or add tab to TOC Layers available when using interactive selection tool Method 1 Method Set Selectable Layers While making spatial selections, you have the option of turning on or off the layers that are going to be involved in the selection operation. This can be done in two ways: Method 1 From the Selection menu, click Set Selectable Layers. Check the check boxes for any layers you want to include in your next selection. Method 2 From the Tools menu, click Options and click on the Table of Contents tab. Check the Selection check box in the Table of Contents tab options panel and then click OK. Now you have a permanent Selection tab at the bottom of ArcMap s Table of Contents. When you click this tab, a list of layers with check boxes to their left appears. Now you can check which layers should or should not be included in your next selection. Introduction 1-39

40 Selection methods Specify from Selection menu Create new selection Add to the selection Remove from the selection Select from selection 1-40 Interactive selection method Four methods are available: Create New Selection All features are available at the onset, and you select four countries: France, Poland, Bulgaria, and Greece. Add to Current Selection Now you want to add more countries to the first four selected. You select Denmark and Italy. Remove From Current Selection Here, you decide to remove Bulgaria and Greece from the current selection. Select from Current Selection This time you decide to select only France from the current selection. Introduction 1-40

41 Interactive selection options Options from Selection menu Select features partially or completely within the box or graphic(s) Select features completely within the box or graphic(s) Select features that the box or graphic are completely within 1-41 Interactive selection options The Selection dropdown list offers three additional selection options depending on how you want the features to be selected when you create a selection box: 1. Select features partially or completely within the box or graphic: Complete features are selected, whether they fall completely within the selection box or fall partially within the selection box. 2. Select features completely within the box or graphic: Complete features are selected only if they fall completely within the selection box. 3. Select features that the box or graphic are completely within: The selection box must fall completely within the feature to get selected. This technique is useful if the selected feature is multipart or an irregular shape. Introduction 1-41

42 Attribute selection Use a SQL where clause to select features Save and reload selection expressions For current selection: Add to Remove from Select from Field Operator Value 1-42 Attribute selection ArcMap lets you select features using a where clause from Structured Query Language (SQL) in the Selection menu s Select By Attributes dialog. SQL is a powerful language you use to define one or more criteria by which you want to select features or rows. You define the criteria by creating expressions consisting of attributes, operators, and values. For example, imagine you have a customer database, and you want to find those customers who spent more than $50,000 last year and whose business type is Restaurant. You could select the customers with this expression: Sales > AND Business_type = 'Restaurant'. To create an attribute selection, you need to do the following: 1. From the Selection dropdown list, click Select By Attributes. 2. On the Select By Attribute window, choose the layer from which you want to select features. 3. Write a selection statement (otherwise known as an SQL statement). You can type this yourself, or you can create it by clicking a field and an operator button, followed by a value. You can also write more complicated expressions using connectors, such as And, Or, and so on. Clicking the Verify button helps you ensure that the syntax of the expression is correct. 4. When you are convinced the syntax is correct, click OK. You can build expressions to select features directly from your map or to select records from a table. Selecting records in an attribute table also highlights features in the map, so you can see where the associated features are. You can save selection expressions and reload them with the Save and Load buttons at the bottom of the Select By Attributes dialog. This saves time when you are working with complex query expressions. Simply load the expression back into the Select By Attributes dialog to easily regenerate a set of selected records. Introduction 1-42

43 Select by location (spatial query) Use features in one layer to select features in another Cities Countries Cities intersected by selected countries Result 1-43 Select by location (spatial query) You will often need to find features based on their geographic, or spatial, relationship to other features. Instead of using the cursor or geometric shapes to select features, you use features from one layer to select features in another layer. For this reason, Select By Location is called spatial query. When selecting features with spatial queries, you use the Select By Location dialog, available from ArcMap s Selection menu, to create a statement about what you want to select. Your selection procedures include: Select features from Add to the currently selected features Remove from the currently selected features Select from the currently selected features The selected features depend on the mode used. These modes are discussed on the next slide. Regardless of the mode you use, you have the option of narrowing your selection to a specific layer by checking off all the layers that you want to exclude. You can also select features using a certain buffer distance. You recall the introduction of the concept of topology in Lesson 2. The Select by Location dialog is where you can easily query your data using the topological relationships, which exist between features and layers. Introduction 1-43

44 Location selection methods Select by location offers many selection methods Intersect Contain Are contained by Share a line segment Counties Touch boundary Within a distance Are identical Are centered in More Pollution Result Polluted areas completely within selected counties Sightings River Result 2 km Animal sightings within a distance of 2 km from rivers 1-44 Location selection methods With the Select By Location dialog, you can select features based on their location relative to other features. Suppose you want to know how many homes were affected by a recent flood. Answering this question and others like it involves forming a spatial query. You want to find features based on where they are in relation to other features. For instance, if you mapped the flood boundary, you could then select all the homes that are within this area. By combining queries, you can perform more complex searches. For example, suppose you want to find all the customers who live within a 20-mile radius of your store and who made a recent purchase so you can send them a promotional mailing. You would first select the customers within this radius (select by location) and then refine the selection by finding those customers who have made a purchase within the last six months according to a date-of-lastpurchase attribute. You can use a variety of selection methods to select the point, line, or polygon features in one layer that are near or overlap the features in the same or another layer. Introduction 1-44

45 Select by graphics Draw a graphic to select features Works with interactive selection methods 1) Draw graphic 2) Select Method 1-45 Select by graphics You may use the tools on the Drawing toolbar to add graphics to the ArcMap display. For example, you may want to digitize a polygon around a group of islands that you want to select. Once the graphic has been added to the display, the Select by Graphics option is activated on the Selection menu. Introduction 1-45

46 Calculating summary statistics Select Features Layer Field 1-46 Calculating summary statistics After making a spatial or attribute selection, you may want to calculate a simple statistics summary. This can be done by clicking the Statistics option from the Selection dropdown list. This operation invokes the Selection Statistics dialog. Here you need to select the layer, as well as the field in the feature attribute table, that you want the statistics to be calculated for. Once these are selected, a numeric statistics summary, as well as a frequency distribution chart, appears in that window. Introduction 1-46

47 Working with spatial data Introduction 1-47

48 Lesson 4 overview Geographic data review Linking features and attributes Data formats Working with ArcCatalog Options Metadata 1-48 Introduction 1-48

49 Representing geographic features Vector X,Y X,Y X,Y X,Y X,Y X,Y X,Y Raster Column Row Data has Geometry Geometry Attributes Attributes Behavior Behavior rules rules 1-49 Representing geographic features The two basic models for digitally storing geographic data are vector and raster. The vector model uses discrete coordinates (commonly known as x,y coordinate pairs) to represent geographic features as points, lines, or polygons. The raster model uses equally sized square cells to represent features; the level of detail depends on the size of the cells. Each data model has pros and cons: vector data is cheap to store but expensive to process; raster data is cheap to process but expensive to store. Also, different physical phenomena may be more suited to one data type versus the other (e.g., rainfall is more suited to a raster data model, surveyed lines are more suited to the vector data model). GIS data is made up of three basic components: geography (the spatial representation of the features), attributes (the descriptive characteristics of the features), and behavior rules (instructions that govern what the features can and cannot do). Introduction 1-49

50 Introducing feature classes Collections of features with the same type of geometry Can create point, line, or area feature classes Many different line objects primary roads highways secondary roads Single linear feature class Roads 1-50 Introducing feature classes You know about point, line, and area abstraction. Given these choices, it would be impractical to store every line in its own dataset. Feature classes allow you to aggregate homogeneous features into a single collection. For example, highways, primary roads, and secondary roads can be grouped into a line feature class named Roads. All customers for each business franchise can be grouped into a point feature class named customers. Territories for homogeneous wildlife species can be grouped into a polygon feature class named habitat. The term feature class is used to refer to any grouping of points, lines, or polygons, regardless of the data storage format. What s a Layer? The word layer can be used generically to describe any individual (usually) horizontal stratum used to organize different logical groupings of spatial data. In ArcGIS, the word layer is used to describe a specific object or file used to symbolize a feature class. Refer to Lesson 3 to review. Introduction 1-50

51 Linking features and attributes Feature classes are tables that store spatial data Each feature has a record in the table Unique identifier links feature and attributes FID = 5052 Feature Identifier 1-51 Linking features and attributes For geographic objects stored in a feature class, each individual feature is assigned a unique numerical identifier and is characterized by a unique location in space and corresponding record in an attribute table. While the exact name of the numerical identifier may differ by the data format, it is important to understand this one-to-one relationship between feature, identifier, and attribute record. Introduction 1-51

52 Spatial data formats ArcGIS can work with spatial data in multiple formats Shapefile Coverage Geodatabase CAD CAD Internet Map Map Service Raster Raster Tables Tables ArcGIS ArcGIS 1-52 Spatial data formats Currently, there is not a standard format for GIS data. Various GIS software manufacturers and other organizations, such as government agencies, have continually searched for more efficient and versatile digital formats to store geographic information. ArcGIS has the advantage of seamlessly supporting all of the ESRI formats: shapefiles, coverages, GRIDs, the geodatabase, and data served over the Internet by ArcIMS. ArcGIS also supports the three most common CAD file formats (DXF, DWG, and DGN), as well as a variety of common image formats. Having the ability to work with so many different formats without needing to convert them is a tremendous advantage. More information describing all of the data types supported by ArcGIS can be found in the ArcGIS Desktop Help files by entering the keywords data types under the Index tab. Introduction 1-52

53 Geodatabase data format Stores spatial features and their attributes in the same RDBMS Feature datasets model spatial relationships Stand-alone feature classes RDBMS table Coffee point feature class Shape Shapefield accesses separate coordinate table table 1-53 Data format: Geodatabase In contrast to file-based formats like coverages and shapefiles, which store feature coordinate and attribute information in separate files, the geodatabase has the ability to store the two types of information in one database. This centralization of storage offers many advantages. Each geodatabase feature class can only store a single feature type, but you can easily group them into a feature class collection called a feature dataset as long as they have the same coordinate system. Note: The term geodatabase is used to refer to a storage format. You should be aware that ArcGIS supports two physical implementations of the geodatabase: a personal geodatabase and an ArcSDE geodatabase. The personal geodatabase is designed for smaller-scale projects and is stored in MDB format. You do not need to purchase any additional software programs to access and manage personal geodatabases. The ArcSDE geodatabase is designed for larger enterprise GIS applications and databases and is stored in one of the supported RDBMS formats (Oracle, SQL Server, DB2, Informix). These applications require you to purchase the supported RDBMS software for data storage. ArcGIS provides the necessary interface between your chosen RDBMS and the desktop applications. Regardless of the physical implementation, you can perform the same display, query, and analysis operations on both types of geodatabases. Note that there are some differences in functionality due to physical storage issues. Read the online documentation for more information. The geodatabase is a native data format for all ArcGIS applications. It stores point, line, and area data in an RDBMS table (e.g., Access, Oracle, DB2 and SQL Server). The ArcEditor and ArcInfo levels of ArcGIS allow you to create, edit, and delete ArcSDE and personal geodatabase feature classes. The ArcView level allows you to create, edit, and delete personal geodatabase features and use ArcSDE geodatabase features for various processes, such as queries, joins, and relates. Introduction 1-53

54 Advantages of the geodatabase A relational database management system (RDBMS) for spatial and attribute data Manage raster and vector data Custom features Multiuser editing Geodatabase Single storage location Relationships Scalable storage solutions Spatial and Attribute validation 1-54 Advantages of the geodatabase The geodatabase provides: Centralized spatial and attribute storage Easy to use standard behavior rules Multiple customization options Multiuser editing (ArcSDE geodatabase only) The geodatabase supports a variety of modeling, management, and analysis functions. One of its key benefits is that its implementation of tables, feature classes, feature datasets, and rules allows you to model reality more closely than was possible with other data models. The geodatabase data model can minimize the differences between logical and physical models of reality by incorporating more intuitive data objects. For example, a coverage or shapefile provides a mechanism to store a generic point feature that may require ARC Macro Language (AML) or Avenue programs to maintain its attribute validation rules and other behavior. The geodatabase lets you store an electrical transformer feature instead of just a generic point feature and then apply subtypes, attribute domains, and relationship rules and/or topological rules. Because your datasets are smarter, it is easier to create and maintain your data. The ability to model simple and complex relationships through the graphical user interface (GUI) means that no external programming is needed for most customization. An added bonus for ArcSDE geodatabases is the ability to support multiuser editing through versioned geodatabases. Introduction 1-54

55 Geodatabase validation Automate spatial feature and attribute behavior Speeds up data entry Enforces quality control Spatial Spatial validation Topology Geometric network Attribute validation Subtypes Domains Relationship classes 1-55 Validation means that geographic features can be made to allow certain types of editing, display, or analysis behavior, depending on circumstances that the user defines. Feature behavior is most easily implemented in the geodatabase. In the geodatabase, you can set two types of validations: spatial and attribute. Spatial validation Spatial validation can be used in two ways: topology or geometric networks. Both of these spatial validation types require a feature dataset, where dedicated feature classes participate in either the topology rules or the geometric network rules. A single feature class cannot participate in both. Both of these spatial validations are available in ArcEditor and ArcInfo. Attribute validation Attribute validation are of three types: subtypes, domains, and relationship classes. These types of validations are necessarily used with tabular data. Both of these validations are required for maintaining data integrity and efficiency during management, display, and editing operations on the geodatabase. ArcView and above can create and edit domains; subtypes can only be created with ArcEditor and ArcInfo. More information regarding any of these topics can be found in a variety of sources: ArcGIS Desktop Help Online at Instructor-led courses (e.g., I, Building Geodatabases I and II) Virtual Campus courses (e.g., Basics of the Geodatabase Data Model; Creating, Editing, and Managing Geodatabases for ArcGIS 8.3) Introduction 1-55

56 ESRI shapefile data format Shapefile Single feature class Attributes stored in dbase table Made up of separate files Can create and edit with ArcGIS or ArcView 3.x Use only ArcCatalog to manage shapefiles 1-56 Data format: Shapefile Shapefiles can only contain one feature class. Therefore, a donut shop point feature class (representing the building s point location) must be stored in a different shapefile as a donut shop polygon feature class (representing the building s footprint). Regardless of feature type, a shapefile s default attribute table is stored in dbase format and is named shapefile.dbf (e.g., donut.dbf). You can access this table in ArcGIS applications or dbase. Additionally, shapefiles are the native format for ArcView 3.x, so you can view, display, and edit both the spatial and attribute data in ArcView 3.x. Shapefiles are a vector file structure for storing the location and attribute information of points, lines, or areas. Each shapefile consists of at least three files: <name>.shp, <name>.shx, and <name>.dbf (e.g., donut.shp, donut.shx, and donut.dbf). However, there may be other files associated with the shapefile, which you might not recognize and therefore miss if you tried to copy or move the shapefile using your computer operating system. This is why you should only use ArcCatalog to copy, move, or rename shapefiles. Introduction 1-56

57 ESRI coverage data format Coverage Multiple feature classes Attributes stored in INFO table Can only be stored in an ArcGIS Workspace Edited only with ArcInfo Workstation Use only ArcCatalog to manage coverages 1-57 Data format: Coverage A coverage is the ArcInfo Workstation native vector format. It is stored as a folder containing both the locational data files and the descriptive data files for features in a given geographic area. It is a collection mechanism that may contain one or more feature classes. For example, a landuse coverage may contain both an area feature class representing contiguous landuse boundaries and a line feature class used to model the exact transitional location between landuse types. Area and line feature classes have separate attribute tables, but it is important to note that they share the same geometry. You can have points and lines (with attributes) in the same coverage, but they do not share the same geometry. The only limitation is that you cannot have both point and polygon attributes within the same coverage. ArcInfo coverage organization An ArcInfo workspace is simply an operating system folder with a subfolder named info. The info folder stores and manages the info format attribute tables for the coverages in the workspace. In addition to coverages, workspaces may also store any other type of geographic data (e.g., shapefiles, geodatabases, GRIDs), as well as related files, such as documentation or graphics files. It is very important to use only ArcGIS tools to manage and manipulate coverages and workspaces. ArcGIS tools are designed to preserve the link between the files stored in the coverage directory and the files stored in the info directory. Operating system file management tools are unaware of this link. Coverage files are stored in two folders: the coverage folder and the INFO folder. Files in both folders are required to reconstruct a coverage s spatial and attribute information. Introduction 1-57

58 CAD file data format Computer Aided Design files (DXF, DWG, DGN) Logical collection Display one or all feature classes Edit after converting to geodatabase FC or shapefile CAD file (read-only attribute tables) Shape Shapefield accesses read-only coordinates 1-58 Data format: CAD files Accessing CAD sources may be done individually by choosing the feature class to display and/or query, or you can view the entire CAD file feature class collection all at once. If you view all feature classes at once, you cannot change the symbology, and you cannot view the associated attribute table. CAD attribute tables Your geographic database may include GIS data stored in CAD format. ArcGIS supports DXF, DWG, and DGN formats. You can display and query the data as it exists in its native CAD file format, or you can convert it to a geodatabase feature class or shapefile if you want to edit the spatial features or attribute records. Each individual feature class within the CAD file has an associated attribute table, usually a.dxf file. This table displays the original attributes from the CAD file. The ability to display and query native CAD files is incredibly useful. For example, suppose you work for an organization where one or more departments create spatial data with CAD systems. Rather than re-creating the data to put in your GIS database, you can leverage the existing data. Converting CAD files The ArcToolbox Conversion Tools support both the import and export of DWG, DXF and DGN files to geodatabase and shapefile formats. The export to CAD functionality is new with ArcGIS 9. ArcMap supports the export of CAD data to shapefile or geodatabase feature class formats through the layer Data > Export Data function. ArcCatalog supports the export of CAD feature classes into coverage, shapefile, or geodatabase feature class formats. This is accessed through the layer context menu in the catalog tree. Introduction 1-58

59 Tabular locations to a point feature class Table Table with with raw raw coordinates New New feature feature class class Table Table with with addresses New New feature feature class class 1-59 Tabular locations You can add tabular data that contains geographic locations in the form of x,y coordinates to your map. x,y coordinates describe discrete locations on the earth s surface, such as the location of fire hydrants in a city or the points where soil samples were collected. You can easily collect x,y coordinate data using a global positioning system (GPS) device. In order to add a table of x,y coordinates to your map, the table must contain two fields, one for the x coordinate and one for the y coordinate (these fields might also be named northing and easting, or latitude and longitude ). The values in the fields may represent any coordinate system and units, such as latitude and longitude or meters. Once you have added the data to your map, the layer behaves just like any other feature layer. You may also create point features from a table of address locations through the process of geocoding or address matching to reference address data. Geocoding is covered in more detail in the I course. Introduction 1-59

60 Managing raster data Rows and columns of equal-sized cells Each cell stores a value Detail depends on cell size GRID (the ESRI native raster format) Images (TIFF, BMP, SID, JPEG, ERDAS) 1-60 Data format: Images and Grids Raster data files use rows and columns of equally spaced cells to model reality. There is a trade-off between file size and how closely you want to model reality. If you assume a given spatial extent, a small cell size (e.g., 6-inch pixel) captures more detail, but the raster file size is larger than a large raster cell size (e.g., 50-meter pixel), which captures less detail. It is not uncommon for a single high-resolution (i.e., small cell) image to be many gigabytes in size. Raster collection mechanisms A raster data source can be composed of a single layer or a collection of multiple layers, which appear to act as one (composite). ArcGIS supports many raster image formats, and these may be monochrome (black and white) or multispectral (many bands, or layers, representing many colors). ArcCatalog allows you to manage individual raster data sources in two ways: a Raster Dataset represents a single source of raster information; a Raster Catalog represents a number of individual raster data sources, which are displayed and managed as one. ArcGIS also uses an ESRI raster format called GRID. GRIDs may use a collection mechanism called a grid stack, which is used for certain types of analysis. There are several different types of GRIDs, so you should read the online documentation for more information about their formats and capabilities. Raster management in ArcGIS If you only want to manage the storage or display of rasters in ArcGIS, you can use ArcCatalog. However, if you need to use ArcGIS to create, edit, manipulate, or analyze raster datasets, you will need the Spatial Analyst extension. Introduction 1-60

61 Using Geography Network data Map or Data services Data clearinghouses Geoservices and solutions 1-61 Using Geography Network data The Geography Network is based on the collaboration of public and private organizations that publish and share GIS information on the Internet. It provides access to a wide variety of geographic content including static map images, dynamic map services, downloadable data, and data clearinghouses. The Geography Network is an evolving Internet platform, based on ArcIMS software technology, for both users and publishers of spatial data. There are two types of map services: Image Services and Feature Services. When you use an Image Service, the map image is generated for you by the map server in JPEG, GIF, or PNG format and does not require any special processing on your computer. With a Feature Service, the map server bundles the data and ships it to you through a process called streaming. This requires that you have the necessary Java applet or application, like ArcExplorer or ArcGIS, to interpret the data stream. With Feature Services, you are actually working directly with the data over the Internet. A data service lets you download geographic data files, or it can be a collection of links to data clearinghouses. When you download geographic files, you are getting a static copy of the data from the data provider s computer not a live map as in the Image or Feature Map Services described previously. Data clearinghouses are usually Web sites maintained by organizations and companies that handle specific types of information. The data may be categorized by geographic region, department, project, content, or by the digital characteristics of the data itself. Geoservices are Internet services that perform basic geoprocessing tasks such as geocoding, buffering, or routing. As a solutions developer, you would use geoservices to perform real time geoprocessing on the computer where the geoservices are located and pass back the results to your custom application, all over the Internet. In other words, you would not have to maintain the basic geoprocessing application tools or the associated geographic data on your computers in order to use them with your custom map service. Introduction 1-61

62 Using ArcCatalog Provides a uniform view of all your data Define or modify table and feature class definitions Manage data: Copy, Rename, Delete Additional data management tools with the ArcToolbox window 1-62 Using ArcCatalog ArcCatalog is the application where you create and manage connections to all the data you need to use. When you create a connection, you access the data to which it is linked, whether it is located on a local disk or a database on the network. Together, your connections create a catalog of geographic data sources. Within ArcCatalog, you can move, copy, rename, and delete geographic data. You can create, manage, and edit associated metadata, and you can perform some modifications to the data, such as adding fields to tables, defining subtypes, creating domains, and building table relationships. By adding the ArcToolbox window, you can also access all of the data management tools contained within the various toolboxes. Introduction 1-62

63 Three ways to view data Contents Preview Metadata 1-63 Three ways to view data In ArcCatalog, you can browse your data holdings three ways using three tabs: Contents tab The Contents tab shows what a selected item (e.g., folder, geodatabase, or feature dataset) in the catalog tree contains. There are four ways to view the contents of the item: as large icons, in list form, showing details (like data type), and in thumbnail view. Preview tab The Preview tab previews the selected item s geographic or tabular data. Geography view is the default preview mode. For items containing both geographic data and tabular attributes, you can toggle between the two preview types using the dropdown list at the bottom left corner of the Preview view. The available previews are not limited to Geography and Table. Developers can create their own custom previews and add them to the list. For example, an AML view might let you preview the contents of an AML file that has been added to the database. Metadata tab The Metadata tab shows a selected item s metadata. By default, when you first try to view an item s metadata, ArcCatalog automatically generates it if it does not already exist. Upon creation, ArcCatalog adds several of the data source s properties to the metadata. The next time you view or edit the metadata, ArcCatalog will automatically update these properties with the current information. Introduction 1-63

64 The Contents tab Large icons List Details Thumbnails Data Layers Maps 1-64 The Contents tab The Contents tab lists the items contained in any item you select in the catalog tree, such as folders, geodatabases, or feature datasets. In the Contents tab, you can look at the data listed in four different ways: Large icons: All items are represented by a large icon graphic in the main display window. List: The items are shown in a simple list with small icons to the left of the file names. Details: The items are shown in a simple list with small icons to the left of the file names (similar to the list view option), but additional information is also given, such as each file s data type. Thumbnails: All items are represented by thumbnail images in the main display window. The thumbnails are snapshots of the data at the time the thumbnail was created. Therefore, the thumbnail images can quickly become outdated and should be updated frequently. By default, thumbnails are automatically generated for map documents. For other items, a thumbnail must be created manually. If a thumbnail has not been created for an item, an icon describing the data type and name of the item appears in place of the thumbnail. Introduction 1-64

65 Creating thumbnail images Used by Contents thumbnail view Click the Preview tab Zoom and Pan (optional) Click Create Thumbnail icon Choose an object 1-65 Creating thumbnail images To create a thumbnail image in ArcCatalog, you must have the Geography toolbar displayed on the ArcCatalog interface. To access the toolbar, click View > Toolbars > Geography. To create a thumbnail, simply select the layer in the Catalog tree, click the Preview tab, and then click the Create Thumbnail tool in the Geography toolbar. In order to view the created thumbnail, click on the folder/geodatabase/feature dataset that contains the layer, click the Contents tab, and click the Show Contents As Thumbnail Images button on the standard ArcCatalog toolbar. You now see the thumbnail you created. Introduction 1-65

66 The Preview tab Geography or Table view Choose from dropdown list Build custom views 1-66 The Preview tab When an item is selected in the Catalog tree, the Preview tab previews the selected item s geographic or tabular data. At the bottom of the tab, there is a dropdown list that allows users to select which view they would like to see (either geography or table). Geography is the default view, where the data is displayed with a random color and/or symbol set. The table view option displays the attribute data associated with the selected feature class in tabular form. A third preview option, 3D view, is also possible if the 3D Analyst Extension has been added. You can build your own custom views if these three options do not meet the needs of your organization. Introduction 1-66

67 Introducing metadata Descriptive information about data source Metadata tab Description Spatial Attributes Metadata toolbar Create and edit content Convert between different file formats 1-67 Introducing metadata Often the definition given for metadata is data about data. While this definition is not incorrect, it is not very informative. More precisely, metadata supports descriptive information about data. Text written on the back of a photograph telling you the photograph s date and subject and nutrition labels on food containers are common examples of everyday metadata. For spatial data, metadata includes descriptive information such as date, creator, geographic extent, coordinate system, and attribute domains. Metadata gives your data credibility, and in many situations, your data may be impossible to interpret or use without it. The Metadata tab in ArcCatalog displays the metadata for a selected dataset. If metadata does not exist for the selected dataset, ArcCatalog creates as much metadata as it can from the existing information. For the FGDC ESRI stylesheet, the Metadata tab is divided into three categories, each with an active tab: Description contains the basic narrative information about the dataset, including source, organization, date, uses, and restrictions. Spatial contains the coordinate information and geographic extent of the dataset. Attributes includes fields, attribute domains, and related tabular information. You can create, edit, import, and export the metadata for any given dataset. Because metadata information is stored in XML format, you can use it with other software that can read XML documents. Introduction 1-67

68 The Metadata tab Create and display metadata in a variety of ways FGDC Classic FGDC_ESRI XML ISO 1-68 Viewing metadata You can view metadata in ArcCatalog by selecting an item in the catalog tree and then clicking the Metadata tab in the display area. There are a number of stylesheets available in ArcCatalog to view metadata. Stylesheets format data from a database and present the results as a report. Metadata is stored as an Extensible Markup Language (XML) file, and the stylesheets define how XML data is presented. Stylesheets are written using Extended Stylesheet Language (XSL). The stylesheets in ArcCatalog represent common standards for metadata. However, you can create your own customized stylesheet for displaying metadata in ArcCatalog using XSL. The Federal Geographic Data Committee (FGDC) is an organization established by the United States Federal Office of Management and Budget responsible for the coordination of development, use, sharing, and dissemination of surveying, mapping, and related spatial data. It is composed of representatives from several federal agencies and GIS vendors. The FGDC defines spatial metadata standards in its Content Standards for Spatial Metadata, and it coordinates the development of the National Spatial Data Infrastructure (NSDI). The International Organization for Standardization (ISO) is another common standard for collecting metadata on spatial data. Introduction 1-68

69 Connecting to folders Connect to any folder in your network Connect through Network Neighborhood to store a Uniform Naming Convention (UNC) path Example \\servername\foldername\filename.ext Use UNC in layer files or map documents Disconnect from folders 1-69 Connecting to folders Unlike Windows Explorer, ArcCatalog does not list all files stored on disk; so when you look in a folder, it might appear to be empty. By default, ArcCatalog only lists geographic data files. By default, ArcCatalog can access several types of geographic data (e.g., shapefiles, coverages). To enable ArcCatalog to access a new type of data, both spatial and nonspatial types, you need to specify the data type in the File Types list in the Options dialog. When you first start ArcCatalog, it contains folder connections that let you access your local computer s hard disks along with other folders called top level directories (e.g., Coordinate Systems, Address Locators). You can add additional folder connections that access specific folders or directories on a local disk, shared folders on the network, or the contents of a floppy or CD-ROM drive when needed. You can also connect through Network Neighborhood to store a Uniform Naming Convention (UNC) path. You can use UNC for layer files or map documents to reference a layer s source data. Lastly, you can remove folder connections and hide other folders that you do not need. Introduction 1-69

70 Adding tables from other databases Access diverse data sources OLE DB connection Connecting to Microsoft Excel? Refer to ESRI Knowledge Base for step-by-step instructions 1-70 Accessing existing databases You may access existing Info, dbase, or comma delimited text files simply by connecting to the folder that holds them. To access tabular data in other formats, you can use Object Linking and Embedding Database (OLE DB) providers. ArcCatalog communicates through an OLE DB provider, which then communicates with a different database. This standard lets you work with data from any database in the catalog in the same way. Looking in an OLE DB connection in the catalog, you will see a list of tables in the database. Microsoft s OLE DB providers come with ArcCatalog. They let you access Jet (Microsoft Access), SQL Server, and Oracle databases. Another provider communicates with Open Database Communication (ODBC) drivers. Connecting to an Excel spreadsheet in ArcCatalog A common request is to view data in a Microsoft Excel spreadsheet in ArcGIS. Though Excel is a spreadsheet application and not a database, information in Excel can be accessed through a connection by using the Microsoft OLE DB Provider for OBDC Drivers. The data in Excel can then be viewed as a table in ArcCatalog or added to ArcMap. Step-by-step instructions for connecting to an Excel spreadsheet can be found in the ESRI Knowledge Base. Go to and search for either Excel or for Article ID Introduction 1-70

71 Accessing data on the Internet Connect to an Internet Map Server Example: Geography Network 1-71 Connecting to an Internet server To access services provided by an ArcIMS Internet Server, add an Internet server connection to the catalog. To establish the connection, provide the Universal Resource Locator (URL), which uniquely identifies the server on the Internet. Your connection can access all the services provided, or you can choose to have it access only the specific services in which you are interested. Introduction 1-71

72 ArcCatalog Options Turn default data types on or off Add new file types Define Contents columns Choose Metadata default style Define Table appearance Raster display defaults Geoprocessor environment settings Check files for CAD DGN format compliance 1-72 ArcCatalog Options Tabs The Options tabs allow you to redefine ArcCatalog s default parameters for various functions. General select which top level entries (i.e., entries in the catalog tree such as Search Results or GIS servers) are displayed by default and which types of data you want the catalog to show. File Types add new file types, which are not contained within the list supplied in the General tab. Contents define which standard and/or metadata columns are displayed with data rows within the Contents view. Metadata define the default metadata stylesheet, Metadata Editor, and toggle on/off whether ArcCatalog automatically creates and/or updates metadata files. Geoprocessing set default global environment settings such as preferred location for storing new feature classes Tables choose how tables appear by default. Raster select which raster formats ArcCatalog recognizes, define how various raster formats are displayed, and ArcCatalog builds pyramids to facilitate faster raster display. CAD you can choose whether ArcCatalog does or does not check all file extensions for DGN compliance. It is recommended that users leave this off, in order to speed up ArcCatalog initialization and searches. Introduction 1-72

73 Add new file types New file types displayed in catalog tree Add nonspatial data formats Import file types from Windows registry Add new types not in registry 1-73 Add new file types When you click the File Types tab, you can add any data type to be recognized and visible in your catalog tree. There are two methods available to add a new file type: manually, where you define the file extension and description, and Import File Type From Registry, which gives you the option of choosing a file type from all of the types already registered with your operating system. This second method automatically populates the extension, description, and the icon, if available. When you double-click a file type in ArcCatalog that you have imported from the registry, the operating system launches the appropriate application registered to that file. One significant benefit of adding new file types is that ArcCatalog if you have set this function as active automatically creates metadata files for any file types it recognizes. Introduction 1-73

74 Working with tables Introduction 1-74

75 Lesson 5 overview Table structure Data types Table manipulation Connecting tables Working with graphs and reports 1-75 Introduction 1-75

76 Tables Descriptive information about features Each feature class has an associated table One row for each geographic feature Right-click 1-76 Tables A table contains formatted descriptive information. In ArcGIS, the information in a table is generally associated with spatial data, such as a feature attribute table but can also be independent of any spatial data (e.g., nonspatial statistical data). For the purposes of this course, you will consider only tables that contain information related to spatial datasets. The feature attribute table contains descriptive information about the features in a feature class. To open a feature attribute table in ArcMap, right-click the layer and then click Open Attribute Table. In ArcCatalog, you select the table and view it using the Preview tab. The feature attribute table consists of fields (also known as columns or items). Each field represents one type of descriptive information. Each row (also known as a record) contains the attributes of one feature in the dataset. Introduction 1-76

77 Understanding table anatomy Basic table properties Records/rows and fields/columns Column types can store numbers, text, dates Unique column names Columns (fields) Rows (records) Attribute values 1-77 Understanding table anatomy Each table has the same basic format: an array of rows and columns. With a table of spatial data, each row corresponds to a single feature. The intersection of a row and a column represents a specific attribute for a single feature. Different table formats have different numbers of preset default columns, but ANY table which stores spatial data must have at least two columns: a column, which stores a unique row identifier (e.g., ROWID, ObjectID), and a column, which stores the feature geometry (SHAPE). Introduction 1-77

78 Tabular data field types Different field types store different kinds of values Choose the right field type for the right value Field types vary according to table format Name: Jupiter Moons: 16 Diameter: 142,984 km Date of Comet Shoemaker-Levy impact: 7/16/1994 Rotation period: 9.8 hr Text Date Short Long BLOB Float Jupiter 7/16/ A 1-78 Tabular data field types Tables are capable of storing date, number, and text values, but most tabular formats have several different field types to store this information. Choosing the best field type for the values to be stored is an important consideration. In addition, the available field types can vary between tabular formats (e.g., Is the date field stored as dd/mm/yy, mm/dd/yyyy, or dd/mm/yyyy/hh:mm:ss?). Supported formats in ArcCatalog include short integer, long integer, float, double, text, date, and blob. Consult the online documentation for more information about these column types. Introduction 1-78

79 Table manipulation Open table in ArcMap or preview in ArcCatalog Sort ascending or descending Freeze/Unfreeze columns Statistics In ArcMap Select records Modify table values 1-79 Table manipulation ArcGIS can perform many table operations, such as sort, find, select, and freeze. In ArcCatalog, you can create new tables as well as create and delete fields for existing tables. In ArcMap, you can add fields (outside of an edit session) and add new or edit existing table record values. Introduction 1-79

80 ArcGIS tabular formats Each ArcGIS spatial format has a native tabular format Coverage: INFO Shapefile:.dbf Geodatabase: RDBMS tables ArcGIS can convert between formats Create a link between related tables in ArcMap Use ArcCatalog to connect to external tables 1-80 ArcGIS tabular formats ArcGIS supports the use of multiple formats for the storage and management of tabular information. Each of ArcInfo s primary spatial formats has its own native format. Coverages use INFO formatted tables; shapefiles store their attributes in dbase (.dbf) format; geodatabases rely on the format of their supporting RDBMS (e.g., Access or Oracle). Deciding on the proper format to store attribute information is an important part of database design and can affect how efficiently you access tabular information. To facilitate sharing of data in different formats, ArcGIS contains tools to convert between the various tabular formats. In addition, you can use ArcCatalog to connect to external tabular data sources by using the OLE DB connection option. Introduction 1-80

81 Associating tables Can store attributes in feature table or separate table Associate tables with common column key values Must be same data field types Must know table relationships (cardinality) Feature attribute table Additional attribute table 1-81 Associating tables Two tables can be connected, or associated, if there is a similar field in each table containing common values. In the example, the tables are linked by the common field called ZONE_CODE. Once the tables are connected, the description of what each zone code means (from the DESCRIPTION field) can be accessed from the feature attribute table by looking up the value in the associated table. Often features have many attributes, so most database design guidelines promote organizing your database into multiple tables each focused on a specific topic instead of one large table containing all the necessary fields. This scheme prevents duplicate information in the database because you store the information only once in one table. Tables can be connected so that when you need information that is not in the current table, you can access it from an associated table. Introduction 1-81

82 Table relationships How many A objects are related to B objects? Types of cardinality One-to-one, one-to-many or many-to-one, and many-to-many Must know cardinality before connecting tables One One parcel parcel has has one one owner owner One One parcel parcel has has many many owners owners Many Many parcels parcels have have one one owner owner Many Many parcels parcels have have many many owners owners or 1-82 Table relationships When you associate two tables together, you need to know how the individual record values relate to each other. The record relationships (cardinality) are: one-to-one, one-to-many (manyto-one), and many-to-many. Knowing which relationship type you have prevents potential record omission errors. For instance, if you have a one-to-many association and you connect the tables as if they were a one-to-one association, you omit needed information from the connected table because one-toone record searches stop looking for more matches after they find the first match. You can avoid these types of problems by becoming familiar with tabular database management strategies strategies that also make you a better GIS user. Read the sections about tabular management in the online documentation. Introduction 1-82

83 Joins and relates Two methods to associate tables in ArcMap based on a common field Join appends the attributes from one onto the other Label or symbolize features using joined attributes Relate defines a relationship between two tables 1-83 Joins and relates ArcMap provides two methods to associate data stored in tables with geographic features: joins and relates. When you join two tables, you append the attributes from one onto the other, based on a field common to both tables. When you relate tables, you define a relationship between the two tables also based on a common field but do not append the attributes of one to the other. Instead, you can access the related data when necessary. You join two tables when the data in the tables has a one-to-one or a many-to-one relationship (e.g., you have a layer showing store locations, and you want to join a table of the latest monthly sales figures to it). You relate two tables when the data in the tables has a one-to-many or many-to-many relationship (e.g., your map displays a parcel database, and you have a table of owners; a parcel may have more than one owner, and an owner may own more than one parcel). Joins and relates are reconnected whenever you open the map. This way, if the underlying data in your tables changes, it is reflected in the join or relate. Introduction 1-83

84 Connecting tables with joins Physical connection between two tables Appends the attributes of two tables Assumes one-to-one or many-to-one cardinality Parcel (before Join) ZoneCodeDesc Parcel (virtual table after Join) Many-to-one Parcel 1-84 Connecting tables with joins You can connect two tables in ArcMap using a join. Joins work with shapefiles, coverages, and geodatabase files. Once the tables are connected, you can query, symbolize, or analyze the new table based on the joined values. Tables connected by an ArcMap join are not permanently connected. The tables are dynamically linked together in ArcMap, and you can remove or add them whenever you want. When two tables are joined, the names of the common fields do not need to be identical, but the fields must be the same type (e.g., text, date, float). Table joins are designed for one-to-one or many-to-one relationships. For other cardinalities, you should use a relate instead of a join. If you use join with one-to-many or many-to-many cardinality, you omit all records after the first match for each primary key value. Introduction 1-84

85 Connecting tables with relates Define relationship between two tables Tables remain independent Additional cardinality choices One-to-many, many-to-many Discovers any related rows 1) Make selection 2) Open related table 1-85 Connecting tables with relates Another way to connect tables in ArcMap is by creating a relate. Like joining tables, relating tables defines a relationship between two tables and is also based upon a common field. Unlike joining tables, a relate does not append the fields of one table to the other. Instead, the two tables remain as independent tables in ArcMap. ArcMap knows the two tables are connected, and you can access data in the related tables when you need it. You relate tables instead of joining them when there is a one-to-many or many-to-many relationship between the tables or when you need to maintain the information in the related table independent of the feature attribute table. Introduction 1-85

86 Graphs Summarize tabular information A variety of graph formats Set display properties Add to a map 1-86 Graphs By displaying data values graphically, graphs simplify the often difficult task of interpreting the large amount of quantitative (numerical) attribute data associated with layers. You can represent your data and analysis results using many styles of graphs including twodimensional and 3D graphs. ArcGIS uses graphics server software that provides a variety of chart types so you can represent your data in the clearest and most efficient manner. Values for ArcGIS graphs come directly from feature attribute tables. Some graphs are better than others at presenting certain kinds of information. Carefully consider the information you want to present before choosing a graph style. You can control most visual aspects of the graph in order to create an effective display of your data. For example, you can add titles, label axes, change the color of graph markers, or change the color and font of the chart s text. Once you have created a graph, you can add it to a map in ArcMap s Layout View. When placed on the layout, a graph becomes a graphic element that you can size and position as desired. Introduction 1-86

87 Graph creation Graph Wizard is a high-end professional graphing and plotting utility 1-87 Graph creation The graphing tool in ArcMap can be activated in the Tools menu using the Graphs option. You can then create, manage, or load a graph. A series of wizard panels guides you through the process of creating a graph. Graphs present information about map features and the relationship(s) between them in an attractive, easy-to-understand graphic. They may show trends and/or patterns that are not easily visible in the attribute tables of the map features. They can show additional information about the features on the map or show the same information in a different way. The information displayed on a graph comes directly from the attribute information stored with your geographic data. Once a graph is created, adding it to your map is easy. Introduction 1-87

88 Reports Organize and display tabular data Group and format data Save and export Two reporting tools Report Writer Crystal Reports 1-88 Reports Displaying your data in a report allows you to organize your data. You can sort records based on the values in one or more field. For example, given a list of countries, you can sort them by total population or alphabetically by their name. Then you can easily see which country has the largest population. You can group records and calculate summary statistics (sum, average, count, standard deviation, minimum, and maximum values). Reports can be divided into a series of sections; each one identifies a particular area on the report. You control how a report looks by manipulating the contents of a section and by setting properties, such as size and color. For example, the section at the top of the report typically contains the title and subtitle of the report; however, you do not have to include either of these report elements if you do not need them. You can save a report to a file on disk and use it with another map or in other software products. (When you save a simple report to a file, you are creating a static copy that is not linked to the actual data from which the report was created; therefore, you will not be able to modify the report.) You can export reports to different file types including Adobe s Portable Document Format (PDF), Rich Text Format (RTF), or plain text (TXT). If you repeatedly use a consistent report design, you can build report templates that you can use to display information from different sources in a consistent manner. ArcGIS provides two tools for creating professional-looking reports from your tabular data. The Report Writer is an easy-to-use application available directly from ArcMap. It allows you to quickly produce reports for one table at a time. ArcGIS also comes with Crystal Reports. Crystal Reports has more advanced reporting tools available. Introduction 1-88

89 ArcMap Report Writer Quick, easy, professional report creation Add Add an an image image Choose fields fields Add Add borders Title Title Display records Calculate summary statistics Date Date and and page page numbers 1-89 ArcMap Report Writer Using the built-in ArcMap reporting tool, you can create reports that are stored directly with your map. Once created, you can add the report to your map layout and print it out. Introduction 1-89

90 Crystal Reports A more powerful reporting tool Export to Crystal Reports format Wizard aids report creation 1-90 Crystal Reports The ESRI Crystal Reports Wizard is available with ArcGIS. Crystal Reports is an advanced reporting application that provides you with tools for creating sophisticated reports. You can use the ESRI Crystal Report Wizard to lead you through the process of creating dynamic, customized reports for your spatial data, or you can access Crystal Reports directly from your computer s Start menu. Note: Crystal Reports 9 Standard Edition is distributed with ArcGIS. In order to access the reporting tools, you must first have Crystal Reports installed on your machine. This is an installation option you need to select when you first load ArcGIS. Introduction 1-90

91 Editing data Introduction 1-91

92 Lesson 6 overview Editing spatial data Navigating the Editor toolbar Editing tools Simple editing functions Working with sketches Editing attribute data Using the Attribute dialog on selected features Editing attribute values Making schema changes to tables 1-92 Introduction 1-92

93 ArcGIS editable data formats Shapefiles Personal geodatabase feature classes ArcEditor, ArcInfo to edit Enterprise geodatabase 1-93 Editable data formats All license levels of ArcGIS (ArcView, ArcEditor, and ArcInfo) allow you to edit shapefiles and feature classes in a personal geodatabase. An ArcEditor or ArcInfo license, along with ArcSDE, also allows you to edit an Enterprise geodatabase. Whether you are using ArcView, ArcEditor, or ArcInfo, you use the same editing tools in ArcMap to work on your geographic data. Data that is in the coverage format can only be edited using ArcInfo Workstation. Introduction 1-93

94 The Editor toolbar All editing functions are controlled through the toolbar Edit Edit Tool Tool Sketch Sketch Tool Tool Split Split Tool Tool Rotate Rotate Tool Tool Target Target layer layer Attribute Attribute dialog dialog Sketch Sketch Properties Properties Task Task list list Edit Edit session session commands commands 1-94 Navigating the Editor toolbar In ArcMap, editing operations are controlled through the Editor toolbar. The toolbar contains several important controls: Editor menu: This menu contains the commands for beginning, ending, and saving edit sessions. It also provides access to several editing operations, snapping controls, and editing options. Edit Tool: This tool is used to select features for editing. Sketch Tool: This is the primary tool for editing spatial features. It allows you to digitize in new features or modify the shape of existing features. The actual operation the tool performs is controlled by the Task list. Task list: You choose your desired editing operation from this dropdown list. Target layer: This control allows you to select the layer you want to edit. Split tool: Allows you to divide a select feature into two features. Rotate tool: Allows you to interactively rotate selected features using the mouse or an angular measurement. Attribute dialog: This window allows you to edit the attribute values of selected features. Sketch Properties: Allows you to edit the vertices of a sketch. Introduction 1-94

95 Managing edit sessions Starting a session Within one data frame at a time Within one geodatabase at a time Within one directory at a time Saving edits During the edit session At the end of the edit session Ending a session 1-95 Starting an edit session If you have started an edit session in a map document, where the layers come from more than one storage location (i.e., more than one personal geodatabase or network file directory), you are prompted to select the single data source, which will be edited. A personal geodatabase may only have one editor at a time; this does not mean one user but rather one application. For example, if you have started an edit session in ArcMap and move to ArcCatalog to delete or add fields to a table or feature class within the same personal geodatabase, you are not allowed to make your changes. This is because the first application to access the personal geodatabase puts a schema lock on the entire geodatabase. Managing edit sessions In ArcMap, you begin, end, and save edit sessions using the Editor menu on the Editor toolbar. When ending an edit session, ArcMap prompts you to save your edits. If you do not save, your edits are not committed back to the edit layer. Introduction 1-95

96 Selecting features Interactive or manual selection: pointing, box, line, area Selection menu: By Attribute, By Location Choice of selectable layers Selection anchor anchor 1-96 Selecting features ArcMap provides several methods for selecting the features you need to edit. These methods break down into three basic categories. Interactive (graphic) Selecting features by pointing or by drawing a shape (box, line, or area) Attribute Selecting by attribute values Location Selecting using features according to their spatial relationship to features in other layers (e.g., streets that intersect railroads) You can control which layers are available through the Selection menu. (You were introduced to Attribute and Location selection methods in Lesson 4.) Introduction 1-96

97 Simple editing functions Moving Click and drag Delta x,y coordinates Set sticky move tolerance Rotating Others Delete Copy Undo/Redo Cut Paste 1-97 Editing functions ArcMap contains several simple functions for editing spatial features. You can select features and move them by dragging or by using discrete coordinates. Features can also be rotated interactively around their selection anchor. The anchor can be moved anywhere on the page to achieve the desired result. In addition, you can use the generic Windows OS delete, cut, copy, and paste tools and their associated default shortcut keys (Ctrl+X, Ctrl+V, and so on). The Undo button steps back until your previous save. If you hover your cursor over the Undo or Redo button, a ToolTip appears, which tells you which operation is next. Sticky move tolerance The Sticky move tolerance is an option that can be set to prevent features from inadvertently being moved during an edit session. The default value for this option is 0. For example, if a value of 30 pixels is entered, the selected feature does not move at all until the mouse has been moved 30 pixels. The feature then jumps to the location of the mouse. This function works independently of the snapping environment with a number of editing tools but is set in the same Options dialog General tab as the snapping tolerance. Introduction 1-97

98 Working with sketches Use to create, modify, reshape features Sketch Sketch Tools Tools Temporary graphic represents feature geometry Left mouse button adds vertices or points Double-click or F2 key to finish sketch Right-click to access context menu 1-98 Working with sketches In ArcMap, every feature s geometry is represented by a sketch. A sketch consists of vertices (the end points of line segments, which normally indicate a change in direction) and segments (the lines that connect the vertices). When you edit a feature in ArcMap, you are working with its sketch, not the original features. ArcMap allows you to edit existing features or to create new ones in an existing feature class. To create a new feature, you must first create a sketch. Likewise, to edit a feature, you must edit its sketch. When you save, the feature is updated with the changes you made to its sketch. You can create only line and polygon sketches because points have neither vertices nor segments. The Sketch Tool is the primary editing device in ArcMap. It lets you add new features by digitizing or lets you modify existing features by performing an editing task from the Edit task list. When using the Sketch Tool, the left mouse button adds features, and the right mouse button accesses the Sketch Tool context menu. You can double-click to finish your sketch or by rightclicking to access the context menu and choosing to Finish Sketch. From the context menu, you also have the option to Finish Part. This allows you to create multipart features (e.g., many islands that belong to one country). Introduction 1-98

99 Using snapping Layer snapping Snap sketch to existing feature s edge, vertex, or endpoint Edit Sketch Snap sketch relative to the current sketch 1-99 Snapping Snapping automatically moves your pointer to the location or orientation (parallel or perpendicular) of a feature. This prevents you from having to click the exact coordinate of a feature in order to connect the feature you are editing. The snapping tolerance is the distance the pointer must be to a feature before it snaps to that location. You can set the snapping tolerance in map units or pixels through Options from the Editor menu. Using snapping There are two general varieties of snapping in ArcMap. Layer snapping: Moves your pointer to the location of a feature s edge, vertex, or endpoint. You can decide which, if any, of these options is available for snapping. Sketch snapping: When adding a sketch, this option snaps your pointer to a location perpendicular to the previous sketch segment. The snapping can be overridden if you move your pointer far enough. Setting the proper tolerance for snapping is sometimes a trial and error process. You should try the default tolerance first and then change it in small intervals until you settle on one that is appropriate to the data and your needs. Introduction 1-99

100 Edit tasks Sketch tool works with the current task Task examples: Current task task Create New Feature Modify Feature Reshape Feature Extend/Trim Features Cut Polygon Features Auto-Complete Polygon Edit tasks Many different edit tasks are available in ArcMap. These different tasks work in conjunction with the Sketch Tool. Some of these tasks may automatically be selected depending upon the geometry being edited and whether you are editing a new sketch or existing features. A sample of these edit tools is discussed in the next few pages. Introduction 1-100

101 Create New Feature task Sketch is used to add new features to the Target layer Sketch Sketch Tool Tool Target Target layer layer Finished Sketch Editor toolbar menu operations also create new features Create New Feature task You can create a sketch by creating the vertices and segments that make up the features. Vertices are marked in green, with the last vertex added marked in red. The Sketch Tool is the tool you use most often to create a sketch. It has an accompanying context menu that helps you place vertices and segments more accurately. Other operations You can create new features by using a basic Copy/Paste operation between target layers. Additional functionality and control can be found under the Editor toolbar dropdown list. Depending upon the geometry of your selected features and the target layer, you will have access to one of a number of editing operations, which create new features. These functions are: Move, Split, Divide, Buffer, Copy Parallel, Merge, Union, Intersect, and Clip. More information regarding these functions can be found in the ArcGIS Desktop Help or in the I course. Introduction 1-101

102 Modify Feature and Reshape Feature Modify Feature Task Edit the vertices of an existing feature Modify one feature at a time Shortcut: Double-click with the Edit Tool Reshape Feature Task Feature takes the shape of the intersecting sketch Modify Feature task The Modify Feature task allows you to edit the vertices of an existing feature to change its shape. While using the Modify Feature task, you may only modify one feature at a time. Hover your mouse pointer over the vertex you want to modify. You notice that the cursor icon changes. Click on the vertex and drag it to a new location. Reshape Feature task The Reshape Feature task can be used to digitize a sketch that becomes part of the feature you are reshaping. You start by sketching the new shape of the feature, ensuring that your sketch intersects with the existing feature. Introduction 1-102

103 Extend/Trim Features and Cut Polygon Extend/Trim Features Extend Extend to to sketch sketch Trim Trim to to right right of of sketch sketch Cut Polygon Features Cut Cut into into two two parts parts Extend/Trim Features task Often when creating new features, you may end up with features that are either too short or too long. There are tools in ArcMap to remedy these undershoots or overshoots. Extend feature to the sketch You can fix an undershoot with the Extend/Trim Features task. First you need to select the feature to be extended. Then sketch a short line to where you want to extend it (most likely another line). Once you sketch the second vertex, the selected feature extends to meet your sketch. Trim features on the right side of the sketch You can also fix an overshoot with the Extend/Trim Features task. First you need to select the feature to be trimmed. Then sketch a short line to where you want to trim it to (most likely another line). Once you digitize the second vertex, the selected feature trims to the right of where it meets your sketch. The sketch disappears from the screen. Cut Polygon Features task The Cut Polygon Features task can be used to sketch a line that splits one polygon into two. This tool is especially useful for parcel management. The sketched line must intersect both sides of the polygon feature to cut it. Introduction 1-103

104 Auto-Complete Polygon Automatically maintain coincidence Align new polygon with existing features Auto-Complete Polygon The Auto-Complete Polygon task allows you to add a new polygon to the edge of existing polygon features without having to sketch in a duplicate boundary between them. Using this task, you sketch in all the polygon boundaries except the one common to the other adjacent polygon(s). This task is extremely useful for maintaining data quality; by using this task, you eliminate the potential for creating small sliver polygons when digitizing. Introduction 1-104

105 Creating a vertex or point Intersection Adds a vertex at the implied intersection of two segments Distance-Distance Adds a vertex at given distances from two points Absolute X,Y Radius = 40 Radius = 55 New point Intersection tool The Intersection tool creates a point or vertex at the implied intersection of two segments based on existing features. Implied means that the segments do not have to actually intersect on the map. The Intersection tool creates a point or vertex at the place where the segments would intersect if extended far enough. Distance-Distance tool Suppose you want to install a pole at a certain location. If you do not have the exact coordinate location but know that it is at the intersection of 40 meters from the corner of one building and 55 meters from the corner of another, you can use the Distance-Distance tool to place the point. The Distance-Distance tool allows you to create a vertex or point at the intersection of two distances from two other points. Absolute X,Y You access this function through the Sketch Tool context menu. If your target layer is a point feature class, a new point can be created at an explicit location based on map units. If your target layer is a line or polygon feature class, the coordinates are used as an insertion point for a new vertex from which you start a new sketch. Introduction 1-105

106 Adding curves Sketch using a 3-point parametric curve End End Point Point Arc Arc Regular Arc Arc 2 End Start Create curve based on previously sketched segment 1 Start Tangent Tool Tool Arc tool Creates a sketch segment using a 3-point parametric curve. Click to place the start point, click again to place an invisible midpoint through which the curve passes, and click a third time to place the endpoint of the curve. End Point Arc tool When a parametric curve is created using the Arc tool, the radius for the curve is controlled by the placement of the last point. This differs from how curves are created using the Arc tool. The End Point Arc tool creates a circular arc with an adjustable radius. The first two points are specified for the start and end of the curve. The third point controls the radius. The radius can be set interactively by moving the mouse or by pressing the R key to enter an explicit radius value. Tangent tool The Tangent tool creates a circular arc based on the previously sketched segment. This tool does not become enabled unless there is at least one sketch segment present. The radius of the curve being created is dependent on the placement of the endpoint. Introduction 1-106

107 Trace tool Trace along selected features Select features Click to start and stop the trace Press O to specify an offset Trace tool You can create segments by tracing over the segments of selected features using the Trace tool. Suppose you want to create a new water main that is offset five meters from the parcel boundaries. Using the Trace tool, you can create new segments in the sketch that are at the same angle as the selected parcel boundaries but constructed at an offset value of five meters. Introduction 1-107

108 Sketch context menus Right-click is location sensitive Sketch Sketch context menu menu Sketch Sketch Tool Tool context menu menu Cursor directly over last vertex Cursor away from last vertex Context menus for editing A context menu is a floating menu that pops up at the location of the pointer when you press the right mouse button. There are two types of context menus related to sketches: a Sketch Tool context menu and a Sketch context menu. Sketch Tool When using the Sketch Tool, you access the Sketch Tool context menu by right-clicking the mouse away from the sketch you are creating. The menu contains options for placing the vertices and segments specifically where you want them. For example, you can set a segment to be a certain length or angle or create a vertex at a specific x,y coordinate location. Sketch The Sketch context menu works with both new sketches and sketch elements, as well as sketches derived from existing features. You expose the sketch for existing features by first selecting the feature(s) with the Edit Tool and double-clicking. You see that the original feature remains selected (highlighted with the default cyan color), but the sketch has now been added for you to edit. Introduction 1-108

109 Modifying existing features Double-click feature to expose sketch elements Insert Vertex Delete Vertex Move vertices delta x,y or exact x,y Editing vertices The Sketch context menu allows you to manipulate existing vertices; use the Edit Tool to select and double-click a feature to expose the sketch. You can insert a vertex by right-clicking on a sketch at the location where you want to insert a vertex. You can also delete and move vertices. You can move a vertex to a specific x,y location by clicking Move To, or you can click Move and specify a distance to move the vertex in the x and y direction. Note the difference between the selected feature and the sketch as illustrated in the slide (most obvious with the Delete Vertex example). Until you click Finish Sketch, you have only manipulated the sketch, not the underlying feature s geometry. Introduction 1-109

110 Control sketch elements Next sketch segment Direction/Length Direction = 30 Length = m Directions based on existing features Parallel Parallel to Lengths There are two ways you can specify length using the Sketch Tool context menu. Specify a length constraint from the last vertex You can choose Length from the context menu when your next vertex will be at a certain distance from the current vertex. This creates a line segment of a specific length. Change the length of the last segment The Change Length option allows you to change the length of the last segment created. Specifying direction Sometimes features are required to be entered with specific directions between their component segments. ArcMap is equipped with specific direction measurement tools for data entry. Rightclicking on a point slightly away from the last vertex entered brings up the Sketch Tool context menu with several choices of how to enter directional data. Angles based on other features Angles can also be measured based on the direction of other features. The Sketch Tool context menu shows three such options: Parallel, Perpendicular, and Segment Deflection. Hold the pointer on the segment you want to base your angle on, and right-click to select the option from the context menu. The Segment Deflection option can be used to create a segment at an angle from another segment. Here you are maintaining the angle of the new segment to be the same as the deflection angle of an existing segment. Parallel constrains a new segment to be parallel to an existing feature. Perpendicular constrains a new segment to be perpendicular to an existing feature. Introduction 1-110

111 Editing attribute data for selected features Attribute dialog allows viewing and editing of selected feature attributes Selected Selected feature feature layer layer name name Click Click to to highlight highlight selected selected feature feature Right-click Right-click opens opens context context menu menu Primary Primary attribute attribute Attribute Attribute values values Add or copy/cut and paste values for single or multiple selected features Editing attribute data The Attributes dialog lets you view attributes of features you have selected in your map. The left side of the dialog contains a list of the features you have selected. Features are listed by their primary display field and grouped by layer name. The right side of the Attributes dialog contains two columns: the attribute properties of the layer you are viewing, such as Type or Owner, and the values of those attribute properties. You can copy individual attributes or all the attributes of a feature. Attributes can be pasted to a single feature or to all selected features in a layer. To copy an attribute value to a layer, copy the value and right-click on the layer name. Click Paste, and the attribute value is copied to every selected feature in the layer. You can cut and paste attributes just like you copy and paste attributes by choosing Cut from the context menu. Cut removes the attribute value you are copying from the Attributes dialog. Introduction 1-111

112 Editing attributes on an open table Direct edits to a single cell Use the Field Calculator Calculate field values for an open table Simple calculations or advanced functions In or out of an ArcMap edit session Field Calculator By accessing the Field Calculator, you can edit attribute values directly on the attribute table. Open the calculator by right-clicking the field you want to edit values for. The Field Calculator menu lets you perform simple calculations and complex logical expressions that can include other fields in the table. You can use this functionality in ArcMap at any time, but if outside an edit session, you do not have the ability to undo your operation should an error occur. Introduction 1-112

113 Making schema changes Sometimes the database structure must be updated Add table fields Delete table fields Create new feature classes and feature datasets Create new personal geodatabases Even good database designs cannot predict everything ArcCatalog is the schema editor Schema Schema is the term used to describe the structure of data layers (tables, feature classes, and so on) and geodatabases. Schematic design may include more than just table column structures. Schema may also describe such objects as permanent, database-level relationships between tables, attribute validation structures, feature datasets, geometric networks, and more. ArcCatalog is the schema editor for ArcGIS and provides you with all of the tools necessary to create and maintain spatial and attribute data structures. Licenses and data types With ArcView, you are able to edit only geodatabase tables and shapefile dbase (.dbf) files. ArcEditor gives you additional editing functionality with Enterprise geodatabase tables (i.e., SDE Layers); ArcInfo provides you with additional tools to manipulate coverage table files. Introduction 1-113

114 Schema changes in ArcMap Add fields Must be outside edit session Export data Tables in ArcMap The relationship between ArcGIS applications is: ArcCatalog is the schema editor, and ArcMap is the feature and attribute editor. ArcMap provides you with many tools to edit, manipulate and create attribute values. However, you can perform some limited schema editing with ArcMap; specifically, you can add a new field to a table. In order to do this, you need to be outside of an edit session. This is due to the fact that once you start an ArcMap edit session, ArcGIS puts a schema lock on any feature classes that are being edited. Another method for making schema changes in ArcMap is to export data. ArcMap gives you the option of creating a new shapefile or geodatabase feature class from all or selected features. This necessarily creates new schema, as the existing feature attributes are transferred to the new feature class. Introduction 1-114

115 Adding table fields in ArcCatalog Type Type in in new new field field name name Choose the the field field type type Set Set the the field field properties Adding fields To add a new field to an existing table in ArcCatalog, first access the table Properties dialog and click the Fields tab. Click the first empty cell under the Field Name and type in the name of the new field. Under Data Type, click the down triangle to get a listing of possible data types to select from. Once selected, the Field Properties panel expands so you can set additional properties for the new field. Set an appropriate length for the field. Deleting fields In the same Feature Class Properties tab, select the field and push the delete key. Keep in mind that there is no undo function in ArcCatalog, and once deleted, you will not be able to retrieve any lost information. Introduction 1-115

116 Schema changes with ArcToolbox Copy rows Create table Create feature class Convert data ArcToolbox Tools ArcToolbox contains a number of tools, which involve schema edits. Some examples: Conversion Tools import existing table structures Data Management Tools allow you to create new tables, copy rows, drop fields, and more Layers and Table Views provide the option of creating new tables from a number of source tables, as well as virtual table views Introduction 1-116

117 Create New Feature Class Similar to table but with geometry data type Define Geometry Type Define Spatial Reference Create New Feature Class When creating a new empty feature class, you use ArcCatalog to define the schema. You are presented with a number of interface panels, which prompt you to define various parameters of the new feature class. The most important of these parameters, Geometry Type and Spatial Reference, are defined for the SHAPE field, which stores the geometry of the features. Introduction 1-117

118 Working with georeferenced data Introduction 1-118

119 Lesson 7 overview Georeferencing Coordinate systems Datums Projections and distortion Projecting your data Introduction 1-119

120 What is georeferencing? Data is referenced to a location on the earth s surface Geographic coordinate systems Projected coordinate systems What is georeferencing? People working with a GIS are interested in analyzing relationships among real-world objects. It is important to recognize that a GIS only depicts abstractions of reality. Therefore it is crucial to depict the real world as accurately as you can if you want accurate analysis results. When representing real-world features in a GIS, you need to reference the data describing them to the correct location on the earth s surface. This is called georeferencing. If features are not located precisely or if their shapes are represented incorrectly, using a map or GIS to analyze their spatial relationships yields inaccurate results. Georeferencing is the process of establishing a relationship between the data displayed in your GIS software and its real-world location. This is accomplished by using a coordinate system. To get accurate analysis results from your GIS database, you need to understand and determine your coordinate system. An ellipsoid, datum, a projection, and units make up a coordinate system. Introduction 1-120

121 Coordinate systems - X + Y -X -Y Y Data + X + Y usually here + X - Y X Geographic coordinate system Latitude and longitude are not uniform across the earth s surface Cartesian coordinate system Measures of length and angle are uniform Geographic The most common locational reference system is the spherical coordinate system measured in latitude and longitude. This system can be used to identify point locations anywhere on the earth s surface. Because of its ability to reference locations, the spherical coordinate system is usually referred to as the Geographic Coordinate System, also known as the Global Reference System. Longitude and latitude are angles measured from the earth s center to a point on the earth s surface. Longitude is measured east and west, while latitude is measured north and south. Longitude lines, also called meridians, stretch between the north and south poles. Latitude lines, also called parallels, encircle the globe with parallel rings. Latitude and longitude are traditionally measured in degrees, minutes, and seconds (DMS). Longitude values range from 0 at the Prime Meridian (the meridian that passes through Greenwich, England) to 180 when traveling east and from 0 to 180 when traveling west from the Prime Meridian. Planar Because it is difficult to make measurements in spherical coordinates, geographic data is projected into planar coordinate systems (often called Cartesian coordinates systems). On a flat surface, locations are identified by x,y coordinates on a grid, with the origin at the center of the grid. Each position has two values that reference it to that central location; one specifies its horizontal position and the other its vertical position. These two values are called the x coordinate and the y coordinate. Introduction 1-121

122 Datums and datum conversion A frame of reference for measuring locations on the surface of the earth Measurements are referenced to a geodetic origin and an ellipsoid model Meades Ranch Kansas Local Local datum datumnad27 Ellipsoid CLARKE Earth-centered datum datumnad83 Ellipsoid GRS80 GRS80 + Earth s surface Earth s center Datums and datum conversion A horizontal datum is a reference frame used to locate features on the earth s surface. It is defined by an ellipsoid and that ellipsoid s position relative to the earth. There are two types of datums: earth-centered and local. An earth-centered datum has its origin placed at the earth s currently known center of mass and is more accurate overall. A local datum is aligned so that it closely corresponds to the earth s surface for a particular area and can be more accurate for that particular area. Within both of the basic types of datums, you can have several global and local datums. Because datums establish reference points to measure surface locations, they also enable us to calculate planar coordinate values when applying a projection to a particular area. Ellipsoid The earth is often treated as a sphere to make mathematical calculations easier; however, its shape is actually an ellipsoid. Rotating an ellipse about an axis forms an ellipsoid. An ellipsoid is like a flattened circle with radius lengths along its major and minor axes of length a and b, respectively. The diagram shows that the ellipsoid is symmetric when divided at the equator (i.e., the southern hemisphere and the northern hemisphere are identical in shape). This is not strictly correct, because the earth is slightly pear-shaped; however, the difference in shape between the hemispheres is very slight. Introduction 1-122

123 Referencing locations Locations on the earth are referenced to the datum Different datums have different coordinate values for the same location UTM NAD83 I-10 through Redlands, CA UTM NAD Referencing locations Two maps using the same map projection but different datums can have very different coordinate values for the same location on the earth s surface. The above graphic shows data for Interstate 10 through Redlands, California, using two different datums. Although both datasets are in UTM projections, the datums used to reference those projections are different. In this case, the difference equals about 175 meters. Checking the datum, as well as the projected coordinate system of a dataset, is vital for matching different data sources in the same coordinate space. Introduction 1-123

124 Map projections Map projections convert curved surface to flat surface Cylinder Cone Plane Map projections A map projection is a method for converting the earth s 3D surface to a map s two-dimensional surface. A map projection can represent the earth s entire surface or only a portion of it, depending on your needs. The term map projection was coined by early cartographers, who employed the concept of projecting light from a source through the earth s surface and onto a two-dimensional surface. Although maps are created using mathematical formulas rather than projected light, the concept is valid, and cartographers use the term projection to describe the mathematical process. Today, all projections use formulas: mathematical expressions that convert data from a geographic location (latitude and longitude) on the earth to a representative location on a flat surface. Projection surfaces The selection of a suitable map projection is important if you are going to calculate areas, distances, or directions from coordinates. To help us understand map projections better, you can group them into classifications. One way to group them is by their distortion characteristics such as shape, area, distance, and direction. Another way is to classify them by the developable surface used to make the projection equations. There are three developable surfaces: cylinders, cones, and planes, each giving a distinctive shape to the parallels. With cylinders, parallels are straight; with cones, concentric circles are formed; with planes, eccentric circles are formed. Most common map projections may be conceptually or geometrically projected onto one of these surfaces touching or intersecting the globe. In most cases a projection has already been chosen by others for your area, and no selection is necessary. Introduction 1-124

125 Projection distortion Distortions make geographers SADD 3D Earth 2D Map Shape Area Distance Direction Projection distortion The conversion of geographic locations from a geographic coordinate system to a Cartesian coordinate system causes distortion. The projection process distorts one or more of the spatial properties listed below. Shape Area Distance Direction Because spatial properties are often used to make decisions, anyone who uses maps should know which projections distort which properties and to what extent. For example, choosing a Peters projection gives you accurate area calculations but inaccurate shapes; a Mercator projection maintains true direction but sacrifices accuracy for area and distance; and a Robinson projection is a compromise of all the properties. The projection you choose significantly affects the properties of a small-scale map but has less effect on the properties of a large-scale map. Introduction 1-125

126 Types of projections Generally classified by the spatial attribute they preserve Projection type type Maintains Example Conformal Equal Equal area area Equidistant Azimuthal Shape Shape Area Area Distance Direction Lambert Conformal Conic Conic Albers Albers Equal Equal Area Area Conic Conic Equidistant Conic Conic Lambert Equal Equal Area Area Azimuthal Types of projections Map projections can be generally classified according to what spatial attribute they preserve. Equal area Equal area projections preserve area. Many thematic maps use an equal area projection. Maps of the United States commonly use the Albers Equal Area Conic projection. Conformal Conformal projections preserve shape and are useful for navigational charts and weather maps. Shape is preserved for small areas, but the shape of a large area such as a continent is significantly distorted. The Lambert Conformal Conic and Mercator projections are common conformal projections. Equidistant Equidistant projections preserve distances, but no projection can preserve distances from all points to all other points. Instead, distance can be held true from one point (or from a few points) to all other points or along all meridians or parallels. If you will use your map to find features within a certain distance of other features, you should use an equidistant map projection. Azimuthal Azimuthal projections preserve direction from one point to all other points. This quality can be combined with equal area, conformal, and equidistant projections, as in the Lambert Equal Area Azimuthal and the Azimuthal Equidistant projections. Other projections minimize overall distortion but do not preserve any of the four spatial properties of area, shape, distance, and direction. For example, the Robinson projection is neither equal area nor conformal but is aesthetically pleasing and useful for general mapping. Introduction 1-126

127 Coordinate system components Projected data Geographic Coordinate System Datum Ellipsoid Projected Coordinate System Equations Parameters Coordinate system components Information about the coordinate systems for your data is sometimes referred to as the spatial reference. The spatial reference is composed of all of these components, the geographic coordinate system and the projected coordinate system. The ellipsoid that models the shape of the earth and the datum that references the ellipsoid make up the geographic coordinate system. Spatial data referenced with a geographic coordinate system can be projected into a planar or projected coordinate system so that measurement units are uniform throughout the data. The projected coordinate system is composed of the projection itself plus additional defining parameters. These parameters include the units, (e.g., meters or feet), the central meridian, possibly a zone depending on the projection, and sometimes a false easting or northing. False eastings or northings may be applied to the coordinate values so that spatial data is referenced by positive units. Information on all these components is stored with the projection information for the spatial data. Introduction 1-127

128 Storing projection information Many spatial data formats store the projection details along with the data Projected Projected Coordinate Coordinate System: System: Name: Name: PCS_Transverse_Mercator Alias: Alias: Abbreviation: Abbreviation: Remarks: Remarks: Projection: Projection: Transverse_Mercator Transverse_Mercator Parameters: Parameters: False_Easting: False_Easting: False_Northing: False_Northing: Central_Meridian: Central_Meridian: Scale_Factor: Scale_Factor: Latitude_Of_Origin: Latitude_Of_Origin: Linear Linear Unit: Unit: Meter Meter ( ) ( ) Geographic Geographic Coordinate Coordinate System: System: Name: Name: GCS_North_American_1983 PRJ file World file AUX file RDBMS table Shapefiles Coverages CAD files Images Geodatabase Storing projection information With many spatial data formats, it is possible to store the details of a dataset s projection as a part of the dataset. Most data formats accomplish this with a separate text file that is associated with the dataset. In shapefiles and coverages, this is called a projection file (PRJ extension). In CAD datasets, it is called a world file. Images store this information in an auxiliary file (AUX extension). The geodatabase is unique in that it can store the spatial reference information within the database. This alleviates the need for a separate file. Storing the projection and spatial reference information with a particular dataset is helpful because it provides users easy access to this key information and allows ArcMap to instantly recognize the projection of a data source. Introduction 1-128

129 Viewing projection information Examine metadata or feature class properties Use the Define Projection tool to assign projection Create new.prj file Viewing projection information Check your data s projection information under the Spatial tab in the metadata or open the feature class properties in ArcCatalog. Define Projection tool The Define Projection tool creates or modifies the parameters of standard and custom projections of a geodataset and stores the information in the feature class properties. Use this wizard if your shapefile, CAD data source, or image file does not have a defined projection and PRJ file. Introduction 1-129

130 ArcMap and projections Many supported projections Predefined projection files Support on-the-fly projection in ArcMap Mollweide North Pole Stereographic Fuller (World) ArcMap and projections ArcMap supports many standard projections and has hundreds of projection files predefined for specific zones and regions. A data frame s projection can either be explicitly set by the user, or ArcMap defaults to the projection of the first layer added. When subsequent layers are added to the map, they are automatically projected into the default map projection. When ArcMap performs an on-the-fly projection on a map layer, it is not changing the original projection of the data source. Therefore, it is usually not necessary to physically change a dataset s projection in order to perform display, query, or even analysis with datasets of a different projection. However, if a permanent projection change is needed, ArcToolbox contains the tools necessary to perform the operation. Introduction 1-130

131 Changing projections Change the way features (or coordinates) are projected Use Project tool in ArcToolbox Data Management tools Input projection must be defined Select from predefined coordinate systems Import the coordinate system from an existing dataset Create your own projection Changing projections Here are a few things to consider when choosing a projection: Which spatial properties do you want to preserve? Where is the area you are mapping? Is your data in a polar region? An equatorial region? What shape is the area you are mapping? Is it square? Is it wider in the east-west direction? How big is the area you are mapping? On large-scale maps, such as street maps, distortion may be negligible because your map covers only a small part of the earth s surface. On small-scale maps, where a small distance on the map represents a considerable distance on the earth, distortion may have a bigger impact, especially if you use your map to compare or measure shape, area, or distance. Answering these questions determines what map projection and, therefore, what projected coordinate system you will want to use to display your data. Introduction 1-131

132 Presenting data Introduction 1-132

133 Lesson 8 overview Basic cartographic concepts Creating maps in ArcMap Printing and plotting maps Introduction 1-133

134 Map and design objectives Map objectives Share information Highlight relationships Illustrate analysis results Decision support Design objectives Manipulate the graphic characteristics Fulfill the intended purpose Map and design objectives A map conveys geographic information, highlights important geographic relationships, and presents analysis results. Because most GIS users have to present their spatial data graphically to a wide variety of readers, they have also become map designers or cartographers. Any GIS analysis ends with some results that need to be communicated. You can help fulfill the purpose of your map by using proper placement of map elements and choosing symbols and cartographic elements that are tailored for the message you want to communicate. How you design a map depends on your particular objective (i.e., why you want to create a map in the first place). One obvious objective for creating a map is to show the results of your analysis. Other map objectives may be to simply share information, guide people, or highlight relationships. Your primary objective is usually not to create a beautiful map but to create a product that communicates effectively, efficiently, and clearly. Introduction 1-134

135 Factors controlling cartographic design Audience? Reality? Objective? Technical limits? Final design Final design Scale? Mode of of use? Need to to generalize? Several factors control your map design and can limit your creativity and flexibility. Map objective You may be asked to design a map for a book or for a wall, folded or flat, black and white or colored, square or rectangular, and so on. Each of these would control how you design the map. Audience Is your map for a highly technical committee or the general public? Your design must match the level of your audience. This controls the complexity of your map design. Reality and the need to generalize A detailed coastline is important for ecological studies. Your map must be detailed if you are addressing ecologists because they make deductions based on the way the coastline is shaped. A meandering river is important for city planners. You cannot generalize these complex shaped lines extensively (e.g., into a straight or large curved line) when going into a smaller-scale map. Scale and technical limits Scale dictates how much detail you are able to place on a limited piece of paper. At a scale of 1:1,000,000, a 10-meter road should appear on the map using a line width of 0.01 mm. The smallest practical drafting pen is 0.1 mm (similarly a typical inkjet technology output device can render a line as thin as 0.1 mm). If you used the 0.1 mm pen, which is inevitable, you have just exaggerated the road width by ten times. Another example of a technical limitation is that your monitor may have a color palette of 256 colors (i.e., addressed by 8-bit pixel values), where each color can be chosen from a total of 16.7 million colors (i.e., eight bits output for each of red, green, and blue); however, you may have a very limited, low-end color plotter or printer. So, regardless of how sophisticated your design on the screen may be, you are limited by the quality of your printing and plotting hardware. Mode of use Different map design treatment should be considered when you design a map to be used in a well-lit place or static location compared to one that is designed for use while driving or at lowlight conditions. Introduction 1-135

136 Communication in maps Reality Compile Cartographer // GIS specialist Recognize Select Classify Simplify Symbolize Imagine Map Mental image of of reality Map Read Analyze Interpret Map user Map The cartographer or GIS or CAD specialist This person compiles the data from several sources. Perhaps they have visited the place they are about to map. After recognizing what data is necessary for the map, they select only the data necessary to fulfill the map objective. The cartographer or GIS or CAD specialist takes what is selected, classifies the data into fewer categories, simplifies it, and finally selects the proper symbology for displaying the information on the map. The map user This person takes the map, reads the symbology, analyzes the relationships, and interprets the information depicted, whether through conclusion or inference. They acquire a mental image of the area that they may not have seen before. Their conclusions or inferences are based solely on the symbology presented in the map. As a cartographer or GIS or CAD specialist, this makes your symbology selection and map design critical issues in the communication process between you and the map user. The communication channel Imagine giving directions on the phone for someone who has never been to your area. You tell that person to go on this highway and use that exit, then turn left on such a street, and finally the house is the fifth one on the left. You have selected only what you consider important in giving directions. You have excluded all other details or landmarks. While listening to you, and perhaps taking notes, the other person on the phone is building a mental image of your description. That person will never re-create the same exact mental image as yours. Introduction 1-136

137 Types of maps General maps Locational/positional Variety of features and uses Soils Population Thematic maps Distribution of an attribute Single attribute or relationship Qualitative Quantitative Different objectives, different cartographic designs Classifying maps Classifying maps is a difficult task, but you can generally divide maps into two categories: general and thematic. General maps General maps show locational or positional types of data. They depict a variety of features and are used by many disciplines. This is why they are considered general. Examples of such maps include atlas maps or topographic maps produced by the United States Geological Survey. Thematic maps There are two types of thematic maps: qualitative and quantitative. Both show the distribution of an attribute, and both generally depict a single attribute or relationship. It is not unusual, however, for more complicated thematic maps to have several attributes or relationships. Qualitative thematic maps These maps depict data such as different soil types and different types of features with equal importance at a nominal scale. Some qualitative maps change to a quantitative classification if you change the scale from nominal to ordinal (e.g., showing a relative fertility index or a water retention index for different soil types). Quantitative thematic maps Here you are deliberately showing differences in quantitative characteristics. You are using an interval or ratio scale to show such things as population density per square kilometers or variation in temperature or humidity. Introduction 1-137

138 Issues in cartographic design Colors, shade patterns, and text Perception of colors and symbols Legibility of features and text Visual contrast and hierarchy Size Value Visual balance Eyes have limitations Number of colors and shades: Research has shown that the human eye is limited in its ability to decipher differences between colors if more than twelve colors appear together. Additionally, if you decide to use different shades of the same color, you need to realize that the human eye can decipher no more than seven or eight distinct shades. Legibility Legibility is defined as the smallest symbol that can be easily read at a certain distance. Many maps fail to relay useful information because the text, point, or line symbols are too small. Visual contrast and hierarchy Map reading can be enhanced by increasing the visual contrast among symbols or between the symbol and its background. Variations in size or graytone value can also create a quantitative visual hierarchy. Visual contrast and hierarchy can be used in map design to lead the map reader to focus on the most important areas first and proceed next to the less important areas. Visual balance As you start displaying symbology on your map, the different treatment of graphic characteristics may result in symbols that vary in their visual weight. Strive to achieve a visual balance that enhances the purpose of the map. Introduction 1-138

139 Creating maps in ArcMap Design in Layout View Data frames organize layers Map elements are added to a virtual page Maps stored as MXD files Data location Layer properties Layout View You create your map in Layout View. Your layout may contain two or more maps (e.g., a small-scale index map and a larger-scale inset map). Each map requires adding a data frame to your map document. Data frames organize layers by similar properties A data frame is simply a frame on your map that displays layers. When you create a map, it contains a default data frame listed in the Table of Contents as Layers. You can immediately add layers to this data frame and give it a more meaningful name. Once on a map, a data frame acts like any other map element. You can change its size, move it around, or delete it. Each data frame has a projection, map extent, and scale. When a map has more than one data frame, one of them is the active data frame. The active data frame is the one you are currently working with (e.g., adding layers to it or panning and zooming). The active data frame is highlighted on the map in Layout View or is the displayed data frame in Data View. The name of the active data frame is also shown in bold text in the Table of Contents. The map document In addition to the data frames, you can add other map elements, such as the north arrow, scale bar, title, other textual information, and so on. These map elements are added to the virtual page. Later, as you finish your design, you can save your map document as an MXD file. This file stores the path names to all the data used in creating the map as well as the properties of each layer. Introduction 1-139

140 Setting up the page Remember the purpose Will the map be viewed up close or at a distance? What is the best page size? Landscape or portrait? What printer will I be using, and what are my printer size limitations? Setting up the page Page setup is an important consideration when designing maps because you are creating the canvas on which you arrange all of the map elements in your design. The page is your compositional space, and it affects most of your design decisions. Will the map be viewed up close or at a distance? The answers to the questions on the slide help you determine the size of features, symbols, labels, and other text, as well as all the other map elements that will be included in your composition. The size of your map is tied directly to its purpose. It is best to set up the page size before you begin creating the map. Keep in mind that you are working on a virtual page in Layout View. The virtual page represents the dimensions and orientation of your workspace, and eventually, your final product. By defining the size of the page first, you can visualize the composition as a whole. ArcMap lets you resize the page and, if you choose, rescale the map elements accordingly. When you right-click on the virtual page and click Page Setup, the Page Setup dialog appears. In the Page Setup dialog, you specify the dimensions and orientation of the map page, as well as printer information. Introduction 1-140

141 Identifying map elements Title Map body Legend Scale bar Designed by Committee 2004 North arrow What is missing? Other text What other map elements are missing? Scale text (1:100,000) Other text (author name, disclaimers, projection information, date of data, date of map, and so on) Logos Are all these map elements really necessary? Some map elements can be ignored if other map elements or features can substitute for it. For example, a north arrow is redundant if you have neatlines shown with coordinate labels such as latitude and longitude; a north arrow and a scale bar are both redundant if you are depicting the population of the United States in a book on United States demographic statistics; a scale bar can be redundant if neatlines are shown with the proper coordinate system and units. Avoid placing any information that does not comply with the map s objectives. These are considered visual noise and distract from effective map communication. Introduction 1-141

142 Inserting map elements (map) Legend appears 4 Drag Choose type type Modify Modify From the Insert menu, click the element you want to add. Depending on which element you select, a dialog may appear, and you can choose the element s style, color, font, and so on. Once you have made a selection, the map element is dropped, by default, in the center of the layout page. You can then use your mouse to drag and drop it to a new position on the page and resize it, if necessary. Double-clicking on an element accesses its properties and allows you to make modifications. Introduction 1-142

143 An example of the Legend Properties dialog Double-click Modify Legend tab In the Legend tab, you can change the legend title to something more meaningful or explicit (e.g., Density per square kilometer instead of the redundant Legend ). The Show check box controls whether or not a legend title appears. The title can be placed above or below the legend or to its right or left. The title properties (e.g., color, font, size) can be changed using the Symbol button. The legend symbols can be displayed using your choice of a symbol type and outline. You may choose from some predefined symbols like rectangular, elliptical, or diamond shapes, or you may create your own custom symbol. The default spacings between the individual components of the legend are set as optimum; however, you can manipulate these spacings to suit your preference. Items tab Use the Items tab to specify which legend items you want to have appear. By default, items from all map layers appear. You can also specify how you want the legend to be connected to the map: only display the legend items that have data visible on the map, add a new item to the legend when a new layer is added to the map, or reorder the legend items when the map layers are reordered. These are all set by default, but you can switch them off. Frame tab Use the Frame tab if you want to add a background shade behind the legend. Size and Position tab Use the Size and Position tab to adjust the size and location of the legend. Introduction 1-143

144 Adding a north arrow and a scale Choose type type Change angle, size, size, color Change unit, unit, increments, color, font font North arrows The North Arrow Selector offers a variety of north arrow options for your map. After selecting one, you can change its properties, such as its orientation (angle), size, and color. Scale If you have two data frames on your map, you may need to place two scales. There are three types of scales: Graphical scale bar A graphical scale bar is useful for maps that are going to be reduced in size photographically at printing. Both the main map body and the scale bar are simultaneously resized, so this guarantees the scale bar will be correct for the resized map. A scale bar allows the use of scales that may not be multiples of thousands (e.g., 1:3,475,923), which are a result of the automatic attempt of the software to try to fit the map extent of the data inside the available space in the Layout View. The Scale Bar Selector offers a variety of scale bars that you can select from for your map. After you select one, you can change its properties, such as its type, the size of each interval, the number of intervals, whether or not you want an interval to the left of the zero mark, the units, the color of the lines and labels, or the font used for the labels. Fractional scale (representative fraction) A fractional scale is what you normally use for maps that need to be published at a specified scale in multiples of thousands (e.g., 1:250,000). Once this scale is added to the map, you should not resize the map because this fractional scale is strictly text, and as you resize your map,this text string increases or decreases in text size and not in true scale value. Verbal scale An example of a verbal scale is: One inch represents one foot. Introduction 1-144

145 Incorporating a reference system Display reference positions on maps Available reference systems: Graticule Measured Grid Grid Reference Grid Grid Latitude/Longitude Map Map Units Units ABC/123 Different graticule or grid types on the same map Incorporating a reference system Graticules and grids are useful for locating features or places on a map, as both offer a reference structure. Graticules and grids are properties of the entire data frame. You can add a graticule or a grid by right-clicking on the data frame and clicking Properties. On the Data Frame Properties dialog, click the Grids tab. Then click the New Grid button, which displays the Grids and Graticules wizard. Several reference systems can be selected from the wizard. Once a reference system is selected, its properties can be changed, including changing the color of the lines and labels and the label font and orientation. You can place several different reference systems on the same map. Simply click the New Grid button, and select the reference system and its properties. This way your map can be used by many different disciplines, each using its preferred type of reference system. Introduction 1-145

146 Inserting textual information Title and author Data source, date, projection Date of map and of data Disclosures and acknowledgements same What textual information should a map have? A map may be incomplete without the following information: 1. A map title 2. The name of the author or authors 3. Projection information 4. Date of the map and date of the data 5. Sources of the data used and method of collection 6. Disclosures on whether or not you have displaced some of the spatial features for the sake of clarity 7. Acknowledgement statement, if necessary The above textual information should not necessarily appear in the same level of importance (e.g., the map title text should be larger than the projection information). Available tools In the ArcMap application, you can add text from the Drawing toolbar or from the Insert dropdown list. Introduction 1-146

147 Layout tools Zoom and pan the layout page Scale Scale remains the the same same 27% 50% 100% Additional layout settings from Tools > Options Layout View tools When you move from Data View to Layout View, another toolbar named Layout appears. The Layout toolbar has its own Zoom In and Zoom Out buttons, as well as a display of percent reduction or enlargement window (shown above in the Layout toolbar). Do not confuse the Layout toolbar s Zoom In and Zoom Out buttons with the ones on the Tools toolbar. The buttons on the Layout toolbar enable zooming in and out in order to view how the map elements look at different percent reductions and enlargements. As the monitor screen cannot show the full size of the map (e.g., a 36-inch x 24-inch map size), these buttons allow you to look at a 100-percent map enlargement. This way you have more control over your map design because you know exactly how your symbology and other elements look at actual size. Notice that as you zoom in or zoom out at different percentages using the Layout toolbar, the actual scale of the view (as inherited from Data View or as set earlier in Layout View) remains the same (shown above with 1:10,000). Introduction 1-147

148 Grids and rulers Determine the size of map elements Use guides to arrange elements Use grids to position elements at specific points Use snapping for precision and efficiency Grids and rulers How large are your map elements relative to the page size of the map? As you compose your map, you can zoom in and out to view various elements, but this capability can prove deceptive, especially when translated to printed material. It is important to keep in mind that text and other elements like north arrows and scale bars may appear legible on a large-format virtual page, but when printed, it will be oversized. The opposite is true for smaller-format maps; elements become illegible once the map is printed. Use the rulers as a reality check. Manually positioning map elements on the virtual page can be an inexact and tedious process. Snapping map elements to a ruler, guide, or grid reference point can ensure precise positioning and improve your productivity. In ArcMap, you can choose which of these visual indicators elements snap to, and you can set the snapping tolerance. You can even choose the order in which map elements snap to rulers, guides, and grids. When snapping options are defined and engaged, map elements automatically move to the nearest guide or grid point. There may be times when you want a certain map element (e.g., a data frame) to be positioned at a specific point on the map page. A grid is a series of reference points in the layout that you can use to position map elements. You can control the spacing of the grid reference points, and you can turn the grid on or off. Introduction 1-148

149 Creating and using map templates Gives all maps in a series the same look Choose a standard template ArcMap templates Create your own Creating and using map templates When you create a map series, all the maps in the series should have the same look and feel. One way to achieve this is to create a template to ensure that all the common elements in the map series (e.g., the font, background color, north arrow, legend, acknowledgements, and disclaimers) are consistent throughout each map in the series. Using a template can make you more productive and can help standardize the maps produced by your organization. Templates help maintain consistency throughout a map series. Map templates are ArcMap documents (with an MXT extension). You choose a template when you open a new map and add layers to it. ArcMap comes with a standard set of templates that you can use right away to create attractive, professional maps. You can modify the maps and the templates to suit your needs, or you can create your own templates. Like layer files, you can also share templates within your organization so that the layout of the map, the data sources, and even customization of the ArcMap interface are preserved. A standard set of templates is included with ArcGIS software. You can save a map template anywhere on your network. If you save the template in the ArcMap Templates folder, it appears in the list of templates displayed when you create a new map document. If you use a variety of templates in your organization, you can create subfolders in the ArcMap Templates folder and organize your templates accordingly. Your subfolders appear as tabs in the Select Template dialog. Creating folders in the ArcMap Templates folder automatically creates tabs on the Select Template dialog. Introduction 1-149

150 Printing and plotting maps Choose a Printer Engine ArcPress PostScript Windows ArcPress Printer Engine Printing procedure Follow the steps below to print your map. 1. From the File dropdown list, click Print. 2. In the Print dialog, point to the available printer and select the Printer Engine by clicking the Setup button. The PostScript and Windows Printer Engine drivers are available with your Windows operating system. The ArcPress Printer is a separate ESRI extension product specifically designed to facilitate high-quality map production. You choose between printer drivers in the Page Setup window. 3. On the Document Properties dialog of your printer or plotter, select the paper size and source, the number of copies, the orientation, and the color appearance. Depending on which printer engine was selected, the Document Properties dialog may be different from the graphic shown in the slide. Introduction 1-150

151 Exporting a map Export to an image format Each format has different output options Copy map to clipboard Once you have created a map, you may want to export it from a map document to an image file. The new image can then be inserted into another document (for example, Microsoft Word or PowerPoint). Export a map by choosing Export Map from the File menu. You can export maps as several types of files. Some of these formats are: EMF (Enhanced Metafiles) are Windows native vector graphics, raster graphics, or both. They are useful for embedding in Windows documents because they can be resized without distortion. BMP (bitmap) files are simple, native Windows raster images. They do not scale as well as EMF files. EPS (Encapsulated PostScript) files are primarily used for vector graphics and printing, and can be sent directly as a printer file. PDF (Portable Document Format) files are designed to be consistently viewable across different platforms. They are commonly used for distributing documents on the Web. JPEG (Joint Photographic Experts Group) files are compressed image files. They are commonly used for images on the Web because they are more compact than many other file types. Copy map to clipboard You may not need to create a new separate file for your map but only need to embed it into another document. Under the Edit menu, there is the option to temporarily store the map layout in the clipboard on your computer. Introduction 1-151