BIO8014 GIS & Remote Sensing Practical Series. Practical 1: Introduction to ArcGIS Desktop

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1 BIO8014 GIS & Remote Sensing Practical Series Practical 1: Introduction to ArcGIS Desktop 0. Introduction There are various activities associated with the term GIS, these include visualisation, manipulation and analysis. In completion this course you will be exposed to all of these and you will finish the course as a competent GIS user. The module will focus on ArcGIS for Desktop as this is probably the most widely used and stable GIS software. It is a vast and powerful programme but it will not take you long to understand the basics as well as gain the ability to locate the specific tools you require to solve any spatial problem. The world of GIS software can be a little confusing so it is worth making clear the two main programmes you ll be using. ArcCatalog ArcMap Regardless of which ArcGIS for Desktop setup is purchased from ESRI ( you ll receive these two programmes, under the general description of ArcGIS for Desktop. At Newcastle University ArcGIS for Desktop was installed in most PC clusters in August 2015, although some may still have The practical notes should work with both versions. What you will achieve by the end of Practical 1 1. How to attach folders and list different types of map in ArcCatalog 2. How to import spatial data from Excel into GIS format using ArcCatalog 3. Basic use of ArcMap to display maps 4. How to create a new map in ArcCatalog and digitise it in ArcMap to show your route from home to University 5. How to add new attribute fields to your map to calculate your distance and average speed in ArcMap Data for these practicals Create a new folder on your own H: drive (this is your Documents folder) and call it BIO8014 Download the file Practical 1.zip from Blackboard (right-click and select Save link as Save Practical 1.zip in your new BIO8014 folder on your H: drive. Do NOT save it to your Desktop. Inside your BIO8014 folder, right-click on Practical 1.zip, then select 7-Zip and select Extract Here (Do NOT use the default Open or Extract All options as they have a bug and corrupt ArcGIS files) This will create a folder named Practical 1 with a number of GIS files in it. Finally, delete the Practical 1.zip file to save disk space Page 1 of 28

2 1. Introduction to ArcCatalog This application is similar in format to Windows Explorer, in that in enables the user to locate, browse and manage their spatial data. When undertaking any GIS work it is good practice to first open ArcCatalog. Even though the geoprocessing tools can be opened from here, it s not recommended that you undertake data manipulation or analysis here but use it for file management, if you wish to create or delete spatial data, always do it here. Launch ArcCatalog; Start All Programs ArcGIS ArcCatalog (Note that the exact menu selection to reach ArcGIS can vary slightly between cluster rooms). If any warning messages popup when opening simply click OK. Once the programme has launched you should see the following window. As you can see it takes a similar format as Windows File Explorer, with the catalogue tree down the left and a main viewing frame with three tabs labelled; Contents, Preview and Description. Unlike Windows Explorer few, or no, folder connections are listed in the catalogue tree, therefore you have to create the links to your working folder and any subsequent folders you wish to create. To do this click on the second icon from the top left (when your mouse hovers over it, it should display the name Connect To Folder), which looks like this: Page 2 of 28

3 In the popup window navigate to where you have created your GIS working folder, highlight it through one mouse click and then click OK. Within the catalogue tree you should now see the full link to your working folder, e.g. In the viewing frame you should see the contents of this folder (if not check that the tab at the top is selected to Contents). There are 3 items listed in this folder: an Excel File, an ArcGIS File Geodatabase, and an ArcGIS Map Document. Observe the icon associated with this file. This icon is part of a unique set of icons which ArcCatalog uses to identify spatial and other specific file types used within ArcGIS. You will get to know these well. Now double click on the Journeys File Geodatabase. You should see the following seven files. Page 3 of 28

4 Here you are introduced to two further geographic file types specific to GIS. They are feature classes and rasters. The feature classes include vector maps Home_and_work, Route_to_work and Water_features. The four raster files contain GIS data from the British Ordnance Survey: in this practical we will use them to provide a backdrop. You see that ArcCatalog has identified one File Geodatabase, containing seven sets of geospatial data. Next open Windows Explorer: Start All Programs Accessories Windows Explorer and navigate to the folder where these seven GIS data types are located. How many files do you see? Are you surprised by the number of files you see? Even though ArcCatalog lists only seven files present in this folder it is clear from Windows Explorer that there are many more. A GIS map stores shape, projection system, attribute data etc. which cannot all be stored in one file, therefore many files are required. It is not important for you to know exactly what each file does, but be aware that if any one of these files is deleted then it will corrupt your GIS map. It is essential that you only use ArcCatalog when creating, moving and deleting spatial datasets, otherwise you could damage your GIS maps. Close Windows Explorer and return to ArcCatalog. Expand the Journeys File Geodatabase within the catalogue tree on the left of ArcCatalog and click once on the Home_and_work feature class. In the view frame click on Preview tab and you should see two points present. This is showing you the geographic component of the vector Feature Class; now repeat this with the two other vector files present Route_to_work and Water_features. You should now have an idea what the three vector types look like. (Ignore the four Raster files for now). Reselect Home_and_work and then in the drop down box at the bottom of the view frame select Table. This now enables you to see the attributes associated with each feature within the vector dataset. As you will learn from in the lectures, GIS is not simply a graphic tool, but a powerful database. The table you should now be viewing contains attribute information about each feature within the File Geodatabase, each line in the table represents one spatial feature. Within the Home_and_work Page 4 of 28

5 dataset you saw that there are two points present, hence there are two rows of data in the table, one for each point. What do the two points represent? The Home_and_work and Route_to_work vector datasets were created specifically for this course and are relatively simple, the third vector dataset Water_features is extracted from a highly complex dataset called MasterMap created by Ordnance Survey. Select the Water_features dataset within ArcCatalog and take a look at the table, you will see that there are numerous attributes associated with each feature, some attributes are easy to understand, such as shape and shape_area and others which are not so clear. This is something that you will have to get used to when using spatial data, as you will undoubtedly be receiving datasets from many sources and they will range substantially in both their quality and complexity, you will also learn which attributes are relevant to the task you have at hand and which are not. Now click in any one of the boxes within the attribute table, it will become highlighted. Now try and type something - nothing happens. This is because you have limited editing of a dataset here in ArcCatalog. It is only possible view, move and delete complete files. With the Water_feature dataset still selected, switch back to the Geography view. You should see a series of tools in the menu area become active. We are going to have a look at what each of these do. First select the icon with magnifying glass with a + in its centre. You now notice that your pointer has turned into that icon. This, as you probably have guessed, enables you to zoom in to a given area of the file either by clicking once with the mouse or by dragging a box around the area you wish to view. Give this a try. Now click on the icon to the right of the zoom in tool, the zoom out tool. Try it out, you see that unsurprisingly this has the opposite effect. Click now on the hand icon, this is the Pan Tool. By click and holding you can move around the file to see different areas of it. You can also zoom in and out using the scroll button on your mouse. Click the globe icon, what happens? Page 5 of 28

6 Now choose an area and zoom in to a specific feature, then select the blue i icon and click on your chosen feature. You should get a popup box which contains all the attribute information that is associated with that feature. You so far have looked at vector data, next you are going to be introduced to raster data. In the File Geodatabase are four raster datasets. nz26ne nz26nw nz26se nz26sw Each file also has the following icon next to it. This is the symbol that indicates that these are raster files. During this course you will experience two types of raster files: those which can be manipulated for analysis those which are purely for backdrop display purposes but cannot be analysed. These four datasets here are the latter. They are produced by Ordnance Survey and they are a part of their 1:10,000 basemap dataset. Although they are produced at 1:10k scale though this does not mean that they can be only viewed at this scale. However, if you try and display a very detailed map at an unsuitable scale then your final map may not be visually clear. As you see each tile has its own unique reference number this relates to its position within the UK. If you are not familiar with the UK mapping system, grid references, eastings and northings, it is strongly recommended that you have a read the excellent resources on the Ordnance Survey website: Page 6 of 28

7 The four map tiles relate to the area round Newcastle upon Tyne. Select one of these tiles and zoom in to an area. When you see the tile as a whole, it is not possible to make out the detail as the file is too complex, though once you zoom in to a given area you can start to make out the detail. Page 7 of 28

8 2. How to convert spatial data from Excel to GIS format Navigate to the Practical 1 folder in Windows Explorer and open the Excel file Route_Points. You can see that there are two features; My home and Robinson Library. The coordinates are already entered for the Robinson Library but you need to know the coordinates for your home (if you live within the Newcastle/Gateshead city limits) or another location within the city such as the Central Train Station. Now you are unlikely to know the two six figure Ordnance Survey Great Britain of your abode therefore we have to work them out. Open the following web page; Type in the postcode of your home, though if you don t live within the Newcastle/Gateshead city limits, use the postcode of the Central train station, NE1 5DL, then click Go. A screen showing a map (with your home highlighted) will be displayed. Below the map you will see something like: Where you see the text Click here to convert coordinates do what it says and a screen similar to the following will be displayed: Displayed in the information box will be a range of coordinate information regarding the postcode location you have entered. Now the information that you require is that from top, under OS X and OS Y, so for central station it is , , this information is the easting (X_COORD) and Page 8 of 28

9 northing (Y_COORD). Enter this information next to My flat in the Excel file and then SAVE and CLOSE the Excel file. The next process is to convert the Excel data into a point Feature Class within the journeys File Geodatabase. In ArcCatalog right click on the folder Practical 1 in the catalogue tree, then click Refresh. You must do this if you alter any files outside of ArcCatalog as it will not automatically update unlike Windows Explorer. You should be able to see the Excel file you have just modified within the folder. Expand this file and you will see the separate worksheets listed. You entered your coordinates in Sheet1. Doubleclick on this and click the Fields tab in the pop-up window Table Properties and you will see the following: Page 9 of 28

10 This shows that Arc Catalogue has recognised three field names: NAME, X_COORD, Y_COORD. Click Cancel to close the Table Properties screen. Right click on the Sheet1$, then select Create Feature Class From XY Table You will get the following popup window Check that the X Field = X_COORD and Y Field = Y_COORD, if not change so that they do. This is where you will assign a coordinate system to the file, which is essential for all spatial data otherwise ArcGIS will not know how to project the data correctly. Next, click Coordinate System of Input Coordinates which will give you the following popup window: Page 10 of 28

11 Now navigate to the following folder; Projected Coordinate Systems National Grids Europe British National Grid. Click to Select it and the lower panel will now contain the details of the British National grid system. Click OK and now you will returned to the original popup. Page 11 of 28

12 In the Output section click the browse button on the right and navigate to the BIO8014\Practical 1 folder. Go inside your Journeys.gdb geodatabase, and set your dataset name to My_points. Ensure that the Save as type drop-down box is set to File and Personal Geodatabase feature classes. Note that apart from map documents all GIS files do not contain spaces within their names, this is good practice, which is recommend that you adhere to. Click Save and again you will be returned to the original popup. Click OK and you will have now created your first Feature Class. Refresh the journeys Geodatabase and you should now be able to view this new feature class: take a look at both the geographic and attribute data. Summary of Section 2: How to import spatial data from Excel to ArcGIS It is relatively straightforward to import basic geographic data, especially point (site) information from Excel files. Note that you need: Named columns for your x (eastings) and y (northings) coordinates Import from appropriate worksheet in Excel file (earlier versions of Excel may differ) Page 12 of 28

13 Avoid spaces in the filenames you use to store your ArcGIS maps Save your imported map into the appropriate File Geodatabase Set appropriate projected coordinate systems during the import process Page 13 of 28

14 3. Introduction to ArcMap ArcCatalog is for the management side for your GIS work, whereas ArcMap is where you will undertake your GIS analyses and create publication quality maps. Before you start ArcMap navigate in Windows Explorer to Practical 1 data and open up the Adobe Acrobat Document Journey to work. This is a basic example of what can be done in ArcMap. Two points have been created and then a route between them has been digitised using the Ordnance Survey data. Next it is your turn to create a similar map. In this practical you are going to create a Feature Class in journeys containing two points representing either your home or some other location in Newcastle and the Robinson library and a line Feature Class containing one line representing your journey between the two. To start ArcMap, either navigate via the start menu, or more directly by clicking the icon the menu of ArcCatalog. from Once ArcMap has launched you should see the following with the popup entitled Getting Started. Page 14 of 28

15 The popup window ArcMap - Getting Started should be offering you a Blank Map. However, you will need to set its default geodatabase to your journeys.gdb so that by default it searches and saves maps there. Browse to your correct folder before clicking OK: ArcMap has a similar layout to ArcCatalog in that the programme is split into two main windows; a table of contents on the left and the data frame viewer on the right, which are surrounded by a selection of icons relating to various actions that can take place within the application some which you should recognise from having just used them in ArcCatalog. You now need to add data to this working document. Click on the following icon. In the resultant popup window navigate to the journeys Geodatabase and select the My_Points Feature Class and click Add. Now you will see that in the table of contents under Layers is listed your dataset, with a point symbol underneath. In the data frame viewer you will see the full extent of this dataset. Now the symbol for the point is not very clear, so we are going to change this. Click once on the point symbol within the table of contents, this will give you the following popup window: Page 15 of 28

16 Choose yourself another symbol, for example Circle 2 and then click OK. You should now see in the data frame viewer that all the points within your dataset have been converted to the symbol that you have chosen. It is not possible to any idea of the location of these two points that you have created; add the Ordnance Survey 10k basemaps as raster backdrops. Again click on the Add Data icon and add the OS nz raster basemaps in a similar way. It is now possible to see where your points are in relation to the rest of Newcastle. If your second point is not located somewhere on the four basemaps this will be because you have entered your coordinates incorrectly or a location somewhere outside of the Newcastle/Gateshead city limits, if so please ask one of demonstrators to help you relocate this point. Next add two further datasets from the journeys geodatabase; Home_and_work and Route_to_work, and as before change the symbol of each feature to something that will standout, Page 16 of 28

17 with the line file increase the width to 3. Then right click on the name of the Route_to_work (not the line symbol), a little menu will appear, click on Zoom To Layer. This will centre the data frame viewer on the line file. This line file shows the route one of last year s demonstrators on this module took to work each day. In the next section you will learn how to create and edit a similar line file that shows your route from your home or central station to the Robinson Library. Page 17 of 28

18 4. Creating a blank feature class and digitising lines First you have to create a blank Feature Class from scratch from within ArcCatalog. Return to ArcCatalog, and in the catalogue tree right click on the Journeys Geodataset; New Feature Class. In the following popup window, enter the following information. Name: My_route (remember no spaces) Feature Type: Line features Click Next and then set the spatial reference system to British National Grid as you did before when creating the point file (see Section 2 of this schedule). Page 18 of 28

19 Accept defaults for other options, Preview the dataset within ArcCatalog, you will see that there is nothing present in either the geography or table view, this is because you are yet to enter any data. Return to ArcMap and add this newly created dataset. Once you have done this you should save the ArcMap map document. Click the following icon and navigate to the Practical 1 folder and save the file as My Journey, as an ArcMap Document (.mxd file). You see that in ArcMap you also have the two magnifying glasses and hand icons as you did in ArcCatalog. Use these three tools to zoom in and out and pan around to look at in detail the Route_to_work file. You can now see clearly which streets and paths last year s demonstrator walked along to get from his flat to work each day. Now it is your turn to digitise your route to work. Again using the pan and zoom tools navigate to your starting point. Next you have to add an additional menu which has a selection of editing tools. Right click in the menu area. This brings up a long list of additional menus which are accessible to you as an ArcGIS user, the one we are now interested in is the one called Editor. Find this one and click on it. This will add the following toolset (it may appear either embedded in the menu area, as shown, or floating). You will notice that most of the tools are greyed out (inactive) at the moment, this is because you are yet to start an editing session. Once you do start an editing session you are able to move individual features within a dataset and add, delete or change any features within a features attribute table. Page 19 of 28

20 On the far left-hand-side of the Editor toolbar you will notice that there is a drop-down menu called Editor. Click this once and click once again on Start Editing. The appearance of your screen will change, with two new windows on the right (the lower one, initially empty) labelled Create Features and Construction Tools, and more of your Editor toolbar buttons will now active. Click in the Create Features window on My_route and you will see something similar to: You now have the ability to alter any of the vector datasets (not rasters), though none of the changes you make will become permanent until you ask ArcMap to save these changes, so don t worry if you make any mistakes. In the Construction Tools window click on Line (default). Your pointer will have turned from an arrow to a crosshair with a blue circle in the middle, and a small toolbar Feature Construction will appear. Now click once close to your start point, be it your home or the central station, this will create the starting point of your line. Page 20 of 28

21 Now every subsequent click will create an additional node along the line. If you create a node which you are not happy with it, move the crosshair over the point and right click and select Delete Vertex. Also you will need to pan and zoom across the area in order to complete your route; you can do this while editing by pressing and holding the C key, the crosshair will then turn into the pan symbol, which will enable you to drag-and-drop the map where you wish. You can zoom in and out either by using the scroll wheel on your mouse or by press and holding either the Z (zoom in) or X (zoom out) key. Once you have reached the Robinson Library there are two ways to finish your line; double clicking, which will create a final node at that point or by pressing the F2 key, which will end the line at the last node you created. Then click on the Editor drop-down menu and click Stop Editing. You will be asked if you wish to save your edits, click Yes. Page 21 of 28

22 You have now completed your route to work. Page 22 of 28

23 5. Calculation of new attributes for your feature class As you saw in ArcCatalog, each vector Feature Class has both a geographical component and an associated attribute table. Next you are going view and add additional attribute data within ArcMap. In the table of contents, right click on the file name of Route_to_work, in popup list click on Open Attribute Table. You will now see the following. You are now going to create the following attributes for your newly created line dataset. Dist_km Distance in kilometres of the route Time_m Time in minutes your journey takes Speed_km_h The speed of your journey in kilometres per hour Close the attribute table for Route_to_work and then open the attribute table for My_route which will look roughly as follows. Click on the Table Options button at the top left:: Page 23 of 28

24 From the popup list that results click Add Field. If you get a message stating that this operation is not possible as the file is in use within another file, then close ArcCatalog. You should now be able to operate the task Add Field. You will receive the following popup. Page 24 of 28

25 Fill in the data as shown above. Name Dist_km (again no space) Type Double (double allows decimal places in your numbers such as etc.) Next click OK. You will now see that an additional attribute has been created for your line feature class. You have now created a field within the attribute table where you can calculate and store the length of your route. In the column heading for this new attribute right click and from the popup menu select Calculate Geometry. You might get a warning message about the dangers of calculations outside an edit session, ignore this and click Yes and then you will get the following popup window. ArcMap knows that you are working with a line feature class, therefore the default property that it wishes to calculate is length, this would be different if you were doing the same action with either a point or polygon feature class. Change the unit measurement from meters to kilometres, then click OK. ArcMap will now have calculated the length of the route. Page 25 of 28

26 Now as before add two further fields; Time_m and Speed_km_h both as type double. Right click on the column heading for Time_m and this time click Field Calculator. You will get the following popup window. The field calculator is a powerful tool within ArcMap which enables the user to make simple or complex calculations. The route that has been digitised for demonstration takes approximately 15 minutes to walk, therefore all that has been entered into the calculation box is 15, enter your figure for your journey, whatever that may be. Do this and click OK. You will now see that a value of 15 has been entered into the attribute Time_m. Now right click on the column heading for Speed_km_h and select Field Calculator again. This time you are going to enter an equation into the calculation box. In the Field box double click on Dist_km, then add the operator / and then double click on Time_m. This will give you the following equation; [Dist_km]/[Time_m] Surround this with brackets and then multiply by 60, to give you the following equation; ([Dist_km]/[Time_m])*60 Click OK. Page 26 of 28

27 You now have a speed calculation for your entire journey and your final attribute table should look similar to this. Close the attribute table and resave your map document by clicking the following icon again. Summary Section 5: Calculation of new attributes for your feature class Use ArcMap Field Editor to add new fields Appropriate data type for a field must be selected Calculate geometry for spatial information such as length Field calculator for simple calculations Page 27 of 28

28 Summary Practical 1 Well done, you have completed Practical 1 and achieved a great deal. You have gained the ability to view, create and understand geographical data, once you are familiar with the ArcGIS landscape all other tasks will seem easy. Key points Use ArcCatalog as you would Windows File Explorer, but it hides the numerous complex files from view to make life easier Import spatial data from Excel into GIS format via ArcCatalog Remember to refresh your view in ArcCatalog as changes are not automatic Use file geodatabases to store your spatial data ArcMap to display, edit, manipulate maps Set default geodatabase (on launch of ArcMap or via File Map Document Properties Calculate new variables in ArcMap based on existing spatial data Page 28 of 28