Objective: To be come more familiar with some more advanced applications in ArcGIS.

Transcription

1 Advanced Procedures in ArcGIS 2005 SPACE Workshop OSU Author: Jason VanHorn Purpose: Having gone through Getting to know ArcGIS, you are now ready to do some more advanced applications. In this lab you will deal with the creation of your own shapefile and deal with co-registering the country of Australia through the ArcGIS environment. Objective: To be come more familiar with some more advanced applications in ArcGIS. Section 1. A short history on the evolution of ArcGIS Environmental Systems Research Institute (ESRI) in was founded in 1969 in Redlands, CA. From its earliest stages, ESRI was focused on the organization and analysis of geographic data. With the advent of the personal computer in the 1980s, ESRI s focus was on the software application development of ARC/INFO. According to the ESRI website, they first developed ARC/INFO in 1982 for minicomputers and by 1986 a PC version for the personal computer was distributed. ARC/INFO is a command-line based software package that handles both vector and raster geographic data and is an industry standard tool that has been developed since the 1980s. In contrast, a much less exhaustive ESRI software package called ArcView was released in the early 1990s. Although not as comprehensive as ARC/INFO, ArcView has one major advantage over its big brother, a graphical user interface (GUI). With its GUI, ArcView has become one of the most popular GIS packages worldwide. However, by 2000, ArcView 8 was released, which was better known under its new name ArcGIS. ESRI combined many of the features of ARC/INFO into a redesigned GUI to produce an all-in-one GIS system. In addition to the ArcGIS package, many extensions are available as Add-On s to extend the software capabilities, such as through such extensions as GeoStatistical Analyst, 3D Analyst, Network Analyst, and Spatial Analyst, just to name a few. We will be using ArcGIS 9.0 in our labs during this workshop. Section 2. Essentials for lab work using ArcGIS Log on to machines To log on to the machine please use this username and password Username: space Password: space2005 File naming Although ArcGIS runs in a Windows based environment, it is HIGHLY recommended that you name all of your files as if working in a restrictive command-line environment. That simply means, that you should:

2 Never, ever, never have any SPACES in your file/folder names. Always limit your file/folder names to 12 characters or less if possible. How to save your work In the lab environment, it is essential that you stress saving your work. Often, however, when work is not saved many hours of grief and work may result. Therefore please follow the simple procedure for saving your work. A. Work on your local machine Often working across a network or to a zip drive can be very time consuming. Therefore, work on your local machine. 1. First create a folder on the c:\workspace location. 2. Name it with your surname and first initial, (e.g. jvanhorn). 3. Make sure there are NO spaces in your folder name. B. Save your work 1. Save all of your work in your newly created folder on the c:\workspace\yourname drive location. 2. Feel free to create new folders under your folder, just make sure there are NO spaces in your folder/file names. C. Copy your work to your removable drive 1. When you are finished or at a stopping point for the day, insert your Zip-disk or your memory key into the computer and copy your c:\workspace\yourname folder onto your removable drive. This will ensure that everything in your folder is copied over to the removable drive. 2. Remove your removable media and take it with you. D. Working at a new workstation 1. Now that you have all of your work saved on your removable media, for which ever workstation you choose to work on, all you need to do is copy your folder (yourname) to the c:\workspace. This will ensure all of your files are present on the local drive AS WELL AS your path names of your folders and files are the same as when you saved them. 2. When you are done working for the day at that workstation, repeat step C. Section 3. Creating your workspace Before you begin, you need to create a workspace to do all of your work in. After logging on to the computer, click Start>My Computer and navigate to the c:\workspace folder. Open the c:\workspace folder by double-clicking on the folder. Next, at the top menu bar, under the command FILE, choose NEW and make a new folder in the c:\workspace

3 folder. Name the new folder according to your name with your first initial and last name. Remember to make the name all one word. For example, jvanhorn, would be my folder. ArcGIS To open ArcGIS click Start>Programs>ESRI>ArcGIS>ArcMap. Remember that ArcMap has a Table Of Contents (TOC) on the left, a menu at the top, and a map screen on the right. ArcGIS deals with many different types of files, the most common vector files are boundary files called shape files (*.shp) and coverage files (*.cov). Basic Commands and Drawing Before moving on to digitizing, lets have a brief refresher on drawing with ArcGIS. Using the Draw toolbar (from the main menu choose VIEW>TOOLBARS>DRAW if it is not already active), create a simple drawing on the screen with the mouse. The requirements are as follows: 2 boxes 2 circles 2 lines 2 irregular polygons 2 lines of text (what ever text and font you want) These objects must all be of different colors, including different colored text. Construct a box around all of your objects (a neat line) and label at the bottom outside of your box Map 1. Put your name and date in the lower right hand corner of the drawing and SAVE the drawing. Toggle to the Print Layout View (see Appendix Image 1). Print it in Black & White. Part 2: On-screen Digitizing For this lab, we will be digitizing the country of Australia and the island of Tasmania. To do this, first you take a paper map of the area of interest and using a digitizing pad you

4 construct the boundaries. However, we will not be using a digitizing pad and instead will be doing digital on-screen digitizing. Both can be very effective, producing good results. In w:\space\2005\labs\adv_lab, please copy over the file Aus.tif to your workspace. This is a scanned map of Australia. Open ArcMap and start a new map file (FILE>NEW) and load the image using the Add Data icon, which look like this: Go ahead and click Yes to build pyramids (this will allow the display to work faster if you zoom-in or zoom-out). You will get a warning, One or more layers is missing spatial information. Data from those layers cannot be projects. Click Ok, since you already know that your scanned image of Australia does not have any spatial reference yet, it is simply just a scan. Your screen should look like Image 1 of the Appendix at the end of the lab. We will use the scanned map as our base and draw (digitize) the boundaries of Australia. First, we must load ArcCatalog. Please open ArcCatalog with the same path you used to open ArcMap. Remember that ArcCatalog is a safe environment to copy and paste ArcGIS files and is the ONLY environment you should ever copy and paste ArcGIS files in. Navigate to your workspace on the c:\ drive and select your file. With your yourname folder selected, Right-click on the file and choose New>Shapefile In the Create New Shapefile dialog box, name your file Australia and select the feature type as PolyLine. Now, click OK. Image 2 in the Appendix shows this operation. You should see your new shapefile in the catalog contents section. Drag this file into the ArcMap Table Of Contents (TOC). You will get the same warning message, One or more layers is missing spatial information. Data from those layers cannot be projected. Again choose OK. Select the shapefile in the TOC and move it above the scanned image to give it first priority. Now you are ready to digitize!!

5 Presently, your shapefile is just an empty vessel waiting to have something put in to it. So let s digitize some lines and give the shapefile a shape! To edit and digitize your shapefile, you must load your Editor toolbar menu (VIEW>TOOLBARS>EDITOR). Make sure your shapefile is selected in the Table Of Contents and from the Editor Toolbar choose Editor>Start Editing. Now you can make edits to your shapefile. Your Editor tool bar should look like this: So as our Task, we are going to create a new feature and we are going to do that on the target file Australia. Notice the Pencil icon. This is the Sketch tool we will use to digitize our boundaries. Before we do that however, we are going to set a tolerance level for what is called snapping, which will help us out tremendously. Go to Editor>Options and under the General Tab, change the Snapping Tolerance to 30 pixels. Click OK. Now under Editor>Snapping, check mark the three boxes next to Australia (Boxes Vertex, Edge, & End. Make absolutely sure you checked the correct boxes. If you need help finding the boxes, let me know. Close the Snapping contents box. Now we will use the sketch tool. Notice there are 9 different sketch options from the dropdown arrow next to the sketch tool. They look like this: We will only be working with the Sketch tool on this lab. Select the Sketch Tool. Move into the Map area and you will notice the tool has a cross-hair and blue circle. This will help you to pinpoint exact map locations. At this point you are much too far away to accurately sketch the boundaries of Australia, so you must zoom in. To do this you can use the Z key to zoom in. Hold the Z key down and you will see that you can zoom into a specific area. To zoom out, use the X key and to pan around on your image, use the C key. Try zooming-in, zooming-out, and panning. Now zoom into an area you

6 want to begin tracing the boundaries of Australia. Do one Australia division at a time. Left click to set a tic point and continue until all of Australia is digitized. To finish off a division, Left-Click on the first tic point you set (Make sure you zoom-in to correctly select it) then after you have connected the tic points, Right-Click and choose finish sketch. You may need to reference a map of Australia to follow the boundaries more accurately and don t worry about digitizing the little islands for this lab. But DON T forget about Tasmania, you must also digitize that as well. If you mess up, you can always choose to delete sketch by Right-Clicking or to delete your last vertex by hovering your cursor over the vertex and Right-Clicking and choosing Delete Vertex. After you have finished all of your digitizing, save your edits under Editor>Save Edits. Then you stop editing by choosing Editor>Stop Editing. Register Your Digitized Map Now we must take your map and register it to real world coordinates. In ArcCatalog, copy the file aus_polygon from w:\space\2005\labs\adv_gis (If you don t see the w:\ drive in the ArcCatalog TOC you may need to Connect to New Folder as shown in the Appendix Image 2) to your workspace drive. Switching over, in ArcMap, start a new Map file (FILE>NEW). Load the aus_polygon layer using the Add Data icon. Notice in the lower right corner, as you move your cursor around the Map screen, you seen Latitude and Longitude coordinates. Since your digitized map does not have correct coordinates, we are essentially going to drape your digitized shapefile over the aus_polygon layer to set the projection and coordinates correctly. Now load your digitized shapefile, Australia using the Add Data icon. Click OK about the different projection warning. Now click the Globe icon on the Tools toolbar and you will see both your digitized Australia and the correctly projected aus_polygon layers. Now we are going to perform the draping by applying a mathematical algorithm called an Affine Transformation, which will translate, skew, rotate and resize our digitized

7 Australia into the coordinates system of aus_polygon. To do this load the Spatial Adjustments toolbar from VIEW>TOOLBARS>Spatial Adjustment. Select your shapefile layer that you created in the TOC and then start editing (Editor>Start Editing). Now you can do the transformation on the Australia layer. From the Spatial Adjustment dropdown layer choose Set Spatial Adjustment. Make sure your selection look like the following: Did you choose All feature in these layers? Was only Australia checked? Now click OK. Next make sure that under Spatial Adjustments>Adjustment Methods> Transformation Affine is selected. Using the New Displacement Links from the Spatial Adjustments toolbar (See the icon circled below) you will connect from one location on the Australia shapefile to its corresponding point on the aus_polygon layer NOT VISA VERSA. Use the combination of Z, X, and C as you did before to zoom and pan. You should have no fewer than 35 Displacement Links between the shapefile and the aus_polygon. Try and make a systematic pattern placement with your 35 links. With at least 35 links, now you will apply the Affine Transformation. You can do this by selecting Spatial Adjustment>Adjust. You should now see how well you did in your

8 adjustments. Continue to make additional adjustments if you need to, by following the same procedure as before. When you are done, save your edits and stop editing. Print a hard-copy color image of your shapefile draped on top of the aus_polygon to see how well you did if you want a hardcopy record of your work. Accuracy is very important. Refer to Appendix Image 1, to see how you switch from the Map View to the Print Layout View if you do not remember. Now lets apply a geographic coordinate system to your shapefile. Open up the Toolbox Icon on the main menu, which looks like this: Select by double-clicking, Project under ArcToolbox >Data Management Tools> Projections and Transformations>Feature and you will see a dialog box pop up. Now we will project the shapefile into the same coordinates as the aus_polygon. From the 1 st dropdown, select your Australia shapefile. In the second dropdown, make sure that your output is being saved to your c:\workspace location. Name the output, Australia_Projection.shp. Now click the Spatial Reference Icon (Circled below). In the Spatial Reference dialog box, choose Import and then choose the aus_polygon file in your c:\workspace location. Click Ok & Ok and you should see the toolbox do some work. The output Australia_Projection shapefile is now correctly projected into geographic coordinate space! Good Job

9 Making The Final Map Now it s time to make your final map. Open a new Map File (FILE>NEW). Now in ArcToolbox choose ArcToolbox >Data Management Tools> Projections and Transformations>Project and project the Austrial_Projection shapefile into a better choice than just lat/long coordinates. Now add your Australia_Projection shapefile using the Add Data icon. Notice the coordinates should now be corrected in the lower right corner. Now switch over to the Print Layout View. From the main menu, choose Insert and you will see many different options to enhance your final map. Refer to the Help Menu off the main menu if you need help. You must include a: the title like Base Map of Australia (36 point font) Legend North Arrow Scale Bar (in miles) Neatline The cities of: Adelaide, Mt. Isa, Brisbane, Cairns, Canberra, Darwin, Perth, Melbourne, Albany, Sydney, Hobart, and Broome. (Utilize the Draw toolbar to place your cities. Be aware of your coordinates and the placement of your cities) or if you are really hankering for a challenge, create another shapefile based on the lat/long of the cities if you want help with this I can help you. Include the text names of each city (12 point font), names of Australian states including Tasmania and the National Capital Territory (16 point font), and your name and date in the lower right corner (12 point font). That concludes this lab. Well done! If you have any questions or suggestions, please let me know.

10 APPENDIX Main Menu Image 1. Table of Contents Tool Menu (VIEW>TOOLBARS> TOOLS) Toggle between Map View and Print Layout View Image 2. Scanned Image Connect to new folder Dialog Box c:\workspace\yourspace