Geographic Information Systems: GHY 417/517 Instructor: Bandana Kar Teaching Assistant: Jake McKee Office Hours: MW 9am – 12pm, WSB 213 DUE DATE: Thursday, October 1 LAB: ON-SCREEN DIGITIZATION OF POINTS, POLYLINES AND POLYGONS OBJECTIVES This lab will introduce you to 1) On-Screen Digitizing of Points, Polylines and Polygons in Arc Map 2) Symbolizing a legend to see Unique Values 3) Layout basics 4) Creating Metadata * Your final goal is to overlay the outline of Lake Murray and recent roads on the RectifyMurray.sid image in order to see what areas were inundated with the creation of the lake and where the current roads are in relation to previously settled areas. MATERIALS The datasets you will be working with are located on the server. Copy the zip file named “Lab5_Data” from http://gg.usm.edu/kar/Course_417_517.htm into your C:\Temp folder. Coverage Name Image Files Rectifymurray.sid Description Registered scan of the Columbia 1904 30‟ Quadrangle. USGS 7.5‟ Topographic Quadrangle USGS 7.5‟ Topographic Quadrangle USGS 7.5‟ Topographic Quadrangle USGS 7.5‟ Topographic Quadrangle USGS 7.5‟ Topographic Quadrangle
Chapi71.sid Irmo90.sid Lamea71.sid Lamwe71.sid Littm71.sid Shape Files aoi.shp
Area of interest for digitizing the roads
Task 1. Introduction to ArcCatalog and Metadata
Open ArcMap and ArcCatalog In ArcCatalog, navigate to the folder C:\Temp\ lab5. o If the network drive is not already connected: In ArcCatalog, select File Connect Folder Navigate to “C:\Temp\ lab5” Click OK
Task 2. Create a New POINT Layer
In ArcCatalog make sure the Contents Tab is your active tab Right click in the Contents area Select New Shapefile o In the Create New Shapefile dialog box Change Name to YOURLASTNAME_Point Leave the Feature Type as Point Click OK Your new shapefile should now be located in the Contents area Minimize ArcCatalog
Task 3. Preparing the Project
Add the image layer “rectifymurray.sid” to a Data Frame in Arc Map Go to View Data Frame Properties, and set Map units to meters and Display units to miles In your data frame, set your Map scale to 1:64,000 Right click on the image layer, select Properties Symbology RGB Composite to change the appearance of the image on ArcMap. Play with the changes, but do not use the changes for digitization.
Task 4. Digitize Points in ArcMap
In ArcMap, add the new point shapefile you created. o Select View Toolbars. o Make sure the Editor Toolbar is checked on. You are now going to digitize the ferries along the Saluda River in 1904, and list their names as one of the attributes in the attribute table. Before adding points to your shapefile, we must add a Name field to the attribute table that will store the ferry names. o To do so, right click on the point layer “Yourlastname_Point.shp”, and choose Open Attribute Table o Using the Options Button, choose Add Field o In the Add Field Dialog Fill the first blank with Name Type should be changed to Text Length can be left at 50 o Click OK o Close the Attribute Table To add points to your shapefile: o On the Editor Toolbar, click the button labeled Editor. o Click Start Editing Your Editor Toolbar should now be active. o Make sure the Task is set to Create New Feature and the Target is YOURLASTNAME_Point.
o Using your Zoom tool, zoom to the lower left area of the rectifymurray.sid, centering on the Saluda River. o Using your Pan tool, find the first ferry on the Saluda River from the left. The first ferry is called “Holly’s Ferry” o Click on the Pencil (Create New Feature Tool) o Click once where the road intersects the river – a new point should appear o Open the Attribute Table, and in the first Name record, type Holly‟s Ferry Notice that what you are doing is a Heads up Digitizing process, as discussed in class. The other option to create a spatial data of the ferries would be to use a digitizing table (Heads down Digitizing), a more burdensome and time consuming process. o Unselect the selected point by clicking on OptionsClear Selection. o Move the Attribute Table out of the way, and continue adding points along the river where the ferries are found using your Pan Tool and Create New Features Tool. Note: After adding each point, type the name of the ferry into the attribute table and unselect the selected point. Notice that if you get another dataset with additional information about the ferries, the name of the ferry could be used as your Key field for joining. Make sure you type the name correctly. o When finished, close the attribute table, and on the Editor Toolbar, click the Editor Button o Choose Stop Editing, and click Yes to save edits.
Task 5. Create a New POLYGON Layer
Open ArcCatalog Navigate to the folder “C:\Temp\lab4” Right click in the Contents area Select New Shapefile or click on File New Shapefile o In the Create New Shapefile Dialog o Change Name to be YOURLASTNAME_Polygon o Change the Feature Type to Polygon o Click OK o Your new shapefile should now be located in the Contents area Minimize ArcCatalog
Task 6. Digitize Polygons in ArcMap
You learned how to create points using a scanned map as the reference. Now you will learn how to accomplish a similar task for polylines and polygons. While creating your polygons, keep in mind the potential spatial generalization mistakes that may happen, and that you should try to avoid (e.g. fusion, simplification, exaggeration, etc). Add all the layers except the image layer “rectifymurray.sid” to a Data Frame in Arc Map Make sure the Editor Toolbar under View Toolbars is checked on.
In ArcMap, add the new polygon shapefile you created to your data frame Add a field to the polygon shapefile. o In the Add Field dialog Enter Name for Name field Change Type to Text In Field Properties change Length to 50 o Close the attribute table You are now going to digitize a ROUGH outline of Lake Murray. To add polygons to your shapefile: o Click Start Editing on the Editor Toolbar o Your Editor Toolbar should now be active. o Make sure the Task is set to Create New Feature and the Target is YOURLASTNAME_Polygon. To begin adding features o Using your Zoom tool, zoom to the lower left area of your data frame, centered on Lake Murray o Click on the Pencil (Create New Feature Tool) o Begin tracing the lake by left-clicking on each point. o Green vertices should appear o To pan or zoom while digitizing, just click on the tool that you want to use o Click back on the Pencil tool to continue editing o When finished, double click! DO NOT DOUBLE CLICK IN THE MIDDLE OF DIGITIZATION IF THE ENTIRE LAKE BOUNDARY IS NOT YET COVERED. THIS WILL CREATE A NEW POLYGON. The lake should now be color filled Choose Stop Editing on the Editor Toolbar to stop the editing process, and click Yes to Save Edits. Make the outline of the Lake thicker and the center hollow by changing Symbology for the layer. If after double-clicking you feel like you made a mistake, and the polygon does not accurately reflect the feature you are digitizing, remember that editing is one of the functions of GIS. You can always change the number and the positions of the vertices you created. To edit a polygon: Start Editing should be selected. Make sure the Task is set to Modify feature and the Target is YOURLASTNAME_Polygon. Use the pointer arrow in the Editor Toolbar to select the polygon. Once selected, the vertices of the polygon you digitized should appear on the screen. To change the vertices: o Move the pointer arrow on to the vertex you want to move or change. o When the pointer arrow turns into a green square, click on that vertex and drag it to another position. In order to make the outline of the polygon smooth, precise and accurate, more vertices should be inserted. To insert a new vertex,
o Move the pointer arrow on to the outline of the polygon, right click, and then select Insert Vertex. To delete a vertex, o Move the pointer arrow to the specific vertex o Right click and select Delete Vertex. o Other than deleting, you can also check other options you get. After digitization is over for Lake Murray, enter the name of the lake in the Name field of YOURLASTNAME_Polygon shapefile‟s attribute table. Choose Save Edits in Editor Toolbar if you are not done with modification, Finally select Stop Editing and click Yes for the prompt “if you want to save edits”.
Task 7. Digitizing POLYLINES “roads” in ArcMap
In ArcCatalog, create a polyline shapefile with the following instructions: o Name: YOURLASTNAME_roads o Feature Type: Polyline Add the new shapefile into ArcMap Select Create New Feature on the Editor Toolbar and set the Target to YOURLASTNAME_roads. Zoom to the aoi.shp layer Re-symbolize the aoi.shp to be simply an outline Set the editing environment by: o On the Editor Toolbar, navigate to Options o Under the General Tab, set Snapping tolerance to 5 pixels. o Click OK o On the Editor Toolbar, select Start Editing o Navigate to Snapping o Check ALL boxes next to aoi o Check ONLY the „edge‟ box next to YOURLASTNAME_roads. o Close the box. o Digitize all the roads within the boundary of aoi.shp o Notice now the pencil tool will automatically snap to the aoi.shp boundary when you move the cursor close enough (i.e. within the tolerance of 5 pixel distance). Save your work
Task 8. Creating a NICE Map
Rename YOURLASTNAME_point to appropriate labels and superimpose the data on RectifyMurray.sid. Create a map using these two layers. Rename YOURLASTNAME_polygon, YOURLASTNAME _roads and aoi.shp to appropriate labels. Create another map with the outline of Lake Murray and new roads superimposed over the layers used for creating these layers. Include the cartographical features: o North arrow
o Scale o Title o Legend o Cartographer o Date of Source Materials o Name of the author Note: Make sure all of the above features can be easily seen on your map, and are arranged in a NICE manner. Pay attention to the gray tones and colors you use. Print your map Save your work as a “.mxd” file. To work on the map later, remember to move the lab4 folder including the data and .mxd file from C:\Temp to your harddrive.
Task 9. Creating Metadata(i.e. data about data)
Metadata stores all the information about how the spatial and non-spatial data was created. Open ArcCatalog Click on YOURLASTNAME_POLYGON.shp Click the Metadata Tab In the upper left corner of ArcCatalog, change the Stylesheet to Federal Geographic Data Committee (FGDC) Click the Edit Metadata button Using ArcCatalog, please fill in the following in the Metadata dialog box for the YOURLASTNAME_POLYGON.SHP: Identification: o General Abstract – a brief description of the dataset Purpose – a summary of what the data can be used for Contact: o Details Person – creator (you) Organization – who you are working for Position – occupation Citation o General Title – title of the shapefile Originator - creator Publication Date – date of data creation Time Period o Change Currentness Reference to publication Date o Calendar Date – date of metadata creation Data Quality: o Process Step
Process Description – type a paragraph of all the steps followed to create the shapefile. This should be a detailed description of what we did in lab. Please include where the files originated from.
_____________________________________________________________________________ GHY417/517 Due: Thursday, October 1 Lab: Onscreen Digitization Name:________________
1. A copy of your maps that includes the important cartographic elements (e.g., neat line, title, legend, scale bar, author, north arrow, etc.) 2. Zip your polygon shape file(s) and send to me by October 1st with added metadata. You must provide your unique digitized version.