Chapter 5 Tasks

Week 3 Lab: Spatial data editing and vector data analysis

Finish all tasks in Chapters 5 and 10, except for Task 5 in Chapter 5 (See the supplemental instructions of Task 5 for details). Answer and submit all questions listed at the end of this exercise.

Supplemental instructions:

Chapter 5 Tasks

Task 1: Correct Topological Errors in ArcInfo Workstation

Note:

The “/*” tells you that the following text is for your information and is not a part of the command.
To get help with commands, you can open Start/Programs/ArcGIS/ArcInfo Workstation/ArcDoc.
To zoom in to a smaller extent, type mapextent *. You can then use the cursor to click and drag the extent you want. You’ll then have to tell it to ‘draw’ again.
To view the tolerances, type ‘tolerance editmap1 list’.
The Clean command uses the fuzzy, tic match and dangle tolerances. If you want to play with these and try changing them, type something like ‘tolerance editmap fuzzy 0.009’.
To copy some or part of the commands you have been using, click on the icon in the upper left corner of the Arc command window, and select Edit, and then Mark. A grey cursor box will appear in the upper left of the command screen. You can click once to bring it to where you want to begin copying, then drag to the extent you want copied. Click the upper left icon again and select edit and copy. Now you can paste it to a Word document for future reference.

Step 1: Change the Arcedit command ‘drawenv arc node errors label’ to ‘drawenv arc node errors label ids’.

Step 7: The command ‘save’ will save your changes. Then use the command ‘clean’, then ‘build’.

Task 2: Perform Edgematching in ArcInfo

Add Step 3.5) Press the Draw Environment button and check nodes, then Apply. In the Index window under Pan/Zoom, select Redisplay. In Step 4, be sure to zoom in very close.

Step 8: View qandq in ArcMap, mot in Arc.

Task 3: Edit a Shapefile in ArcMap

Step 5: Check that no more polygons than polygon 71 are selected. I had to open the attribute table to select only polygon 71.

Step 6: From the Editor drop down menu, select More Editing Tools, then Topology. Press the Map Topology button, and check editmap2, and press OK. Select the Topology Edit tool from the Topology menu. Select the polygon you want to edit by left clicking the edge. Right click and click Select Shared Features. Now double click on the polygon to see the vertices. Continue following the text instructions.

Task 4: Integrate Map Features in a Feature Dataset in ArcMap.

Replace Steps 5-7 with the followings:

Open ArcToolBox window and double-click the “Integrate” tool in the “Data management tools -> Feature class.” Select both landuse and soils as input features. Set the rank of soils to 1 and landuse to 2. Enter 5 (meters) as the cluster tolerance. Click OK.

After the process finished, add landuse.shp and soils.shp into the data frame in ArcMap. Change the symbology of these two shape files to hollow and use different colors to distinguish these data layers. Use the check box of each data layer to turn on/off the display and examine what integrate has done on the landuse and soils data in the geodatabase. Make notes to yourself how ranks affect the output and the problems of using the integrate tool.

Task 5: Edit a Coverage in ArcMap

ArcGIS 9 no longer supports coverage topology. You need to use the procedures described in Task1 to edit the coverage or convert the coverage into a geodatabase feature class and, then, follow the procedures described in Task3 to edit it.

Chapter 10 Tasks

Task 1: Perform Buffering and Map Overlay

Step 1: Before you can begin, you will need to add the Buffer Wizard to the Tools menu. For directions, select ArcGIS Desktop Help from the Help menu from the ArcMap menu bar. Type the keyword ‘buffer’ into the index search window. Select Adding the Buffer Wizard to the Tools Menu, and follow the directions given.

Step 3: The geoprocessing Wizard, with capabilities to dissolve, merge, clip, intersect, and union, no longer exists in ArcView 9. These functions are now available in ArcView 9 as tools within ArcToolbox. The table below shows the location of the Geoprocessing and Buffer Wizard functions in the ArcView 9 geoprocessing environment.

ArcView GIS 3 Geoprocessing and Buffer Wizards functionality	ArcView 9 ArcToolbox
Dissolve	Data Management toolbox > Generalization toolset > Dissolve tool
Merge	Data Management toolbox > General toolset > Append tool
Clip	Analysis toolbox > Extract toolset > Clip tool
Intersect	Analysis toolbox > Overlay toolset > Intersect tool
Union	Analysis toolbox > Overlay toolset > Union tool
Buffer	Analysis toolbox > Proximity toolset > Buffer tool
Multiple Ring Buffer	Analysis toolbox > Proximity toolset > Multiple Ring Buffer tool

Task 2: Use a Visual Basic Script to Update Area and Perimeter of a Shapefile

After the Microsoft Visual Basic window appears, you can press F1 to open the help document. Type “Dim” and select “Dim statement” to view how this statement works. In VBA (and most computer programming languages), you need to declare a variable before you can use it to store the information for later use. Sometimes variables can be declared as object types. For example, the Iarea and Icurve are object types defined in ArcGIS.

In VB window, select “Object Browser” from the “view” pull-down menu. In the object browser window, change “All library” to “esriGeometry” and type “ipoint” in the space below. Then, press “enter”. Click “Ipoint” in the column with the “Class” heading. You will see in the lower panel a list of properties, functions, and subroutines associated with the ipoint class. Click on each entry to see its descriptions that are shown at the bottom of the window.

Chapter 5 questions:

1) What does the command ‘mapex’ do?

2) What does the command ‘editcov’ do?

3) If you have the chance to redigitize the map used in Task1, then what would be the strategies to minimize the efforts spent in manual editing? Hint: Consider the types of topological errors that can be fixed with global correcting methods (e.g., CLEAN).

4) What is a Feature Dataset?

5) What are some advantages of creating a feature dataset in a personal geodatabase, as opposed to just creating a set of shapefiles?

6) What is the difference between a fuzzy tolerance and a cluster tolerance?

Chapter 10 questions:

1) Dim is a VBA statement to declare variables and allocates storage space for these variables. List four numeric data types that numeric fields can have and describe each. (You may need to use the VBA Help in ArcGIS.)

2) Ipoint is an object type used as an interface to access the geometry of point objects. List all numeric properties of the ipoint class and describe what they are.

3) Many geometric data, such as the x, y, and z coordinates of a point, cannot be directly accessed. If you need these data, using VBA scripts is one simple way to get them. Write the VBA script that extracts the z values of a point shape file. (Hint: Open the ArcGIS Help and search for “VBA” documents. Read the section of “using in field calculations”.)

4) Give an example of how the “join data by location” technique can be used in GIS data compilation.