GEOG 4/575 Lab 5: Raster and Terrain Data Manipulation

 

Due Nov 4 (Friday) by 5PM.

 

DEM (Digital Elevation Model) is a type of raster data. You will use DEM to create contours, vertical profile, hillshade, and other derivative surfaces such as slope and aspect. You will also learn how to build a TIN using a DEM.

 

            Finish all tasks in Chang’s Chapter 14. If you have not had GIS II, it would be a good exercise to also do Task 3: Convert Vector Data to Raster Data in Chapter 5. Answer and submit all questions listed at the end of this exercise. Lab exercise data are available in: I:\Students\Instructors\Geoffrey_Duh\Chang_3e\chap5 and 14 (or on the textbook CD). Please copy all these folders to your working directory in c:\temp before you start.

 

Additional note:

  1. Task 2, Step 2. You will have to select “Equal Interval” for classification method first, before you can change the number of classes to 5.
  2. Task 3, Step 3. Don’t use the Edit TIN tool in Arctoolbox, instead, use the “Add Features to TIN” in the “Create/Modify TIN” submenu of 3D Analyst’s pulldown menu.

 

Questions:

1)      Use ArcCatalog to find the header information of the DEM, plne, that you used in Task 1.

Raster Data Format

 

Planar distance units

 

Vertical Z units

 

Cell size (x, y)

 

Number of cells on x (column), y (row)

 

Data type of cell

 

Number of bits per cell

 

 

2)      There is a conversion tool called “Features to 3D” in ArcGIS 3D Analyst’s pulldown menu (in the convert submenu). It assigns z values to features in a GIS layer using the values from a DEM. Use this tool to convent the contours (i.e., ctour.shp) into a 3D shapefile. How could you tell the output features are 3D features?

 

3)      You have a DEM and a shapefile containing the locations (i.e., points) of weather stations. How could you find the elevations of these weather stations? (Hint: Either check the tools in the “Spatial Analyst Tools-Extraction” toolset or the “Add XY Coordinates” tool in the ‘Data Management Tools-Features” toolset in Arctoolbox.)

 

4)      What are the azimuth and altitude refer to in Task 1, step 1.3?

 

5)      What’s the total area (hectare) for areas with a slope > 40 percent?

 

6)      Describe the effects of “Add Features to TIN” on TINs you created in Task 3, Steps 2 and 3. Also report the numbers of nodes and triangles in both TINs.