SO432, GIS Fall 2009

DEM Properties Lab

We will look at three DEMs.  The instructor will indicate the limitations on what you can do with this data; do not do anything with it unless you clearly understand those limitations:

• SRTM-3" (DTED Level 1) for Normandy

• IFSAR 5 m data for Afghanistan

• LIDAR 1 m data for Iraq.

You should check the help file for MICRODEM (http://www.usna.edu/Users/oceano/pguth/microdem/win32/microdem.chm) which covers all these options, and can do so before you arrive for the lab.

This lab will be entirely individual effort, and will be turned in at the end of the lab period.

Compute the storage for a one degree tile at each resolution.  You can do the computations for a latitude where the tile will be 111 km by 86.4 km, and must consider whether the elevations are stored as integers or bytes.  Also indicate which of these DEMs use geographic coordinates, and whether you think they are DSMs or DTMs.

Provide graphic examples for each of the following products, and write a sentence or two on the utility of each. Insure that you have two graphics from each of the three DEMs.

• Slope map.

• Aspect map

• 3d Anaglyph map

• Topographic profile/line of sight

• Weapons fan/viewshed

• OpenGL 3D view

• Contour map (both overlaid on shaded relief, and as a separate map).

Provide a map showing the locations of minarets in the city of Tuz.  The program considers these to be "spires".  How could this be useful, and what might be confused with a minaret?