Geomorphology

Digital elevation model analysis with Microdem

This lab is meant to give you the chance to learn how to do some rudimentary work with the program Microdem to manipulate DEMS and other geographic data.

Microdem

Microdem is an excellent free program written by Professor Peter L. Guth of the US Naval Academy.
http://www.nadn.navy.mil/Users/oceano/pguth/website/microdemdown.htm

Geographic data

DEMS: I found a nice site for Arizona here: http://geogdata.csun.edu/az_index.html

Digital Orthophoto Quarter Quads: http://aria.arizona.edu/

Exercises

Mt. St. Helens

DEM examination, profiles and contours.

Open the files oldmtsthelens.dem and newmtsthelens.dem (File->Open DEM)
Use the zoom tools to examine the DEM.
Use the LOS tool to calculate line of sight profiles (LOS icon; doubleclick at the beginning and end of the profile). Create an east west profile for both DEMs. How much elevation was lost?
Calculate contours (use a 1000 m contour interval; Overlay->Contour)

Black Canyon City

DEM merge and perspective views.

File->Data manipulation. Click on Merge->DEMs and select sequentially these files: BCC30.2.1.1218292.tar and SQM30.2.1.1218229.tar. Click cancel. Save the new merged file on your desktop with a meaningful name.
Close and then open the new dem (File->Open DEM)
Find the Black Canyon City landslide (zoom in).
View->OpenGL (assuming OpenGL capability on machines
View->Perspective. Double click at viewpoint and then sweep out viewshed. Modify parameters if necessary.
View->Flythrough. DOubleclick points along flightpath. Right click when done selecting path and then play it. Modify parameters as necessary.

Tempe quadrangle

Image overlay

File->Open DEM. Choose tempe30.2.2.975455.tar.
Explore. What are the hills?
File->Open image. Choose CUTTEMPE.IDX. This is a piece of the DOQQ of Tempe. I cut it out of the big image using the File->Data Manipulation tools->Subset imagery and then graphically defined it. Don't try now because it may be a bit slow.
Explore Image. Note how cursor highlights location in both images
Modify->Set DEM with image.
Make a perspective view looking at Tempe Butte on the image. Also try oblique and flythroughs.

Geomorphology