The best place to get topo maps is your local geological survey. Your
state geological survey or the USGS-United States Geological Survey.
Also, you might want to look into Land Sat. Imagery and radar imagery.
These types of maps are used for remote sensing and have wonderful
colors and patterns. They are little harder to get a hold of, but you
might try the geology or geography department at your local
university. Check out a remote sensing book from the library, it will
give you an idea of the types of maps that are available. Differences
in vegetation and geology show up as different colors and patterns.
They are really interesting.Good Luck!
 
Pauline Denham
University of Nebraska State Museum
Technical Artist