Digital data is provided for the indexes of:- 1:100,000 scale topographic maps- 1:250,000 scale topographic maps- 1:1,000,000 scale General Reference mapsThese indexes are those used in the online map
Most USGS topographic maps use brown contours to show the shape and elevation of the terrain. Contour intervals vary, depending mainly on the type of terrain and the scale of the map. (Scale is the re
