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USGS Maps
If you go to the United States Geological Survey website you can download maps of areas of the United States. These maps include current versions and older historical maps. They come in different sizes covering large and small areas. The maps that cover a small area have greater detail, contour intervals of five or ten feet versus five or ten meters in other maps covering a larger area. You can download pdf versions of these maps. Here are a couple of small samples. ( http://geonames.usgs.gov/pls/topomap...amden%5C%2CAll )
The first map is a 1936 7.5 minute E/W by 7.5 minute N/S of Camden, Tennessee close to the Tennessee River that seperates the West Tennessee division from Middle Tennessee division. (It would take sixty-four maps of similar area to cover one degree of latitude by one degree of longitude.) The second map is a 1985 7.5 minute E/W by 7.5 minute N/S of Camden, Tennessee. Notice how much bigger the Tennessee River is after TVA and the Corps of Engineers built the dams. With the increased use of tablet computers one could download a series of modern maps for the PC's to have on their NavCom and then a series from the 1930's on another tablet for the PD to have. As pdf's using the snapshot feature one could take a snapshot of an portion and paste it into a drawing or similar program to add some PD notations. |
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