How accurate are topo maps?
The most detailed topo maps (1:24,00 scale) usually show elevation contours in 40 foot intervals. According to US Geological Survey guidelines, CONTOUR LINES PRINTED ON THESE MAPS CAN BE IN ERROR BY 20 FEET. In some cases, topo maps error can be larger than 20 feet. The biggest problem with using topo maps to try to get exact elevations is that it is difficult to precisely locate oneself on a topo map. Anyone who is experienced in using topo maps knows that you can gauge your location on the map.
