Global Positioning System (GPS)

The distances vary. A degree, minute or second of latitude remains fairly constant from the equator to the poles; however a degree, minute, or second of longitude can vary greatly as one approaches the poles (because of the convergence of the meridians...
We generally emphasize the following four points:a) Select a coordinate system (also called a "position format") you feel comfortable using. We suggest using Universal Transverse Mercator (UTM) or latitude/longitude. Most users find UTM coordinates ...
The USGS publishes approximately 57,000 different topographic maps covering the United States. Topographic maps show contour lines (elevation and landforms), hydrography (rivers, lakes, marshes), transportation (roads, trails, railroads, airports),...