|Finding Your Latitude, Longitude and Elevations|
How you go about finding your latitude and longitude depends to some extent on whether you want to know your 4-digit grid square or your 6-digit grid square. Finding a 6-digit grid square requires considerably more precision in latitude and longitude. The 4-digit grid squares covers a pretty big area, while the 6-digit grid square is fairly small. The actual size of a grid square depends on the particular location, as the 1° of longitude represents different distances at different latitudes; longitude lines are closer together at the Earth's poles than at the equator.
The first step, then, is finding your latitude and longitude as accurately and precisely as you can. There are several common methods for doing so:
For a database of USGS New Mexico Map Products These maps usually include two coordinate systems to define location. One system uses latitude and longitude-- this is what we want. The other system is the universal transverse mercator (UTM) system that consists of squares 1 kilometer on a side. For finding your grid square, use only the latitude and longitude system. See Grid Squar Calculator
To obtain the 7.5-minute map that covers your location, you need to determine the reference code, map name and state. You'll find this information in the map index for your area. Contact USGS for information about pricing and how to order topo maps.
Many outdoor, sporting-goods and camping stores also sell USGS 7.5-minute maps. Check your local Yellow Pages.