topographic (topo) map– A map that displays contour lines, marked at intervals in feet, to show the elevation and relief of ridges and valleys.
Land managing agencies, wildland fire organizations, emergency services, and search and rescue groups use topographic (topo) maps to the exclusion of all others.
Make sure your topographic map is a recent edition that displays the trail you’re hiking on. Multiple maps may be necessary to cover the full route of an extended trip.
A compass is used to find direction of travel and establish (in conjunction with a map) current location. Carry a compass with a clear base, hinged sighting mirror, and adjustable declination.
Global Positioning System (GPS)
A GPS unit supplements, rather than replaces the map and compass. In addition to direction of travel and current location, a GPS indicates elevation.
GPS elevation can help establish a position when compared with a topographic map’s contour line elevation.
A map, compass, and GPS are used together for route planning.