Coordinates

Coordinates are a means of numerical description for a location on the earths' surface. Geocaching uses coordinates of Latitude and Longitude (Lat/Lon) to describe the location of the cache or its' intermediate waypoints.

For the purposes of geocaching, Lat/Lon coordinates are expressed in Degrees, Minutes, decimal minutes ( DDD°MM.mmm' ), but for purposes of general navigation (especially at sea) Lat/Lon is expressed in Degrees, Minutes and Seconds ( DDD°MM'SS" ).

An alternate system of coordinates is UTM, which is short for Universal Transverse Mercator. UTM would be a better system to use for geocaching, because it's more accurate. Being based on the metric system it's well suited to terrestial applications, unlike DDD°MM.mmm'. However, that point seems to have been overlooked at the time geocaching was invented, so we are stuck with DDD°MM.mmm', unless you want to convert from DDD°MM.mmm' to UTM and back again.