GPS COORDINATES

Most of us never need to use numerical GPS coordinates to take advantage of the many location-based services that are available to us. We simply input an address, or click through from an Internet search, or automatically geotag photos, and our electronic devices take care of the rest. But dedicated outdoors-people, geocachers, pilots, sailors, and more do often need to use and understand numerical GPS coordinates. And some of us technophiles are interested in the workings of the GPS systems just out of curiosity. Here then is your guide to GPS coordinates.

The global GPS system actually doesn't have a coordinates system of its own. It uses "geographic coordinates" systems that already existed before GPS, including: Latitude and Longitude

GPS coordinates are most commonly expressed as latitude and longitude. This system divides the earth into latitude lines, which indicate how far north or south of the equator a location is, and longitude lines, which indicate how far east or west of the prime meridian a location is.

The example of reading the Latitute and Longitude is shown above:

1. In this system, the equator is at 0 degrees latitude, with the poles being at 90 degrees north and south. The prime meridian is at 0 degrees longitude, extending east and west. 
2.  Under this system, an exact location on the earth's surface can be expressed as a set of numbers. The latitude and longitude of the Empire State Building, for example is expressed as N40° 44.9064', W073° 59.0735'. The location may also be expressed in a numbers-only format, per: 40.748440, -73.984559. 
3. With the first number indicating latitude, and the second number representing longitude (the minus sign indicates "west"). Being numeric-only, the second means of notation is the most commonly used for inputting positions into GPS devices.