Understanding GPS Coordinates

Some people have a limited understanding of how GPS works. For the average user, it is enough that you turn on your GPS tracking device and it tells you roughly where you are and helps you find directions to get where you want to go. You don’t even fully comprehend, in a world of fancy interfaces, that what you’re seeing on the screen is literally a series of numbers, representing precise coordinates, behind the fancy user interface. Specifically, you’re seeing where two numbers intersect.

Longitude and Latitude

Your location, at any point on the earth, can be represented by pinpointing your latitude and longitude. The longitude refers to vertical lines that dissect the earth from the North to South Poles. Beginning with the Prime Meridian, which is represented as 0 degrees and moving east beginning and one degree and ending at 180 degrees and indicated with the letter E.

Those moving west of the Prime Meridian also begin with one degree and move on until reaching 180 degrees. These are indicated with the letter W.

The latitude, on the other hand, indicates the north/south location. These numbers begin with zero degrees at the Earth’s equator and increase by one degree moving north or south up to 90 degrees in either direction. Each one indicated by an N or S.

Further Identification Tools

Since most locations on planet earth do not fall exactly on the lines of longitude and latitude. There are three methods used to indicate locations more precisely.

1. Degrees, minutes, and seconds (DMS)
2. Degrees and decimal minutes (DMM)
3. Decimal degrees (DD)

Degrees, minutes and seconds work by indicating the longitudinal line divided into 60 minutes with each minute divided further by 60 seconds. When written out, it looks something like this:

5°24’16.2”N 13°20’26.5”E

Meaning the latitude is five degrees, 24 minutes, and 16.2 seconds north while the longitude is 13 degrees, 20 minutes, and 26.5 seconds east.

Decimal minutes divide the space between the lines into minutes and the space between the minutes is expressed with decimal points.

Decimal degrees work by dividing the space between longitude and latitude lines into decimal degrees. In this formulation, lines north of the Equator are expressed with positive numbers while lines south are expressed with negative numbers.

Fortunately, for most of us, GPS tracking takes the math out of discovering our locations on the planet and the routes to take to get from one point to another. It is far less complex when expressed through user-friendly interfaces.

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