GPS Latitude and Longitude Distance Calculator
This converter and calculator requires the use of Javascript enabled and capable browsers. It is designed to convert the two different and distinct methods of coordinate nomenclature from one methodology to the other, and to calculate the distance between two sets of coordinates. Due to the fact that GPS information is so readily available now for daily weather information, automotive use, aviation, marine and personal use, many companies have set their own standards as to how that information is displayed and disseminated. (Get NAD27 and NAD83 conversion info from NOAA here...) Either method is very accurate in the native form but converting between them can create substantial error. When using a hand held GPS for instance, you may have to use the information and convert it to or from what a GIS map displays. We have created this converter and calculator to take decimal degrees or degrees and decimal minutes, and convert to the other. In order to establish a point, you MUST have latitude and longitude coordinates in one form or the other. You must enter both points to get a distance calculation. If you need to get that information to a degrees, minutes and seconds format, use the GPS Converter. The distance calculations and bearing are based on a true spherical model. The different latitude and longitude formats are as follows:
Degrees, minutes and seconds (DDD, MM, SS) is the conventional method of presentation. (Latitude is DD while longitude is DDD.) There is usually a quadrasphere designation as well, such as N, S, E or W, based on the equator and the prime meridian. For the hemisphere, either North or South, the designation is N or S for latitude. East of the prime meridian is E (positive) and West of the prime meridian is W (negative). Negative numbers (in certain situations, Southern latitude is displayed as negative; if you see a negative latitude, it is South while a negative longitude is West) can also be used to express a quadrasphere designation. In this converter, we do neither since it does not matter. All numbers are assumed to be positive as far as entry and are actually determined by the N, S, E or W entry.
Decimal Degrees is displayed as the degrees in normal value, with both minutes and seconds in decimal format, as a degree value. There is ONLY a degree designation. (DDD.DDDD) A maximum of 4 decimal places is adequate.
What is most often known as GPS format (though not all GPS units use it or agree on it...), is displayed as (DDD,MM.MMMM) in which seconds are converted to decimal minutes, as a minute value. Seconds have the value of 0 to 60, with 0 and 60 (usually designated as 0 to 59 and then restarting at 0) being the same value, minutes have the same characteristics and degrees are valid from 0 to 180 and 180 to 0, (0 and 180 do NOT have the same value) both North and South of the equator, and East and West of the prime meridian. Now that the designations (and reasons for them) are perfectly clear, here is the set of formulae if you need to do this manually.
Degrees Minutes Seconds to Degrees Minutes.m (GPS)
Degrees = Degrees, Minutes.m = Minutes + (Seconds / 60)
Degrees Minutes.m to Decimal Degrees
.d = M.m / 60, Decimal Degrees = Degrees + .d
There are 60 minutes in a degree and 60 seconds in a minute (3600 seconds in a degree), both seconds and minutes are segments of ARC and not time. There are 360 degrees in a complete circle or sphere but in all longitude measurements, the total of the degrees is expressed as 2 halves of 180 degrees each, moving East and West from the prime meridian. East is positive and West is negative. Latitude is designated as North and South but in 90 degree sectors. North is positive and South is Negative. It is possible to have a 3 digit degree designation for longitude but only a 2 digit designation for latitude.

