## Monday, October 17, 2011

### Calculate the straight distance between two points of GPS coordinates

If you need to calculate the straight line distance between two points of GPS (Global Positioning System, geographic coordinates), where both coordinates are known, but you have no GPS, no computers with satellite maps or internet, cannot online, no cellular phone or handphone with GPS facility, or other tools to measure the straight distance, then the Excel file The following can help you.

Also there is the conversion of sexagesimal into decimal coordinates, and vice versa.

Measurement system used is the GPS coordinates WGS-84 system

Examples of sexagesimal coordinates of Jakarta:
6 ° 10'31 .37 "S, 106 ° 49'37 .56" E

Examples of decimal coordinates of Jakarta:
-6.182010, 106.821100

In decimal coordinates:
Positive number indicates the location at North of equator for latitude,  and at East of Greenwich for longitude. Negative number indicates the location at the South of equator for latitude, and at West of Greenwich for longitude.

It uses radius of the earth 6,378.14 km, that is earth radius at equator. As the earth is not perfectly round, then the earth radius may be changed slightly according to local conditions.

I often use those formulas in the Excel sheets to measure the straight distance on mining projects, measure land lot area, straight distance between two addresses, etc.