Convert DMS and decimal degree coordinates for field use
A coordinate can be correct but interpreted in the wrong format. DMS versus decimal degrees is a common field mistake.
Field takeaways
- DMS uses degrees, minutes and seconds.
- Decimal degrees use one number for latitude and longitude.
- Comma, decimal separator and direction letters can cause errors.
- KML and map sharing commonly use WGS84 lat lon.
- MapLab Survey helps keep coordinate format context.
The usual confusion
Reading 41°30' as 41.30 degrees is an error of almost a kilometre. Thirty minutes is half a degree, so the correct value is 41.5. This single conversion is where field positions are lost most often.
Signs and letters
N and E are positive, S and W negative. A lost sign flips the hemisphere and puts the point on another continent.
Keep the decimals
Every decimal place you drop moves the point on the ground. Copy the full value, especially if you intend to navigate to it.
Check before you commit
After any conversion, display the point on a map and confirm it falls in the expected area. That visual check takes seconds and catches sign and order errors a table of numbers never reveals.
Try these steps on your own phone.
MapLab Survey handles RTK/GNSS point capture, drawing, area and volume calculations and coordinate conversion, then exports to DXF, KML/KMZ, GeoJSON, Shapefile, GeoPackage, NCZ or CSV. Capture, calculation and export work offline. Live NTRIP corrections and online basemaps need a connection.
Frequently asked questions
What is DMS?
Degrees, minutes and seconds coordinate format.
What are decimal degrees?
Latitude and longitude as decimal numbers.
Why does a point go to the wrong place?
Format, order, datum or decimal separator may be wrong.
What does KML use?
Commonly WGS84 latitude and longitude.
Technical references
The field guidance in this article is aligned with the technical and official references below.
Related: Lat lon to UTM · Google Maps coordinates · Coordinate conversion app · MapLab Survey