Geodion tools
Geodesic distance and azimuth calculator
Calculate the shortest ellipsoidal path between two geographic positions, including geodesic distance, forward azimuth and reverse azimuth.
Ellipsoidal geodesic calculationCSV/XLSX batch processingLocal browser processing
Position input
Enter decimal degrees. Latitudes are positive north and negative south; longitudes are positive east and negative west.
Coordinates are processed locally in your browser.
Geodesic result
Distance, metres
—Distance, kilometres
—Forward azimuth
—Reverse azimuth
—Ellipsoid
—Azimuths are clockwise from geodetic north and normalised to 0°–360°. “Reverse azimuth” is the initial azimuth at Position 2 back towards Position 1.
Calculation notes
The calculator solves the ellipsoidal inverse problem between the two entered positions, including difficult long-distance and nearly opposite-point cases.
The result is an ellipsoidal surface distance. It is not a projected grid distance, three-dimensional slope distance or datum transformation. Both input positions must refer to the same geodetic datum/reference frame and coordinate epoch where relevant.
Batch processing
Upload a CSV or XLSX file with latitude and longitude columns for both positions.
Recognised headings include lat1, lon1, lat2 and lon2, with common variants such as latitude_1.
Batch results
—| Point ID | Distance (m) | Forward azimuth | Reverse azimuth | Status |
|---|
Shortest path
The result follows the geodesic on the selected ellipsoid, not a planar map distance or spherical great-circle approximation.
Direction at both ends
Forward and reverse azimuths differ because meridians converge and the geodesic changes direction along its path.
Reference-system context
The calculation assumes both coordinates are expressed in the same geodetic datum and reference frame.
Need geodetic support?