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Great Circle Calculator

Compute true course and distance between points.

Enter lat/lon of points, select distance units and earth model and click "compute". Lat/lons may be entered in DD.DD, DD:MM.MM or DD:MM:SS.SS formats.

Note that if either point is very close to a pole, the course may be inaccurate, because of its extreme sensitivity to position and inevitable rounding error.

Lat1
Lon1
Input Data
Lat2
Lon2

Course 1-2
Course 2-1
Distance
Output

Distance Units: Earth model:

Great Circle Dead Reckoning

Enter lat/lon of initial point, true course and distance. Select distance units and earth model and click "compute". Lat/lons may be entered in DD.DD, DD:MM.MM or DD:MM:SS.SS formats.

Note that the starting point cannot be a pole.

Lat1
Lon1
Course 1-2
Distance 1-2
Input data

Lat2
Lon2
Output

Distance Units: Earth model:

Spheroid

Enter "user defined" spheroid parameters here:

Major radius a (km): Inverse flattening 1/f:

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