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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.

Distance Units: nmkmsm Earth model: Spherical (1'=1nm)WGS84/NAD83/GRS80Clarke (1866)/NAD27InternationalKrasovskyBessel (1841)WGS72WGS66User defined

Compute lat/lon given radial and distance from a known point

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.

Distance Units: nmkmsm Earth model: Spherical (1'=1nm)WGS84/NAD83/GRS80Clarke (1866)/NAD27InternationalKrasovskyBessel (1841)WGS72WGS66User defined

Spheroid

Enter "user defined" spheroid parameters here:

History

7/13/98 Removed a line of debugging code, giving irritating Javascript alerts, left over from the 5/16/98 changes

5/16/98 Changed the great circle radial and distance algorithm to one valid for unlimited distances. Previous was only valid for ranges up to one quarter of the earth's circumference in longitude. Note that the Vicenty algorithm for (ellipsoidal) course and distance may fail to converge correctly, or at all, if the final point is within 37' of arc of the antipodes of the first point.

5/12/98 Eccentricity of NAD27 (Clarke1866) ellipsoid obtained from my reference "Coordinate Systems and Map Projections" by D. H. Maling was in error. 1/f changed from 298.97866982 to 294.9786982138

11/9/97 Fixed bug where if the output lat/lon was DD 6.MMMM (ie 6 minutes), the result was incorrectly rounded up to the next degree.

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