The Gnomic projection is used for plotting great circle arcs as straight lines on a map. Scale, shape and area are badly distorted along these paths, but the great circle routes are precise in relation to the sphere.
The "Gnomic" Projection has the following Parameters:
| Parameter Name | Parameter String | Units | 
| Longitude of the Center of the Projection | central_meridian | |
| Latitude of the Origin of the Projection | latitude_of_origin | |
| Radius of the Sphere | spherical_radius | |
| False Easting | false_easting | |
| False Northing | false_northing | 
Note: If the spherical_radius parameter is set to a value greater than zero, then it will be used as the radius of the sphere. If this parameter is set to a value less than or equal to zero, then the SemiMajor radius of the Ellipsoid will be used as the radius of the sphere.