The following is a link to a derivation of an ellipsoidal gnomonic via
ECEF that I did 12 years ago:
http://www.hydrometronics.com/downloads/Ellipsoidal%20Gnomonic%20Projection.pdf
Being thoroughly retired now, and having donated my entire technical
library to a university, I’m not in a position to test this ellipsoidal
version against the criteria stated by Charles, namely “The spherical
gnomonic projection has the property that geodesics map to straight
lines”. That may, or may not, be true for this ellipsoidal version. But
does that matter if this “ellipsoidal gnomonic is a direct perspective
from the geocenter through the ellipsoid onto the tangential plane”, the
same method of derivation of the spherical version?
Noel
On 12/28/2022 3:59 PM, Clifford J Mugnier wrote:
The spherical gnomonic projection has the property that geodesics map to
> straight lines.
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