[GRASS5] [bug #3630] (grass) error in v.proj/r.proj in gnomonic projection

[Morten Hulden]

Paul Kelly via RT wrote:
> According to the output of the "proj -lP" command:
> gnom : Gnomonic
>         Azi, Sph.
> gnomonic projection can only be used with a spherical earth model. So you 
> are going to get undefined behaviour / errors if re-projecting between an 
> ellipsoid and a sphere.

I wonder if a two-step reprojection temporarily could solve this: first 
projecting from a location with krassovsky ellipsoid into a lonlat 
sphere location, then to gnomonic. Of course for rasters resampling 
errors would be greater but keeping resolutions at similar values could 
perhaps retain acceptable quality.

Morten