[Proj] Conic projection, but centric (gnomonic)

[Lukasz Komsta]

Dear Steve,

> Lukasz, if you are trying to transform from this projection to wgs84 or GPS,
> you will need to add a +towgs84 or +nadgrids component. I think developing a
> nadgrids gridshift file to accompany this would be the best solution, since

Thank you, in my version of cs2cs (and also online calculators), adding
towgs84 would change the result (but increasing error), whereas adding
nadgrids does not change anything at all (it seems that ellps=sphere
forces this behavior).

With regards,

Lukasz