Work with curved height maps?

[okla]

Am I right that this only works with "flat" height maps: F(x, y) = z where x, y, z are cartesian coordinates? For example, there is SRTM DEM set where each tile represents a part of Earth surface, so it's curved: F(f, l) = h where f and l are latitude and longitude (angles). Is there any way this can be used for such height maps?

[fogleman]

Correct, this is cartesian only.

I have a different project (below) that can do an entire planet, but nothing that does ellipsoid tiles.

https://github.com/fogleman/demsphere

[okla]

I see. I am interested in the optimization algorithm only, by the way. Wonder if it can be used for curved height maps somehow.

[mdsumner]

I don't see why it matters fwiw, the gradient is not "correct" but surely it works as well for thinning spurious detail ?? and any tile in longlat is likely a small enough region to be locally close enough? Beyond that you should use a projection, but then you have to remodel the data and that's better done as a mesh often. 🙏