geoid height correction is missing

[think-nice-things]

As far as I can see height data is systematically wrong. In my location I get heights which are about 40 m too high for example but as the geoid is different on each point of the earth it might be a totally different offset at your location.

This is probably due to the fact that geoid correction is missing. See for example this thread: https://github.com/Akaflieg-Freiburg/enroute/issues/28

A simple example to do pretty good geoid correction is at geoid.py which uses the EGM96 gridded data WW15MGH.DAC and interpolates with splines. Btw. this file and method is for example also used for the geoid correction osmand.