How to interpret the height of output DSM.tif? about s2p HOT 5 CLOSED

I think I found the answer of part of my question. According to this article, <HEIGHT_SCALE>75</HEIGHT_SCALE> <HEIGHT_OFF>125</HEIGHT_OFF> means that the ellipsoid height is varied from -50 to 200 meters. So s2p uses these two value to calculate the DSM. Therefore, the height in DSM.tif is ellipsoid height. However, I still don't understand why the height in DSM.tif varies a lot than the height of downloaded SRTM elevation model. Can someone give me some insights about this? Or what parameters I can try to make the height difference between DSM.tif and DEM smaller? E.g. using orthorectified image or something like that?

Thank you.

from s2p.

Hi,
I would check the datum (reference surface) for your SRTM (ellipsoid or geoid).
This is because usually RPC's produce heights with respect to the ellipsoid,
but srtm is usually wrt the geoid.
best

from s2p.

Thank you @gfacciol . Do you need further information from me to do that?

Best Regards,

from s2p.

Hi @gfacciol
I found the following information.
DSM.tif: EPSG:32632 - WGS 84 / UTM zone 32N - Projected
SRTM DEM: EPSG:4326 - WGS 84 - Geographic

Best Regards,

from s2p.

This issue is closed because I found the answer. The SRTM is in geoid.

from s2p.