I am looking for a way to antialias integer DEM data (hgt file) to float GeoTIFF. That way I want to avoid
gdaldem hillshade artefact lines which you can see in this picture:
I don't want to blur DEM data to keep the result sharp. I am actually looking for a tool to interpolate pixels in the following (or better) way. For simplicity the illustration uses only 1D, not 2D:
Edit: Adding image for elevation changing its direction. Input is blue (pen), output is dashed gray (pencil):
I bet that somebody has already invented such algorithm ;-). I am "only" looking for a tool that implements it.
Regarding 2D, algorithm would be applied in both directions and result would be average of it.