I have recently implemented the computation of the projected local incidence angle based on a DEM and an orbit file in Python. I mainly followed the Java implementation in SNAP. The outcome looks good, but a pixel shift (southeast <-> northwest) seems to be present (using the same external DEM and gravity model). I have checked my code often, but I can’t find any issue, which could cause this problem. The computation can be compared with computing a hillshade, therefore I applied a hillshading on the DEM using QGIS. Surprisingly, the outcome of the Python package fits very well with the hillshade, but not with the one from SNAP. Is this comparison via a hillshade even allowed? Is there any possibility to debug the Java code of SNAP to see at which point both depart?
Please download and compare the images below:
Any advice/help would be very welcome.
Thank you in advance!
PS: I am using SNAP 6.0. Please let me know if you need further information or data files.