S1 VH contains only NaN values after Radiometric Terrain Flattening

s1tbx
#1

I’m working with Sentinel-1 IW GRDH data. For pre-processing I have a processing chain consisting of “Apply Orbit File”, “Calibrate”, “Radiometric Terrain Flattening” and “Range-Doppler Terrain Correction”.

Since the last update of SNAP, there seems to be a problem with the Radiometric Terrain Flattening module. The VH polarization looks fine until it is entered into the Radiometric Terrain Flattering module. In the resulting data set, the VH polarization contains only NaN values.

The VV polarization is not affected by this.

Therefore, I assume a bug in the Radiometric Terrain Flattening module, which is quite annoying, as it was working fine so far.

I hope that this will be corrected as fast as possible as we want to use SNAP for a SAR Summer School.

Technical info:

I’m using the latest version of SNAP (with all the updates installed) on Windows 10 and on Linux (Ubuntu 18.04 LTS) and tried to process these scenes:

S1A_IW_GRDH_1SDV_20200720T170004_20200720T170029_033541_03E2F9_AF56.zip
S1B_IW_GRDH_1SDV_20190801T165914_20190801T165939_017395_020B63_47D3.zip
S1B_IW_GRDH_1SDV_20200804T052522_20200804T052547_022769_02B36C_7C3C.zip

The reported issue occurs under Windows and Linux.

Thanks a lot and best regards…

#2

See Terrain flattening outputs empty VH channel

1 Like
#3

Thanks for the hint. It works.

But it’s still annoying: This module was working fine before! Why has this been changed? It does affect a lot of saved work flows. Hope that it will be brought back to “normal” as soon as possible.