Sentinel-1 SAR Calibration is different when different extent of extractroi
Description
on data S1B_IW_GRDH_1SDV_20170114T231224_20170114T231249_003851_006A05_5E04, like S1Tiling lib, I process data over S2 tiles. For that purpose, to speed up processing I "clip" the raw S1 data using extractroi (fit mode of a shape file in epsg 4326) and then apply calibration (test using default settings) and finish by orthorectification.
When I overlay comon area of the same data I discover that there is not same backscattering value as shown in the screenshot(exactly same qgis style to illustrate the shift in the backscatering values).
I have same effect in other areas.
[Update] :
- I have tested using 2021 data (always downloaded from ASF) and I have the same issue.
- I have updated my processing chain to first calibrate the full scene and then use ExtractRoi and the problem is gone between 2 S2tile East/West. Now I am testing the processing over the full study area.
Configuration information
Windows 7 or ubuntu 18.04 OTB 7.2