I need to obtain sigma0 (backscatter) from the subset of Sentinel-1 GRDH product.
Could you tell me:
- If I should firstly subset or calculate sigma0 or it does not matter? In my further work I need only sigma0 cropped to the area of my interest.
- how can I create subset? As I can see there’s createSubset method, but I can’t find any usage example. As I can see the second argument should be the “Rectangle” object (how should I initialize this object in Python/snappy?? Will this object use coordinates in WGS84?)
- how can I calculate sigma0? I know that in the SNAP desktop, I can accomplish that through Radar --> Radiometric --> Calibrate, but I can’t find appropriate option in documentation
Obviously I checked examples: