I’m working with some radarsat - 2 data, and everything seemed to be good with my snap process until I switched the calibration to output in dBs.
Now, when I bring it into ENVI or arcmap, the image seems warped at the upper left hand corner. Please see attached.
My basic process is:
Radiometric calibration > output in dBs
speckle filter > refined lee
multilook > 4x4
geometric calibration> elipsoid correction> geolocation grid> bilinear interpolation, UTM/WGS84(automatic)> saving as a geotiff.
I’m still new to SNAP and any help would be much appreciated.
Ah okay. So does that mean then there is a tool in snap to perform the same workflow then output to dB in the end? Or should I be doing my radiometric calibration last?
Agreed - and it is at higher lat. The issue that I think is strange is that when not outputting to dB in my radiometric calibration, I dont have such an issue with this datum and projection.
Calibration should be done early and dB-conversion as late as possible. Many spatial operations (for example simple average) give incorrect results if done in dB scale. Ideally the toolbox should check (and autoconvert internally) to and from dB (there are operators for this under Raster/Data Conversion) but I guess it’s possible that some operators do not check for this.
Though I’m having trouble using the operator under raster/data conversion on my post geometric calibration raster. The linear to dB operator is greyed out and I cant seem to make it available regardless of file type.