Thank you. I have snap 8.0. But I have already came to conclusion, that the code is OK.
The problem is with that tif file. I have created it with gdal module in Python. In ArcMap it has correct values, but in Snap it is all zeros. I guess I am missing something in that raster creation process, but have no clue what. Don’t you have some tip what may be the problem?
I found it. I have created output raster for writing tif in python like this: out_ds = driver.Create(out_file, cols, rows, 1, gdal.CGDT_Float32)
The issue was that it was complex number not floating point. This way it worked: out_ds = driver.Create(out_file, cols, rows, 1, gdal.GDT_Float32)