I think you should define a graph in SNAP to process coherence. Then edit the graph XML and change input file to ${input} and output file to ${output} . From the gpt command line you can then pass those variables in with the -P option: gpt graph.xml -Pinput=file.dim -Poutput=coh
If you have a stack of images then uncheck “multi master” to process them all pair wise: Coherence from slaves from many date Back-Geocoding result