I have a DTM with 40cm resolution and a DSM with 2cm. Now I would like to compare the two so I can identify vegetation that is higher than a certain distance from the ground. I changed the pixel size from the DSM to 40 cm and wanted to use the raster calculator with a the simple calculation: Output = DSM - DTM I get the message "insufficient memory available for this operation" I have 16gb of ram and would consider my laptop as good. Even after splitting up the area, it would not calculate the difference.
What can be the issue? Is my equation correct?