modify A2M read to use variable divisor
modify A2M read to use variable divisor

see upstream changes to a2m RASTER format
akrherz/dep,akrherz/idep,akrherz/idep,akrherz/idep,akrherz/dep,akrherz/dep,akrherz/idep,akrherz/idep,akrherz/dep,akrherz/idep,akrherz/dep