Hi,
I am wondering how to re-produce in GRASS 6.4.2 the following data processing step which I have gotten in some sort of ArcGIS notation:
Population_exposed = zonalstatistics( layer1, “value”, layer2 * layer3, sum, # )
layer1 and layer2 are CELL, layer3 is FCELL
r.statistics doesn't seem to like floating point values, so do I really have to do the below steps in analogy to exercise [1], i.e. (untested):
# Create a scaled integer temp map, something like:
r.mapcalc 'temp_map = round(layer2 * layer3 * 10000)'
# Sum up per region
r.statistics base=layer1 cover=temp_map out=sum_map method=sum
# Create output in tabular format
r.stats --quiet -c layer1,sum_map | awk '{print $1, $3 / 10000}' > Population_exposed
I feel that I am overlooking something which would be simpler.
Hermann