I have two vector maps. The two maps cover the same area but are split up into polygons differently (i.e. if you were to imagine one map placed above the other, the lines defining the polygons would not line up).
Map1 has its polygons colored red where crime is greater than some threshold, else white.
Map2 has its polygons colored red where poverty level is greater than some threshold, else white.
I wish to create a single map with polygons coloured red where either crime or poverty are above their thresholds. As the polygons from each map are different, new polygons would have to be created. I'm using GRASS.
Each file has an attribute table with several columns describing the polygons.
v.overlay with an 'OR' operation looks like a good candidate, but I cant figure out how to specify the correct attribute column to use for the OR merge.