Add thiessen polygons as rasters

Discussion created by vickyginn on Feb 9, 2011
Hi, any help greatly received. I have three layers of different thiessen polygons which I want to add together in order to compare the represented territories. I thought that if I gave each layer a value I could sum these and that would produce a raster with high values for where there were lots of thiessen polygons and low values where there isn't.
I've tried converting them to rasters and adding them together which seemed to make only limited sense.
Also tried converting to rasters and using mosaic to create a new raster but that didn't make much sense at all.
Is there a (better) way to do this?
Many thanks,