For the to quantify differences between layers?  Please help!

Discussion created by gymnastjillx on Oct 13, 2010
Dear GIS Gurus,

If you could help here it would be immensely appreciated.  Attached I have a simple JPG that clearly shows the problem I have.  I basically have two soil layers (one looks like a grid, other shows actual contours) and I need to quantify the difference between the two layers.  

I believe I know how to this quantitatively by area (i.e., how MUCH of each soil type is represented in each layer in each map), but what I really need to do is quantify it SPATIALLY.  In other words, to figure out not just how different the maps are in general, but to show specifically WHERE the differences are between them - likely requiring the production of a third map.   Ideally I'd like to show directionality of differences (e.g., in these areas the soil category went up, in these areas it went down, in these areas the same, etc). 

Does anyone know how to do any of these steps?  Please help!  And thanks so so much!

Jill      24/f/USA