ok so here is what I did in the end:
I made three matrices (x,y,z1 x,y,z2 x,y,z3) x=1:10 and y=1:10 then I subtracted the matrices from one another z1-z2 and z1-z3, then I cut and pasted the two resulting matrices into excel. In excel I made a third matrix out of the first two. For the third matrix: any cell that had a negative value on either of the first two matrices was copied as a 0 onto the third. then I copied the lowest value between the first two matrices in each cell into the corresponding cell in the third matrix. I placed this resulting matrix back into matlab and made an image, setting the color map to black at zero and light green to dark green for the rest. I did the same thing two more times (z2-z1,z2-z3 and z3-z1,z3-z2) and colored the other two images the same way but with a different color (i.e. blue instead of green).
so now I have 3 images, I just have to make a composite of this by removing all the black cells and laying what's left on top of each other. viola, now I have a map of what item is most prominent at each location and to what degree.
I don't know if I described it very well but it was easy and didn't take long. I'm putting this up in case someone else runs into a similar problem.