Overlap of two polygon layers

Discussion created by jadoty on Sep 2, 2011
Latest reply on Sep 8, 2011 by csny490
I have a buffer of an original line shapefile, now a polygon file, and want determine what percentage that buffer occupies in polygons from another poly shapefile.  I thought either intersect or union was the way to go, but I can't seem to get the numbers to work out.  I know the total area of the buffer by running statistics on the field.  And I have calculated geometry on the output files, The problem is that the area of the union/intersect polys are much higher than the original buffer area.  Perhaps in the union I am inadvertently including both sets of polygons in the calculation?  But in the intersect, I don't understand why the total area of the original buffer is much lower than the intersect output.  Any suggestions?  Am I at least on the right track on the procedure, should both of these overlays work or just one or the other?