irregular image map
 

appreciate any help.
I'm try to create an image map that looks like a target(concentric circles)
which has been split into 8 slices and has 3 rings. When i click on a segment
of a ring, i want the segment to change colour and to run some code. I also
want to be able to fill a cell with some text when the mouse is over a
segment.

The problem i have is that the segments aren't rectangular so there is
overlap. I've tried everything i can think of.