Hi,
This sounds like a pretty simple algorithm to code, are the arrays of different lengths or similar lengths?
You can locate the maximum in an array using the max function, which will also give you its location in the array if required.
If you are plotting something on an (x,y) place you need two dimensions so do you want to plot (maxarray1, maxarray2) this is the only part I'm unclear on.
Let me know if you want to proceed!
Jamie