Now I get it!

Thanks folks for helping me see the options here. Since the number of feet between 0 and 30,000 would require me to store 30,000 locations, this does not seem feasable on a PIC.

I now understand how it would work however, and options might be to store 3000 locations and increment every 10, etc. However, for this application I think I will chalk it up to 'not in scope'..

Thanks,

Tom