If your screen's resolution is 1024x768, the width is 1024. The pixels are then numbered
0, 1, 2, ..., 1023
1024, 1024, ..., 2047,
2048, 2049, ...
etc.
Your array just tells you which province each pixel belongs to.
Wow, that would be very efficient.
So I just take a sprite, store it in an array on a per-pixel basis then?