>>Use an anonymous array as value:

>>$coordinates{$zone} = $a1, $a2, $b1, $b2 ;

>>Don't forget to dereference it when you read your coordinates back out:
>>($a1, $a2, $b1, $b2) = @{$coordinates{$zone}}
This only allows one coord per zone, does it not? Is there a way of pushing the coordinates into $coordinates{$zone}?
I supply a coordinate and I get a zone in return, there are many different zone types returned. I'd like to be in a position to plot out on a bitmap where each zone is located. To do this, I'll need to store the coordinates for each zone.