Hi,
If I got you correctly , you might consider somthing like this.
let say you read the zones and coordinates from file of similar
structure:
#Zone #coordinates
aaa 1.5 2.3 77 51
bbb 2 -9 3 12
my %coord = ();
while(<IN>){
my @temp = split(/\s+/);
$coord{$temp[0]) = join(':',$temp[0],$temp1 ... );
}

Now you have your list in one pass , and you can search
your hash in single entry.
for example:
if(defined($coord{'aaa'}{
print_co($coord{'aaa'});
. . .
}
I hope it is good for you
michaelg