I've written some code which calculates how far an animal is from a set location. I want to be able to return the number of animals who are within a certain distance (10km) from the set location. Im using a data file with 300+ animals sorted into Name - Latitude - Longitude. I thought I would create a counter for this, which would increment by 1 when the program found an animal which was within the 10km, but I'm not having any luck with that. (E.g. along the lines of "if $Dist < 10, ++counter" Here's my code so far: 
$Mam = 'Mammal.txt';
open(FILE, $Mam) or die "Error. Could not open '$Mam'.";
while(<FILE>)
{
chomp;
@Loc = split(/\t/, $_);

my $Dist;
$Dist = CalculateDistance(54.988056, -1.619444, $Loc[1], $Loc[2]);

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The formatting is terrible at the moment since I'm just playing with it. I havn't included the CalculateDistance subroutine as it is quite long, but I can if it will help. I tried 
while($Dist < 10)
{ 
$counter++;
    print "$counter animals are found withing 10KM\n"
  }

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but just get the number 0 repeated. The code should be displaying one number which represents the total number of animals found within 10KM of the coordinates provided. I can't see where I'm going wrong.

In reply to (Beginner) Return number of variables within a set distance. by Halbird

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