Hacking Google Maps and Google Earth (ExtremeTech)

Chapter 10: Overlaying Statistical Data

#!/usr/bin/perl -w

use strict;

open(DATA,$ARGV[0]) or die “Couldn’t open file; did you forget it?”;

my $counter = 0;

print “”;

my @popyears;

while()
{
next unless (m/[a-z]/i);
$_ =~ s/\”//g;
$counter++;
if ($counter == 1)
{
my ($city,$lat,$lng);
($city,$lat,$lng,@popyears) = split /\t/;
$counter++;
next;
}
chomp;

my ($city,$lat,$lng,@pop) = split /\t/;

printf(‘<city title=”%s” lat=”%f” lng=”%f”>’,$city,$lat,$lng);

print(“\n”);

for(my $i=0;$i < scalar(@pop);$i++)

{

$pop[$i] =~ s/,//g;

next unless (defined($pop[$i]));

printf(‘<pop year=”%s” value=”%d”></pop>’,$popyears[$i],$pop[$i]);

print(“\n”);

}

print(“\n”);
}
close(DATA);

print “”;

The script is comparatively straightforward. The data is extracted and a little cleaning up is
performed (you remove double quotes from all lines and commas from population numbers)
before generating a suitable XML file. Following is a sample of the generated file: