#!/usr/bin/env perl

#
# Tim's script to create Google Earth KML/XML format paths from GPS
# co-ordinate data retrieved using gpstrans(1)
#
# Copyright (C) Tim Haynes <pig+gps@sty.nu>
# Licensed under the terms of the GPL:
# http://www.gnu.org/copyleft/gpl.html
#

# Regexp filter as first parameter:
$filter=shift || ".*";

# Default altitude as second parameter:
$alt=shift || 1.5;

print <<EOF;
<?xml version="1.0" encoding="UTF-8"?>
<kml xmlns="http://earth.google.com/kml/2.0">
<Placemark>
<Style>
    <LineStyle>
      <color>ff20ff30</color>
    </LineStyle>
</Style>
<LineString>
<altitudeMode>absolute</altitudeMode>
<coordinates>
EOF

while (<>) {
  chomp;
  next unless /^T/oig;
  next unless /$filter/;
  my @parts=split /[^\d.-]/;
  my $when="$parts[4]-$parts[3]-$parts[2] $parts[5]:$parts[6]:$parts[7]";
  my $lat=(abs($parts[8])+$parts[9]/60+$parts[10]/3600)*sgn($parts[8]);
  my $long=(abs($parts[12])+$parts[13]/60+$parts[14]/3600)*sgn($parts[12]);

  print "$long,$lat,$alt\n"
}

print <<EOF;
</coordinates>
</LineString>
</Placemark>
</kml>
EOF

################

sub sgn {
  my $n=shift;
  return ($n==0)?0 : $n/abs($n);
}