# Perl script to convert Google maps tiles to the DSmaps naming convention
# 

use File::Copy ;
use File::Path ;

# open our gtiles directory, read the files in there into an array
# and chop off the first two entries (. and ..)

opendir(gtiles, gtiles) or die "can't open dir: $!" ;
@files = readdir(gtiles) ;
shift(@files) ;
shift(@files) ;

# for each file, figure out the name in the DSmaps format and copy to that

for $g (@files) {

$file = $g ;
$filename = $file ;
substr($filename, -4, 4) = "" ;  # chop the extension off the end of the file so we just have the qrst data

%qrst = ( "q" => '00', "r" => '10', "s" => '11', "t" => '01'); # coords for each letter

@filesplit = split(//, substr($filename, 1)) ; # split it up into individual letters, ignoring the first one

# calculate the X, Y, and Zoom values from the qrst values

$x = 0 ;
$y = 0 ;
$z = 17 ;

for $i (@filesplit) {
	$x = $x * 2 + substr($qrst{"$i"}, 0, 1) ;
	$y = $y * 2 + substr($qrst{"$i"}, 1, 1) ;
	$z = $z - 1 ;
}

# convert to hex for DSmaps
$zoomdec = $z ;
$x = sprintf("%X", $x) ;
$y = sprintf("%X", $y) ;
$z = sprintf("%02X", $z) ;
$xx = "000" ;
$yy = "000" ;
while (length($x) > 2) {
	$xx = $xx . substr($x, 0, 1) ;
	substr($x, 0, 1) = "" ;
	substr($xx, 0, 1) = "" ;
}
while (length($y) > 2) {
	$yy = $yy . substr($y, 0, 1) ;
	substr($y, 0, 1) = "" ;
	substr($yy, 0, 1) = "" ;
}
if (substr($x, 0, 1) eq 0) {
  if (length($x) > 1 ) {	
substr($x, 0, 1) = "" ;
}}
if (substr($y, 0, 1) eq 0) {
  if (length($y) > 1) {
	substr($y, 0, 1) = "" ;
}}
# create the directory and file from what we just figured out

mkpath(["$x\\$y"]);
$destfile = "$x\\$y\\$xx$yy$z.GMT" ;
$startfile = "gtiles\\$file" ;
print "$startfile, $destfile \n" ;
copy($startfile, $destfile) or die "well that didn't work:$!";
}
closedir(gtiles);