# NAME
Geo::Coordinates::GMap - Routines for converting decimal lat/lon to Google
Map tiles, and back again.
# SYNOPSIS
use Geo::Coordinates::GMap;
my ($tile_x, $tile_y) = coord_to_gmap_tile( $lat, $lon, $zoom );
my ($new_tile_x, $new_tile_y) = zoom_gmap_tile( $tile_x, $tile_y, $old_zoom, $new_zoom );
my ($x, $y) = gmap_tile_xy( $tile_x, $tile_y, $scale );
# DESCRIPTION
While working on the mapping tools on toxicrisk.com I came to the conclusion
that we were dealing with too much data to make everything a GMarker, even
when using the marker manager.
So, I needed to generate static map tile images. But, to do this, I needed a
way to convert my decimal lat/lon points in to tile numbers, and the pixel
values on those tiles.
This module makes this process simple and accurate.
# FUNCTIONS
## coord\_to\_gmap\_tile
my ($tile_x, $tile_y) = coord_to_gmap_tile( $lat, $lon, $zoom );
Given a decimal latitude and longitude, and a Google Maps zoom level (0 being farthest away
and 20 being the closest that I'm aware of that you can get), this function will return the
GMap tile location as a fractional x and y coordinate.
## zoom\_gmap\_tile
my ($new_tile_x, $new_tile_y) = zoom_gmap_tile( $tile_x, $tile_y, $old_zoom, $new_zoom );
Converts fractional tile coordinates, as created by coord\_to\_gmap\_tile(), from one
zoom level to another.
## gmap\_tile\_xy
my ($x, $y) = gmap_tile_xy( $tile_x, $tile_y, $scale );
Given a tile's x and y coordinate as provided by coord\_to\_gmap\_tile(), this function
will return the pixel location within the tile.
The `$scale` argument may be supplied which can be used to produce high-res tiles.
At this time Google states that the scale can be `1`, `2`, or `4` (only Google
Maps API for Work customers can use `4` with the Google Maps API). If not specified
the scale will default to `1`.
# TODO
- Implement a routine to convert tile coordinates back in to lat/lon decimal
coordinates.
# AUTHOR
Aran Clary Deltac <
[email protected]>
# LICENSE
This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.
