# 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 # 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.