NAME
Image::WorldMap - Create graphical world maps of data
SYNOPSIS
my $map = Image::WorldMap->new("earth-small.png", "maian/8");
$map->add(4.91, 52.35, "Amsterdam.pm");
$map->add(-2.355399, 51.3828, "Bath.pm");
$map->add(-0.093999, 51.3627, "Croydon.pm");
$map->draw("test.png");
DESCRIPTION
This module helps create graphical world maps of data, such as the Perl
a number of label locations (longitude/latitude) and outputs an image.
It can attach text to the labels, and tries to make sure that labels do
not overlap.
It is intended to be used to create images of information such as "where
are all the Perl Monger groups?", "where in the world are all the CPAN
mirrors?" and so on.
This module comes with a low-resolution image of the world. Additional
larger images have not been bundled with the module due to their size,
METHODS
new
The constructor. It takes two mandatory arguments, the filename of the
image of the earth used for the background, and whether or not to
display labels.
The label option is actually a font size and name. You must have a local
truetype font in your directory. The font name format is
"font_name/size". For example. If there is a font file called cinema.ttf
somewhere in the font path you might use "cinema/20" to load a 20 pixel
sized font of cinema.
# Without labels
my $map = Image::WorldMap->new("earth-small.png");
# With labels
my $map = Image::WorldMap->new("earth-small.png", "maian/8");
add
This adds a node to the map, with an optional label. Longitude and
latitude are given as a decimal, with (0, 0) representing a point on the
Greenwich meridian and the equator and (-180, -180) top-left and (180,
180) bottom-right on a projection of the Earth.
$map->add(-2.355399, 51.3828, "Bath.pm");
draw
This draws the map and writes it out to a file. The file format is
chosen from the filename, but is typically PNG.
$map->draw("text.png");
NOTES
This module tries hard to make sure that labels do not overlap. This is
an NP-hard problem. It currently uses a simulated annealing method with
Inline::C to speed it up. It could be faster still.
The label positioning method used is random: if you run the program
again, you will get a different set of label positions, which may or may
not be better.
COPYRIGHT
Copyright (C) 2001, Leon Brocard
This module is free software; you can redistribute it or modify it under
the same terms as Perl itself.
AUTHOR
Leon Brocard, acme@astray.com