ruby_mapnik

= Ruby Mapnik

https://github.com/mapnik/Ruby-Mapnik

== Requirements

• Rake (and extentiontask)
• Mapnik 2.x (Currently available at https://github.com/mapnik/mapnik)
• Rice >= 1.4.2
• rcairo (https://github.com/rcairo/rcairo) (Optional)

On OS X install ruby deps like:

sudo gem install rake-compiler
export ARCHFLAGS="-arch x86_64"
sudo bash -c 'ARCHFLAGS="-arch x86_64" gem install rice cairo'

== Description

A set of bindings between Ruby and Mapnik. Supports many of the common uses for Mapnik, and one day, might support all of them. Rendering is available using the standard AGG library, or additionally via Cairo, if the rcairo gem is installed and Mapnik has been compiled with Cairo support.

== Installation

If you have checked out this local repository code build like:

rake

The above command will compile the bindings and run the tests.

File issues at https://github.com/mapnik/Ruby-Mapnik if you hit any compile errors.

If you wish to install Ruby-Mapnik from the latest tagged release you can do:

gem install ruby_mapnik

Note: on osx the default rake compile will try to build universal, and your mapnik install is unlikely built universal. Check the architecture of libmapnik.dylib like:

file /usr/local/lib/libmapnik.dylib

On a system where your compiler defaults to 64bit you'll see: 'Mach-O 64-bit dynamically linked shared library x86_64'

So to avoid a linking warning like:

ld: warning: ignoring file /usr/local/lib/libmapnik.dylib, file was built for unsupported file format which is not the architecture being linked (i386)

You can pass this before rake compile:

export ARCHFLAGS="-arch x86_64"

== Synopsis

require 'ruby_mapnik'

map = Mapnik::Map.new do |m|

# A grey background
m.background = Mapnik::Color.new('#777')

# Use the Google mercator projection
m.srs =  Mapnik::Tile::DEFAULT_OUTPUT_PROJECTION

# Add a layer to the map
m.layer 'countries' do |l|
  
  # Add a style to the layer
  l.style do |s|

    # Add a rule to the style (this one is a default rule)
    s.rule do |default|
      
      #fill the shapes woith polygon symbolizers
      default.fill = Mapnik::Color.new('#880000')
    end
  end

  # set the srs of the layer
  l.srs = "+proj=latlong +datum=WGS84"

  #specify the datasource for the layer
  l.datasource = Mapnik::Datasource.create :type => 'shape', :file => "#{PATH}/../data/TM_WORLD_BORDERS_SIMPL_0.3_MOD"
end

end

map.zoom_to_box(map.layers.first.envelope) map.render_to_file('my_map.png')

== Examples

See demo/rundemo.rb for the classic mapnik rundemo. Also see demo/sinatra/demo.rb for a simple tile server (requires the sinatra gem).

== Thanks

Thanks to the Mapnik team and especially to Dane Springmeyer!