Ruby Mapnik¶ ↑

github.com/mapnik/Ruby-Mapnik

Requirements¶ ↑

• Mapnik 2 (Currently available at svn.mapnik.org/trunk)

• Rice >=1.4.2

• rcairo (github.com/rcairo/rcairo) (Optional)

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¶ ↑

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 libmapnik2.dylib like:

file /usr/local/lib/libmapnik2.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/libmapnik2.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!