kml_parser.rb

module KmlParser
  def self.parse(xml)
    doc = Nokogiri::XML(xml)
    output = {}
    output[:polylines] = []
    output[:markers] = []
    doc.xpath('//xmlns:Placemark').each do |kmlplacemark|
      if kmlplacemark.xpath('xmlns:LineString').empty?
        point = kmlplacemark.xpath('xmlns:Point/xmlns:coordinates').text.split(',').map{|x| x.to_f}
        icon = doc.css(kmlplacemark.xpath('xmlns:styleUrl').text).xpath('xmlns:IconStyle/xmlns:Icon/xmlns:href').text
        output[:markers] << {
          :style => kmlplacemark.xpath('xmlns:styleUrl').text,
          :name => kmlplacemark.xpath('xmlns:name').text,
          :description => kmlplacemark.xpath('xmlns:description').text.gsub(/\"/,"\\\""),
          :point => point,
          :icon => icon
        }
      else
        coordinates = kmlplacemark.xpath('xmlns:LineString/xmlns:coordinates').text.split("\n").map{|x| x.to_s !~ /,.+,/ ? nil : x.split(',').map{|z| z.to_f}}.compact
        style = doc.css(kmlplacemark.xpath('xmlns:styleUrl').text)
        icon = style.xpath('xmlns:IconStyle/xmlns:Icon/xmlns:href').text
        color = style.xpath('xmlns:LineStyle/xmlns:color').text
        width = style.xpath('xmlns:LineStyle/xmlns:width').text
        output[:polylines] << {
          :style => kmlplacemark.xpath('xmlns:styleUrl').text,
          :name => kmlplacemark.xpath('xmlns:name').text,
          :description => kmlplacemark.xpath('xmlns:description').text.gsub(/\"/,"\\\""),
          :tesselate => kmlplacemark.xpath('xmlns:LineString/xmlns:tessellate').text,
          :coordinates => coordinates,
          :icon => icon,
          :color => "\##{color[2..7]}",
          :width => width.to_f
        }
      end
    end
    output
  end
end

kml_to_json.rake

desc 'KML Related tasks'
namespace :kml do
  desc 'Push out to JSON'
  task :to_json => :environment do
    require Rails.root.join('lib', 'kml_parser.rb')
    xml = File.read(Rails.root.join('lib', 'sites.kml'))
    File.open(Rails.root.join('public','sites.json'), 'w') do |sites|
      sites.write  JSON.pretty_generate(KmlParser.parse(xml))
    end
  end
end