code: def as_geojson(options = {})
        options = {
          :interior_rings => true
        }.merge(options)
  
        ret = {
          :type => 'Polygon',
          :coordinates => [ self.exterior_ring.coord_seq.to_a ]
        }
  
        if options[:interior_rings] && self.num_interior_rings > 0
          ret[:coordinates].concat self.interior_rings.collect { |r|
            r.coord_seq.to_a
          }
        end
  
        ret
      end
docs: Options:
  
   * :interior_rings - whether to include any interior rings in the output.
     The default is true.