# File lib/bio/graphics/image_map.rb, line 61
    def to_s
      if @url == ''
        return ''
      else
        return '<area shape="rect" coords="' + @left.to_s + ' ' + @top.to_s + ' ' + @right.to_s + ' ' + @bottom.to_s + '" href="' + @url + '"/>'
      end
    end