def google_chart_url
      max = 120
      response = get_all
      return unless response

      historical_data = []
      response.each_with_index do |row, index|
        break if index >= max
        next if row.match(/^#/)

        row = row.split(/  ?/)
        historical_data << row[5]
      end
      return if historical_data.blank?
      historical_data = historical_data.join(',')

      [ self.class.google_chart_base(@buoy_id), '&chd=t:', historical_data ].join
    end
def google_chart_url
      max = 120
      response = get_all
      return unless response

      historical_data = []
      response.each_with_index do |row, index|
        break if index >= max
        next if row.match(/^#/)

        row = row.split(/  ?/)
        historical_data << row[5]
      end
      return if historical_data.blank?
      historical_data = historical_data.join(',')

      [ self.class.google_chart_base(@buoy_id), '&chd=t:', historical_data ].join
    end
Get a graph of the historical data for the given buoy.

 Inspired by:

 https://github.com/thepug/nbdc_graph/blob/master/generate_graphs.py