gistfile1.rb

  #
  # Return UTM Zone for a geom
  #
  # Return Integer
  def utm_zone
    geomgeog = srid == 4326 ? self[get_column_name] : transform(4326)
    puts geomgeog.class
    geom = case geomgeog
           when Point then  geomgeog
           when LineString then geomgeog.first
           else
             geomgeog.first.first
           end
    pref = geom.y > 0 ? 32700 : 32600
    zone = ((geom.x + 180) / 6 + 1).to_i
    zone + pref
  end