def delete_area(area)
      reset_meta_data
      segments.each do |seg|
        seg.delete_area(area)
        update_meta_data(seg) unless seg.empty?
      end
      segments.delete_if(&:empty?)
    end
def delete_area(area)
      reset_meta_data
      segments.each do |seg|
        seg.delete_area(area)
        update_meta_data(seg) unless seg.empty?
      end
      segments.delete_if(&:empty?)
    end
Deletes all points within a given area and updates the meta data.