def coordinates_present?(*args)
      args.each do |a|
        # note that Float::NAN != Float::NAN
        # still, this could probably be improved:
        return false if (!a.is_a?(Numeric) or a.to_s == "NaN")
      end
      true
    end
def coordinates_present?(*args)
      args.each do |a|
        # note that Float::NAN != Float::NAN
        # still, this could probably be improved:
        return false if (!a.is_a?(Numeric) or a.to_s == "NaN")
      end
      true
    end
Returns true if all given arguments are valid latitude/longitude values.