code: public static void checkLatLong(double lat, double lon) {
  		checkArgument(lon <= 181.0, "longitude out of range " + lon);
  		checkArgument(lon > -180.0, "longitude out of range " + lon);
  		checkArgument(lat <= 91.0, "latitude out of range " + lat);
  		checkArgument(lat > -90.0, "latitude out of range " + lat);
  	}
docs: Check lat lon are withing allowable range as per 1371-4.pdf. Note that
  values of long=181, lat=91 have special meaning.
  
  @param lat
  @param lon