Indicates whether the longitude of the destination point is East or West longitude. An ASCII value of "E" indicates East longitude, whereas "W" is West longitude.
The default value is an empty string, which means "unknown". An unknown value is not written when saving EXIF values.
Note: To save GPS data, you must set EXIF_GPSVersionID to '2.2.0.0' (or use the const, GPS_Version_ID)