Declarationproperty EXIF_GPSSpeedRef: AnsiString;
Returns the unit used to express the GPS receiver speed of movement
K: Kilometers per hour
M: Miles per hour
Default value is 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 '220.127.116.11' (or use the const, GPS_Version_ID