I assume the calibration course would measure as 1000.0774 ft ( 304.8236 meters ) at 68 degrees F.
The marathon course is 497825 counts / 11.779764 counts per meter = 42,261.03 meters
If the temperature is above 68 degrees F when I measure a calibration course, I may not adjust the length for temperature. A validation should always adjust for temperature.
Dale Summers