GPS Race Course Measurements in the News Again

Kevin,

This was the St Davids Day Half Marathon in Newport. 1 March 2015. A lot of GPS tracks were around 12.8 miles. Now, we all know that GPS tracks if anything tend to read slightly long, so a consistent pattern of distances short by 2% is certainly highly suspicious. The first thing done was a check of gps against the course map, and this did not reveal any significant short cuts of the advertised route. Usually when we get claims of a short course it is course layout by the organisers which we find to be at fault. But this was not the case here. The measurement secretary for Wales did a check measurement last Wednesday, and I received his report on his investigation early this morning. He found the course to be 636 metres short (~3%). I suspect that contributing in a major way to the original under measurement was a mistake in the adjustment process (adding in stead of subtracting a distance).

We certify over 400 new courses each year and there has only been one other that I can recall in recent times being found short due to a measurer's mistake. In most cases of suspected short courses investigations show the proper course was not followed.

The thing I found most interesting is the fact that GPS measurements from participants were correct. Generally participant GPS readings are all over the place. This time they got it right!
UPDATE: Newport half marathon was 636 metres short -3/24/15 - South Wales Argus News - http://www.southwalesargus.co....as_636_metres_short/