This interesting question came from an RD for who I measured a couple races:
"..our GIS department has generously offered to mark the GPS coordinates of the start, finish line as well as mile markers of each race. When we were doing the certification I thought I recall you mentioning that USA Track and Field allows for a certain degree of statistical variance of the course? Is that correct and if so what is that distance? The reason I ask is that there are several different levels of GPS equipment available, each with different levels of precision. Obliviously the more precise the better, but based on the below accuracy ranges would you be able to offer your recommendation as to an acceptable level of variance?
- Recreational = within 15 feet
- Mid level - within 3 feet
- High - very precise, down to the centimeter"
The courses are certified and I described them within an inch of a permanent landmark, so I think he's asking about GPS coordinates that would be valid even if utilities and sewer grates were moved in the event of some sort of road construction.
As to his "variance" question, I think he got that from when I explained the two rides had to be within .08% of each other.
As an aside, I use gps coordinates for (non-certified) mile marks that have no easy permanent landmarks.
Comments?
