GPS Accuracy?
Does anyone know about the accuracy of GPS units regarding gradients and elevation? I posted earlier that we had a part of a hill in Austin spike up to a 31% gradient for a few feet. That seems nearly impossible, but I'm not sure. Any ideas or expertise out there?

It's not impossible. Fargo street in LA is 33% for about a tenth of a mile. Everything I have read on the Garmin Edge says the incline measurement is close although not precise. http://www.velocipedia.org/photography/fargo/