Originally Posted by
andr0id
Yes, but when you are calculating the MAXIMUM grade over a multi mile climb, you have to pick a interval for intermediate measurements since you can't take the instantaneous grade at every point on the road. And most of the road I've climbed with > 10% grades usually are in crappy shape, so you can probably find different spots on the same parallel that have different grades.
Civil engineers probably figure the grade for some shorter segment like every 100 yards and then pick the steepest of those.
Good point. I'd bet they just look up the US G Surveys. That is a guess, but no point in using the million devices to report what they think it is when your software - and the web APIs exist (I recall they exist) in the cloud.