Thank you! That was very interesting. I had assumed that they were interpolating GPS data, but I guess not. It seems they are smoothing it, though. That bein

Thank you! That was very interesting. I had assumed that they were interpolating GPS data, but I guess not. It seems they are smoothing it, though. That being the case, perhaps I should write the program I was thinking of writing. Even though GPS elevation data is really, truly horrible I think you could probably use statistical techniques to get good data with enough GPS traces. Even routes that are mildly popular can have thousands, or tens of thousands of rides per year. Each one of those rides on Strava has GPX data associated with it. I'm sure it would be more than enough. Unfortunately, I have about a million other projects on the go :-P