Yeah, it's understandable that the real world is messy and user-sourced data can be very suspect.
The case I'm thinking of is the eastern end of SR-520 over Lake Washington in the Seattle area. It has hundreds/low thousands of bicycle crossings/day (so surely dozens of Garmin users/day), the background is a dammed freshwater lake with a well known elevation, and clear view of the sky. Yet the elevation data is garbage somehow.
It doesn't really matter for planning purposes as any alternative has such a huge delta but it does signal that user data isn't being utilized to refine their data set even on high volume segments.
The case I'm thinking of is the eastern end of SR-520 over Lake Washington in the Seattle area. It has hundreds/low thousands of bicycle crossings/day (so surely dozens of Garmin users/day), the background is a dammed freshwater lake with a well known elevation, and clear view of the sky. Yet the elevation data is garbage somehow.
It doesn't really matter for planning purposes as any alternative has such a huge delta but it does signal that user data isn't being utilized to refine their data set even on high volume segments.