Calculating Elevation Gain for any given run or run segment is more complex than simply taking the difference between the elevation at an endpoint and start point. We often get questions from users trying to apply this method by looking at run like this:
The start point has an elevation of 148m, and the endpoint has an elevation of 158m, but the gain only reads as 8m. Why is this?
The first reason is that elevation gain is calculated using not just the start and endpoints but also considers smaller gains in the middle of the data.
Secondly, at Stryd we’re often calculating elevation gain from GPS data, which is imperfect and can be quite noisy or be inaccurate. In order to correct for this noise, we apply filters to the data to allow for more accurate calculations.
The calculated Elevation Gain number you see in PowerCenter is using this corrected data, rather than the raw data that is visible in the graph. This means that the Elevation Gain and Grade numbers in the summary stats are more accurate than what you would obtain by subtracting the start and elevation points.
If you’d like to learn more about different methods of calculating elevation gain, I recommend this article from GPS Visualizer as a good starting place. We don’t use the same methods of correction as mentioned in that article, but it gives a good sense of why elevation corrections are needed when calculating the gain.
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