This discussion has been locked.

You can no longer post new replies to this discussion. If you have a question you can start a new discussion

Two similar rides showing that the corrected ascent calculations must be wrong.

There seems to be a bug in the corrected ascent computations. I rode the same route, but one with 2 repeated final sub-loops and one with only one final sub-loop. The shorter ride with one final sub-loop gave me a higher corrected ascent value than the longer ride with two final sub-loops. The pressure-based ascent measurement, on the other hand, increased for the longer ride, as expected. See Bloomington Cycling 2x2 vs Bloomington Cycling 2x1.

0 e7andy over 4 years ago

Could you post links to those activities?

0 tjxaires over 4 years ago in reply to e7andy

https://connect.garmin.com/modern/activity/7294414578

https://connect.garmin.com/modern/activity/7294425939

0 tjxaires over 4 years ago in reply to tjxaires

Additional info: The uncorrected ascent numbers are 1250 ft for the longer ride and 1102 ft for the shorter ride. For the uncorrected values, the longer ride has a higher ascent value, as expected.

The "corrected" values are 685 ft for the longer ride and 704 ft for the shorter ride. As you can see, there's a large difference between the "corrected" and uncorrected values. When I corrected elevations on activities years ago, the uncorrected and corrected values were much closer together. This to me lends credence to the theory that a bug has crept into the corrected ascent calculation.

0 e7andy over 4 years ago in reply to tjxaires

The routes are slightly different which could affect the data points that are used for elevation correction.

Compare the elevation graphs here: https://connect.garmin.com/modern/activities

Select both activities and then click Compare.

0 tjxaires over 4 years ago in reply to e7andy

I would think that a route that uses all the same roadways, but does additional loops within the same roadways could only have an increased ascent (and descent) value. If you haven't played the loops, please do. The large difference between the pressure ascent calculations and the map-corrected calculations is also a red herring to me. When I first got this device, 9 years ago, I noticed that the pressure and map-based calculations differed by about 10%. Now they are differing by over 50%.