See the screen capture and attached ride - neither the sign or the magnitude of the slope match the actual grade of the hills at any point. For example, at the selected point in the ride, I was nearing the top of a short hill - the actual slope was positive, as the Isaac altitude plot shows, but the slope graph shows a slight negative value. The status bar at the bottom on the other hand gives a more reasonable slope value of 6.2%.
Can anyone explain to me:
- Does slope in Isaac mean something other than grade? I.e. 100 * rise / run (https://en.wikipedia.org/wiki/Grade_(slope))
- Could the real time power reported by my PowerPod or the various power calculations offered by Isaac be invalidated by these odd values reported for slope?
- Should I be concerned that altitude is negative for my entire ride? (I live in a low part of the world, but this ride was definitely conducted entirely above sea level!). My starting altitude would actually have been around 35 meters, but I can't see any way to calibrate altitude on the PowerPod before a ride.
- Do I need to re-calibrate my PowerPod? If the tilt calibration is wrong, is there a way to simply override it manually with estimated values, rather than doing another calibration ride?