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Edge 530 and GC web

4137730
over 3 years ago

Got edge 530… created course in garmin connect web Distance 25.97 miles elevation gain 1882 feet. Created the same course in RWGPS distance 25.97 miles elevation gain 2058 feet. Loaded course from garmin connect onto edge 530, edge shows elevation gain will be 2072 feet. Why would edge show the same as RWGPS and not what GC says.
To make things even more interesting, go for an actual ride with edge 530 and Apple Watch. After the ride distance matches within 0.1 miles(speed sensor is used on garmin) and Garmin matches 25.97 miles. Elevation gain: edge 530 : 2080 feet, Apple Watch 1880 feet. So Apple Watch matches GC web and edge 530 matches RWGPS. What am I missing?

  • 0 over 3 years ago

    What are you missing? A sense of proportion. 

    The figures you quote are within 0.5% of each other.

    When using map data, there can be slight differences in predicted gain because of the differences in the embedded elevation data. From memory, when exporting from RWGPS, it cuts down the number of course points, which can slightly straighten curves, etc.

    Barometric elevation is actually measured is on a different basis from the Digital Elevation Model in the map data. Some differences are to be expected. 

  • 0 over 3 years ago in reply to mcalista

    Thank you for your response. I guess I didn’t ask the right question. Let’s forget about RWGPS and Apple Watch for a moment. Garmin connect web shows 1882 feet. Course loaded on Edge and reviewed prior to the ride and it shows 2072 feet. That’s not 0.5% difference. That would be 10% difference. Why is there such huge difference between GC and Edge even before the ride?

  • 0 over 3 years ago in reply to 4137730

    Here is what is going on. In order to give good elevation plots Garmin recommends that 3rd party routes are created with track points every 35 meters.

    If a course is upload to GC that does not meet this requirement then on the export process extra points are added to meet this requirement. This can change the elevation gain values in the course FIT file from what is shown in GC.

  • 0 over 3 years ago in reply to aweatherall

    Thank you! That makes sense. Very much appreciated.

  • 0 over 3 years ago in reply to aweatherall

    Great explanation, thanks! Also seems to indict Apple for wrong elevation #’s. 

  • 0 over 3 years ago in reply to tttedp

    I wouldn’t indict Apple as of yet. If course is planned on GC and loaded on edge, Apple numbers seem to be off after the ride. If I just ride and compare elevation to RWGPS or strava , it is anyone’s guess. Sometimes Apple is close and Edge is off by more than 10%.  Sometimes it is the other way around.  Today’s ride was actually very close by both. What interesting is today’s ride had 4 climbs that edge showed on climb pro and all were between 6 and 8% grade steady climbs each about 1.5 miles long give or take. The rest of the route was relatively flat. Total was a little over 2000 feet up and down. The discrepancy usually occurs when I have a lot of short rolling hills. I’m not sure what I did is right, but  I set edge to record every second. Apple seems to record less often and that might be the reason for discrepancy.