mercredi 9 août 2017

Elevation gain calculated by software

Hi Trail Boss,

I've seen you post before that BRouter will under report elevation gain while GraphHopper will over report.

On the w/e we did Tabletop/Phelps from the Loj.

BRouter calculates 3494 feet of elevation gain.

GraphHopper calculates 4282 feet of elevation gain.

RideWithGps calculates 3706 feet of elevation gain.

3881 feet of elevation gain is representative of the tracks available at AllTrails. Not that helpful as we don't know what device it was recorded with.

I've also found that trip reports will list vastly different elevation gains for identical hikes. Each poster seems to have complete faith in the device they are employing. I recall that you've posted in the past that a device equipped with a true barometric altimeter is going to produce more reliable results.

Are each of these apps using a different elevation profile to make their calculations? Or are they using the same elevation profile but using a different algorithm?

It doesn't seem that the elevation data is being provided by the map as RideWithGps will report the same elevation gain regardless of the base map utilized.

With the apps reporting such widely varying results I'm guessing elevation gained isn't an easy problem to solve? How do you estimate elevation gained for a route you're planning? Do you trust a routing engine or a recorded track from the field?

When you record a track with Locus do you find the calculated elevation gain to be reliable?

If it's generally understood that BRouter under reports while GraphHopper over reports are either of them working on improving their results?

Thanks,
AP


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