It is not obvious how accumulated elevation should be calculated. More measuring points give higher elevation in the same sense as the coastline paradox. https://en.wikipedia.org/wiki/Coastline_paradox To be it seems adequate to make one measurments maybe every 2,5 meters, a normal length of a stride while running...

My question: how is OpenStreetMap calculating accumulated elevation? One measurement every xx meters? I have seen that it differs from Google Maps - why?

asked 28 Apr '20, 06:28

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mragel
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OpenStreetMap does not calculate elevation. The only elevation data in OSM is added by users as ele-tag. This is typically done when they see a sign on e.g. the top of a mountain displaying the height.

Why do you think OSM is calculating accumulated elevation? Which map are you consulting that has different results than Google Maps?

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answered 28 Apr '20, 08:45

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escada
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Thanks!

When I let Open Street Map find the way between two locations, I get the distance, and "stigning" and "fall" which (translated from Swedish) is positive and negative elevation. Se the printscreen: www.schackstudion.se/stigning.PNG

It's +18-19 m, and accordning to Google Maps +1-6.

(28 Apr '20, 08:58) mragel
4

The screenshot shows that those results were provided by the GraphHopper routing service. Graphhopper is one of many applications that use OpenStreetMap data but are not directly part of OpenStreetMap. As escada said, there is very little elevation data in OpenStreetMap, certainly not enough for this type of calculation. So GraphHopper must be obtaining elevation data from elsewhere, and using it to carry out this calculation. If you want further details you may need to contact https://www.graphhopper.com/ directly.

(28 Apr '20, 09:24) alan_gr

AFAIK most OSM-related software use SRTM DEM to compute elevation, because it's public domain.

I read this (even if I don't fully understand, I guess that's why you have such a difference with GMaps):

vertical LE90 accuracy ranging between 5–9 m and less than 16 m.

Specifically for Graphhopper, they use different models based on the location, if I understand corrrectly this post.

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answered 28 Apr '20, 17:00

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H_mlet
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edited 28 Apr '20, 17:01

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question asked: 28 Apr '20, 06:28

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