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Comment by maxerickson | Hacker News Reader

There isn't really support for terrain in OSM. But there probably shouldn't be, there's not really any good way to collect a little bit of elevation data.

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For what it's worth, most GPS chips report elevation (however accurate or inaccurate that may be). It could be as "simple" as using the elevation data in the existing traces, assuming they didn't strip that or fail to save it.

Then again, for common elevation data, there are loads of other good sources which can be used in conjunction with OSM, not sure about licensing though.

The problem with elevations from GPS chips are that they are ellipsoidal heights, that is the height from the surface of the ellipsoid used to model the earth. This can be very far from the elevation referred from mean sea level. I think SRTM is still the best way to get elevation data as mentioned by other commenters.

That explains a lot! After looking at some traces I started to suspect the same. I guess I should've RTFM.

Ah my bad, I'm not familiar with the details of OSM. I figured there'd be some vague support for elevation data so that at least you'd have a nice-ish starting point for modelling a city. Thanks for the clarification though

One approach people have used is to import something derived from SRTM into their rendering system and use that along with OSM data.

http://wiki.openstreetmap.org/wiki/Relief_maps

http://wiki.openstreetmap.org/wiki/Contours

http://www.openstreetmap.org/#map=13/33.9147/-112.4034&layer...

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