I would like to add elevation data to existing routes in OSM. The data is quite detailed--I'll be adding a new node for each 20cm change in elevation. What would be the best way to do this? Should I try to add new nodes to existing routes? If I add an entire route, will it be properly conflated with existing data?

Thanks,

asked 29 Dec '11, 15:16

mike80439's gravatar image

mike80439
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I think you need to supply more information. so we can answer this better. e.g. what kind of data, and why do you want to do it?

(07 Jan '12, 01:01) emj

Please don't. We do not collect elevation data in OpenStreetMap, for a variety of reasons.

One of these reasons is that elevation data is inherently raster data - with measurements occuring at certain intervals, and with reference to a fixed latitude/longitude grid. If you were to attach elevation information to individual nodes of a geometry in OSM, then nobody could move that geometry about without also altering your elevation data. Our editors don't support that.

The proper way to deal with elevation is to keep a separate database with elevation data, and then reference a route from OSM with matching elevation data from this second source. This is routinely done with SRTM elevation data but there's no reason why it cannot be done with other sources of elevation information. OpenStreetMap is not suitable as an elevation database.

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answered 29 Dec '11, 15:33

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Frederik Ramm ♦
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May I respectfully disagree.

While F. Ramm is perhaps the most active user here, and me the least, I truly believe there ARE needs for elevation data (keys?), and the argument according to which "moving a geometry will alter elevation" is definitely light to me. We don't displace geometries everyday everywhere, we rather bring minute corrections. And potentially "our editors" could be made to just kill an elevation if the point is moved without reconfirming it: "editors are not OSM" ;-)

I'd suggest proposing this feature (duly prepared) in http://wiki.openstreetmap.org/wiki/Proposed_features

(29 Dec '11, 18:28) Herve5
3

Herve5, I'm not saying that there are non needs for elevation data. It is certainly useful - just OSM is not the right medium, at least not for capturing DEM type of data. There's of course nothing to say against spot heights for mountain tops or passes, or specifying the height of a building or a tower; but trying to capture the altitude profile of a route by adding tags to its supporting nodes is just wrong on so many levels.

(29 Dec '11, 18:32) Frederik Ramm ♦

Take a look at the cyclemap: http://www.openstreetmap.org/?lat=53.4172&lon=-1.9053&zoom=13&layers=C The elevation data is not stored in OSM - it is better to store it elsewhere and superimpose it as shown here. This is also used on GPS devices like this too. To maintain data in 3D (with elevation) adds a huge amount of work that is not needed. GPS receivers have large vertical error.

(01 Jan '12, 20:16) ChrisH

Thanks ChrisH. I recognize "&layers=C" indeed already shows elevations, although at the cost of almost everything else (buildings, streams...)

Hervé

(01 Jan '12, 21:15) Herve5
3

That, like all of the maps on the OSM site, are just examples of what is possible. My point is that the elevation can be added to any map render without holding the elevation data in OSM as you suggest we need.

(01 Jan '12, 21:53) ChrisH

There is working code to combine altitude data from a separate database (eg SRTM) with a route from OSM here: http://wiki.openstreetmap.org/wiki/Route_altitude_profiles_SRTM (this was a Google Summer of Code project years ago). I believe this had at one point been integrated into yournavigation.org but I cannot find it on their site now. Also, folks at openseamap.org are working on something that will allow them to crowd-source the measuring of sea depths; if that turns out to work well it could conceivably be used as the basis for a crowd-sourced DEM as well.

(07 Jan '12, 03:06) Frederik Ramm ♦
showing 5 of 6 show 1 more comments

Work on opendem.info, but from reading what you want to do I would recommend:

  1. publish and link to the dataset that gives you these elevation data.
  2. make tools available to extract height profiles for ways in osm.
  3. document it, and write an article so other people can do it.

Bringing elevation into the core of OSM is a possibility but because it is not compatible with the current data model, it will require modifications to the way OSM works at the moment. This is considerably more work than simply importing a batch of elevation tags which would likely be removed again.

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answered 07 Jan '12, 00:56

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edited 07 Jan '12, 02:58

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Frederik Ramm ♦
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question asked: 29 Dec '11, 15:16

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