4 ms·

Now it would be great to integrate this data into OSM to get navigation for bikes that takes slopes into account: this is the shortest route, this is the fastes

by carlob 12y ago

Now it would be great to integrate this data into OSM to get navigation for bikes that takes slopes into account: this is the shortest route, this is the fastest considering slope, this is the sportiest…

thrownaway2424 12y ago
SRTM data is nearly useless for that purpose. I had a run at this exact application a few years ago and it was quite an exercise in frustration. The resolution of the data is adequate, but there are artifacts related to the way the data was collected and processed. There are discontinuous edges throughout the data. Also, of course, the data is not the elevation along a route. Bridges and other things over or under which one might ride a bicycle must be accounted for externally. Even roads in trenches or cuts need special attention. I think the only way to make such an application work is to combine the elevation data of numerous sources, SRTM being just one. The most valuable source would be the ambient pressure sensors in mobile phones, which are next to useless for absolute altitude but are excellent for relative altitude as you move along a path, and of course they have GPS so you also know the path taken.
- carlob 12y ago
  This is really really interesting. I was curious as to why I hadn't seen any execution of this pretty obvious idea, now I know.
  - thrownaway2424 12y ago
    Not that I'm trying to discourage anyone from solving this problem. That was merely my experience. There probably exists some combination of filtering and cleverness that would get around the discontinuities. But I think you can see from Google's incredibly vague elevation-along-route bike directions that this problem is not easy.
  - maxerickson 12y ago
    http://cycle.travel/ http://cycle.travel/ and https://www.komoot.de/ https://www.komoot.de/ both take elevation into account (and rely on OSM data for routing). I guess they are probably supplementing the SRTM data where possible though (but they are almost certainly falling back to it in places).
    - thrownaway2424 12y ago
      cycle.travel/map is really nice. I remember there was (years ago) a nifty cycling map of the city of Atlanta, which included a unique triangular control that allowed the user to trade off climbing vs. distance vs. safety (on-road or off, bike lanes, etc). It was based on Google tiles and routes but had its own elevation data.
rmc 12y ago
Numerous long time OSM contributors are avid cyclists. Check out http://cycle.travel/ http://cycle.travel/ or http://www.cyclestreets.net/ http://www.cyclestreets.net/
nradov 12y ago
Supposedly Google Maps is already doing this, presumably using some other data set. http://techcrunch.com/2014/05/16/google-maps-adds-elevation-profiles-to-bike-routes-to-help-you-avoid-those-steep-hills/ http://techcrunch.com/2014/05/16/google-maps-adds-elevation-...
- elithrar 12y ago
  Barometric sensors are one potential source - the latest Nexus has one at the least.
phkahler 12y ago
>> Now it would be great to integrate this data into OSM to get navigation for bikes that takes slopes into account: Doesn't OSM have elevation data from GPS tracks people upload? Of course this wouldn't help with most of the US which was imported from an older map.

by carlob 12y ago

thrownaway2424 12y ago

SRTM data is nearly useless for that purpose. I had a run at this exact application a few years ago and it was quite an exercise in frustration. The resolution of the data is adequate, but there are artifacts related to the way the data was collected and processed. There are discontinuous edges throughout the data. Also, of course, the data is not the elevation along a route. Bridges and other things over or under which one might ride a bicycle must be accounted for externally. Even roads in trenches or cuts need special attention. I think the only way to make such an application work is to combine the elevation data of numerous sources, SRTM being just one. The most valuable source would be the ambient pressure sensors in mobile phones, which are next to useless for absolute altitude but are excellent for relative altitude as you move along a path, and of course they have GPS so you also know the path taken.

carlob 12y ago
This is really really interesting. I was curious as to why I hadn't seen any execution of this pretty obvious idea, now I know.
- thrownaway2424 12y ago
  Not that I'm trying to discourage anyone from solving this problem. That was merely my experience. There probably exists some combination of filtering and cleverness that would get around the discontinuities. But I think you can see from Google's incredibly vague elevation-along-route bike directions that this problem is not easy.
- maxerickson 12y ago
  http://cycle.travel/ http://cycle.travel/ and https://www.komoot.de/ https://www.komoot.de/ both take elevation into account (and rely on OSM data for routing). I guess they are probably supplementing the SRTM data where possible though (but they are almost certainly falling back to it in places).
  - thrownaway2424 12y ago
    cycle.travel/map is really nice. I remember there was (years ago) a nifty cycling map of the city of Atlanta, which included a unique triangular control that allowed the user to trade off climbing vs. distance vs. safety (on-road or off, bike lanes, etc). It was based on Google tiles and routes but had its own elevation data.

rmc 12y ago

Numerous long time OSM contributors are avid cyclists. Check out http://cycle.travel/ http://cycle.travel/ or http://www.cyclestreets.net/ http://www.cyclestreets.net/

nradov 12y ago

Supposedly Google Maps is already doing this, presumably using some other data set. http://techcrunch.com/2014/05/16/google-maps-adds-elevation-profiles-to-bike-routes-to-help-you-avoid-those-steep-hills/ http://techcrunch.com/2014/05/16/google-maps-adds-elevation-...

elithrar 12y ago
Barometric sensors are one potential source - the latest Nexus has one at the least.

phkahler 12y ago

>> Now it would be great to integrate this data into OSM to get navigation for bikes that takes slopes into account: Doesn't OSM have elevation data from GPS tracks people upload? Of course this wouldn't help with most of the US which was imported from an older map.