[OSM-dev] ［Building Lane Model for OSM］How can I get multiple gpx from osm for repeated roads?

[Matt Amos]

On Thu, Nov 17, 2011 at 4:47 PM, donglai <donglai at csail.mit.edu> wrote:
> Hi all:
>
> I'm thinking to build the lane model for OSM using machine learning
> techniques. How can I get multiple gpx files from osm database for certain
> roads?

the GPX tracks in the OSM database are not explicitly related to the
roads - it is a completely different dataset in that regard. to
download tracks for an area of interest, there is the "trackpoints"
API call [1]. however, for bulk downloading large areas there is no
good method (yet). perhaps using the trackpoints API call near some
major intersections would yield the data you need?

cheers,

matt

[1] http://wiki.openstreetmap.org/wiki/API_v0.6#Retrieving_GPS_points

> Thanks in advance for any advice or feedback.
> Best
> D.
>
> Below are my half-baked ideas:
>
> 1) Motivation:
>
> a) According to Sebastian Thrun, in order to build the autonomous driving
> car, they push google map to 15cm accuracy with lane models !!! (I guess
> they do it in an expensive way, maybe only for part of CA to test their car)
> http://www.youtube.com/watch?v=bp9KBrH8H04
>
> b) Also, several OSM members have already proposed the lane tag for the map.
> However, it'll be a pain for our dear brave volunteers to track and mark the
> lane they were in.
>
>
> 2) One possible way out:
> a) the bottleneck is that gpx files uploaded by users are often too noisy to
> figure out the lane assignment. But we have the "turn constraint" (change to
> inner/outer lane before turning left/right) and relative geometry shape of
> the route.
> b) Given multiple gpx files for one road segment, we can have a robust
> estimation of the lane model using machine learning techniques.
> c) Also, such technique may be useful for map refinement instead of asking
> users to correct by their own where the accuracy is in meters.
>
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