[pgrouting-users] Looking for map matching software

Stephen Woodbridge woodbri at swoodbridge.com
Tue May 10 10:31:55 EDT 2011

The problem with just snapping points to the network, is that it does 
not take into account the underlying topology of the network or the fact 
that snapping to the nearest segment may not be the right choice 5 or 10 
samples in the future. Think about the problem of a long exit ramp 
paralleling a highway. You may not be certain if you are on the highway 
or the ramp until there is a significant deviation from your assumed 
path by the future tracking of the GPS points.

My end result needs to be a valid and probable path that the vehicle 
traveled. There will be potential errors with respect to the actual path 
traveled when there are multiple equally valid solutions, but the 
computed path needs to be reasonable and drivable with respect to the 
underlying network topology.


On 5/10/2011 9:11 AM, Richard Marsden wrote:
> How were you thinking it would work differently to a 'simple snap'?
> Working with PostGIS, I snap to the nearest node (rather than edge), and
> then also record the distance and add this in to the total. Many
> commercial solutions (eg. Microsoft MapPoint) also do this: Record the
> distance to/from the closest road and add this in to the directions and
> distances.
> Richard (M)
> On Mon, May 9, 2011 at 10:39 PM, Stephen Woodbridge
> <woodbri at swoodbridge.com <mailto:woodbri at swoodbridge.com>> wrote:
>     Hi all,
>     Sorry for cross posting this also on the OSGeo-Discuss list.
>     Do we have any good map matching code around? I looking for
>     something that does more than simple snapping of points to nearest
>     segments. I have read tons of academic papers and played around with
>     some simple algorithms in postGIS. I have the road network loaded in
>     pgRouting.
>     Is anyone working on this? or have a working solutions that they are
>     willing to share.
>     Thanks,
>       -Steve W
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