[pgrouting-users] Looking for map matching software

pgRouting pgrouting-users
1

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

2

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@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

3

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.

Thanks,
   -Steve

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@swoodbridge.com <mailto:woodbri@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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4

Hi Steve,

Please check pgrouting/core/sql/matching.sql - it has a set of
matching (snapping) functions.
For example it can match linestrings to existing road network segments
using routing.
I hope it is what you need.

Anton.