[OSRM-talk] Strange results from map matching

Frederik Ramm frederik at remote.org
Thu Dec 10 10:49:47 UTC 2020


On 13.05.20 23:14, Sasan Amini wrote:
> I am relatively new in using OSRM for map matching. I got my first
> results but there are two issues that I can't understand. My data has
> 130 rows (points) and in return, I get 150 points! 

I think you are approaching this with the wrong expectation.

The map matching algorithm is not one that simply moves each of your
input points onto the output geometry and therefore has one output for
every input.

Instead, the map matching algorithm tries to answer the question: What
is a valid route on the routing graph that is most likely the basis of
this input GPS track?

This "most likely valid route" is then returned to you. It can have more
or fewer points than the input geometry; in fact matching input geometry
points to certain points on the output will be very difficult!


Frederik Ramm  ##  eMail frederik at remote.org  ##  N49°00'09" E008°23'33"

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