[OSRM-talk] Some OSRM Match questions

Patrick Niklaus patrick.niklaus at student.kit.edu
Tue Nov 10 23:07:32 UTC 2015


> Which is the recommended way?

Increase the locations limit. Stitching together split traces might
not yield the expected result (start/end points at the split don't
have to match). In general the more data you provide, the better the
algorithm is able to work.

> Are the timestamps used as part of the Hidden-Markov-Model algorithm?

They don't influence the emission probabilities or transition
probabilities, but are used for detecting outliers and gaps (simple
example is driving through a tunnel). You should provide the data if
you have it.

> In my response to a match query I’m getting hint_data.

You can use hint_data as additional input to viaroute. It enables
unambiguous coordinate snapping (important if you want to match first
and then extract additional information). As with viaroute it cannot
be turned off (also adds no real overhead anyway).



On Tue, Nov 10, 2015 at 10:01 PM, Artur Bialecki
<abialecki at intellimec.com> wrote:
>
>
> Hello,
>
>
>
> I’m new to OSRM and I have few question regarding the map matching API.
>
> I’m using version v4.8.1.
>
>
>
> If I have a trip with 1000 locations, what are the implications of setting
>
> –max-matching-size option of osrm-routed as oppose to splitting the trip
>
> into 10 requests with 100 locations each and stitching together the
> responses?
>
> Which is the recommended way?
>
>
>
> The match API takes locations and optional timestamps for each location.
>
> Are the timestamps used as part of the Hidden-Markov-Model algorithm?
>
> Is the match quality or performance affected when using the timestamps?
>
>
>
> In my response to a match query I’m getting hint_data.
>
> The API documentation does not mention this. Is hint_data usable for match
>
> requests? If so how? If not, now do I turn it off?
>
>
>
> Is there a way to turn off logging of requests by osrm-routed, other than
> sending them to /dev/null?
>
>
>
> Is there any documentation on using profile.lua?
>
>
>
> Thank you.
>
>
>
> Artur Bialecki.
>
>
>
>
>
>
>
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