[OSRM-talk] OSRM-talk Digest, Vol 35, Issue 7

Paul Friedman paul.friedman at streetlightdata.com
Wed Nov 11 17:55:43 UTC 2015


I'm also starting to use this API (and completely love the results).

It appears the default for –max-matching-size is 2.  Is there a reason the
limit is so low (or is it even enforced?)?  Thanks.

---Paul

-----Original Message-----
Date: Wed, 11 Nov 2015 00:07:32 +0100
From: Patrick Niklaus <patrick.niklaus at student.kit.edu>
To: Mailing list to discuss Project OSRM <osrm-talk at openstreetmap.org>
Subject: Re: [OSRM-talk] Some OSRM Match questions
Message-ID:
	<CAFxP+1Pgb_2bx2r=Tahsu0D4W+YurWKpxE33oM6RMZWi=F_C+A at mail.gmail.com>
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> 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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