I promise I'll try! But could you maybe just give me an example of how to specify the inclusion of a subway edge?
2018-04-26 16:11 GMT-04:00 Nate Wessel <[email protected]>: > Precisely. I would suggest using the profile documentation to build a > simple profile from the ground up. The default profiles are very > complicated and take advantage of some features of the Lua language that > you may not understand when you first look at them. I didn't. I do believe > the profile documentation is pretty complete though; the default profiles > just have a lot of complex stuff built on top of that. > Nate Wessel > Jack of all trades, Master of Geography, PhD Candidate in Urban Planning > SAUSy Lab <http://sausy.ca>, Sid Smith Hall, University of Toronto > > On 04/26/2018 04:00 PM, Patrick Agin wrote: > > And by "handle subway lines", you mean "specify that only subway edges are > included"? > Can I ask you to point in .lua profile where you specify such a thing? In > restricted_highway_whitelist structure maybe? > The readme on profiles seems good but it's general (for example, there is > nothing about this restricted_highway_whitelist). > Do you know where can I find a complete tutorial/documentation on writing > profiles? > thanks again Nate > Patrick > > 2018-04-26 15:30 GMT-04:00 Nate Wessel <[email protected]>: > >> You can use a profile to determine which edges are included in the graph, >> which are accessible, etc. If for example you only handled subway lines in >> the profile and disregarded all other data from OSM, you would only be able >> to match things to subways. >> >> A GPS trace from someone e.g. walking aboveground but parallel to a >> subway track would also likely match to the subway rails because there >> would be no more-likely candidates to match to. >> Nate Wessel >> Jack of all trades, Master of Geography, PhD Candidate in Urban Planning >> SAUSy Lab <http://sausy.ca>, Sid Smith Hall, University of Toronto >> >> On 04/26/2018 02:32 PM, Patrick Agin wrote: >> >> Thanks again Nate, I will take a look for sure. But just out of >> curiosity, what your ttc profile is useful for then? And how do you (in >> general, big picture only) define in a profile that it's subway only? And >> does it mean that when map matching against this profile, only subway >> routes will be returned? >> Patrick >> >> 2018-04-26 12:35 GMT-04:00 Nate Wessel <[email protected]>: >> >>> This one won't return a subway route because I haven't configured it for >>> that. I don't have subway trains in the dataset I'm working with for >>> Toronto. But it would be pretty easy to make a subway only profile, or to >>> add subways into this one if you want to do all transit modes in one >>> profile. Take a look at this page for documentation on how profiles work: >>> https://github.com/Project-OSRM/osrm-backend/blob/master/doc >>> s/profiles.md >>> >>> If you want to understand how map matching in OSRM works generally, I >>> think this paper is a good place to start: >>> https://www.microsoft.com/en-us/research/wp-content/uploads/ >>> 2016/12/map-matching-ACM-GIS-camera-ready.pdf >>> >>> When you change the profile, you're essentially configuring the >>> street/rail/whatever network that your GPS trace will match against. >>> Montreal definitely has subways in OSM; you can see them in the main map at >>> openstreetmap.org. >>> >>> Best, >>> Nate Wessel >>> Jack of all trades, Master of Geography, PhD Candidate in Urban Planning >>> SAUSy Lab <http://sausy.ca>, Sid Smith Hall, University of Toronto >>> >>> On 04/26/2018 10:52 AM, Patrick Agin wrote: >>> >>> Hi Nate and thank you very much for your help. I have a very basic >>> question about your ttc profile (sorry if it's too silly). When you match a >>> GPS dataset against this profile instance, will it return a subway route >>> for example? If yes, why this subway route would be declared much plausible >>> by osrm than the street route? Only because of the ttc profile? I realize >>> that I don't understand very well the involved mechanisms behind osrm and >>> profiles, if you can shed some light on this, I would greatly appreciate. >>> Another question: I suppose that the subway data has to be included in the >>> osm data of my city (Montreal) in order to get subway routes from match . >>> How can I know if it's there or not in my osm data? >>> Thank you again Nate, >>> Patrick >>> >>> 2018-04-26 9:36 GMT-04:00 Nate Wessel <[email protected]>: >>> >>>> I've had some success with transit matching by simply modifying the car >>>> profile to allow routing on streetcar tracks, allowing access for buses and >>>> public service vehicles, etc. Here's a profile I'm using for transit now: >>>> >>>> https://github.com/SAUSy-Lab/retro-gtfs/blob/master/etc/ttc.lua#L347 >>>> >>>> I had also tried to develop a more transit specific profile from the >>>> ground up. My thought was that known transit routes (provided in the OSM >>>> data) would be preferred by modifying their edge weights. This however ran >>>> into an issue with the matching service which hasn't been resolved yet; >>>> edge weights simply aren't used in match results. >>>> https://github.com/Project-OSRM/osrm-backend/issues/4785 >>>> >>>> If anyone has a suggestion for the question about multimodal paths, I >>>> would be very keen to hear it, however I suspect this is still an open >>>> topic of research with no definite best practices. >>>> >>>> Best, >>>> Nate Wessel >>>> Jack of all trades, Master of Geography, PhD Candidate in Urban >>>> Planning >>>> SAUSy Lab <http://sausy.ca>, Sid Smith Hall, University of Toronto >>>> >>>> On 04/26/2018 09:01 AM, Patrick Agin wrote: >>>> >>>> Dear all, >>>> >>>> I'm a newbie to routing engines and my first attempts are with OSRM. >>>> Specifically I want to use the *match *service. Questions I have is : >>>> >>>> 1) is it possible with match service to specify public transport (e.g. >>>> subway) as the mode of transportation? I see only profiles for car, bike >>>> and foot. If not, is there a solution? I'm pretty sure it it possible but >>>> how? I saw in some profiles the public_transport parameter but I don't know >>>> how to use it. >>>> >>>> 2) is it possible for match to return a multi-modal path given the >>>> timestamps of each coordinate? For example, return a sub-path that is the >>>> most plausible for pedestrian (chosen because of the low speed inferred >>>> from timestamps) followed by another subpath that is the most plausible for >>>> car (because of a higher speed)? Or is the only solution to pre-process the >>>> data to infer by myself the mode of transportation and make subsequent >>>> calls to the corresponding profile instance? >>>> >>>> Thanks a lot, >>>> >>>> Patrick >>>> >>>> >>>> _______________________________________________ >>>> OSRM-talk mailing >>>> [email protected]https://lists.openstreetmap.org/listinfo/osrm-talk >>>> >>>> >>>> >>>> _______________________________________________ >>>> OSRM-talk mailing list >>>> [email protected] >>>> https://lists.openstreetmap.org/listinfo/osrm-talk >>>> >>>> >>> >>> >>> _______________________________________________ >>> OSRM-talk mailing >>> [email protected]https://lists.openstreetmap.org/listinfo/osrm-talk >>> >>> >>> >>> _______________________________________________ >>> OSRM-talk mailing list >>> [email protected] >>> https://lists.openstreetmap.org/listinfo/osrm-talk >>> >>> >> >> >> _______________________________________________ >> OSRM-talk mailing >> [email protected]https://lists.openstreetmap.org/listinfo/osrm-talk >> >> >> >> _______________________________________________ >> OSRM-talk mailing list >> [email protected] >> https://lists.openstreetmap.org/listinfo/osrm-talk >> >> > > > _______________________________________________ > OSRM-talk mailing > [email protected]https://lists.openstreetmap.org/listinfo/osrm-talk > > > > _______________________________________________ > OSRM-talk mailing list > [email protected] > https://lists.openstreetmap.org/listinfo/osrm-talk > >
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