[OSRM-talk] Beginner question: default car profile and tracktype/smoothness/surface
Emil Tin
emil at tin.dk
Mon Mar 10 14:19:07 UTC 2014
OSRM focuses on tags that are already in widespread use. From tag info:
surface 8077811
tracktype 3212051
smoothness 208379
Even if a new tagging scheme is agreed on (by whom?) it would probably take quite a while before it's in common use worldwide. So for now I think the question is how OSRM should handle these 3 tags.
On 10 Mar 2014, at 14:41 , Fernando Trebien <fernando.trebien at gmail.com> wrote:
> My personal point of view is: they mostly do, but in a needlessly
> complicated way. I think you'd be surprised at how far the discussion
> went (over 150 messages, many of which were quite long) to reach a
> simple agreement: deciding which tags/values to use in order to decide
> which roads are possibly in poor state, as to deserve special
> rendering. In this agreement, we settled on 3 tags (tracktype,
> smoothness and surface) to make such a decision. So it is clear that
> the community views the 3 tags as "necessary" for reasonable routing
> choices when reading the map visually. Trying to take any of the 3 out
> caused strong disagreement from certain people during that discussion.
>
> I tried to condensate my line of thought below, but it yielded a long
> text anyway. To encourage your reading, below is a link to the result
> at which I arrived after brainstorming. It establishes similarities
> with current tags and associating a subjective level of preference to
> each. This level was called "trafficability" during the other debate,
> but since then this name may be inadequate (it was used in a tag
> proposal).
>
> http://i.imgur.com/HUoE1iD.png
>
> In the beginning, I was almost convinced that the "surface" tag would
> be sufficient, but as other opinions came in, I was convinced that
> some of its values are too imprecise. "surface=unpaved", for instance,
> may refer to roads in excellent condition (specially if they'd be
> better described as "surface=compacted"), but also to roads likely in
> poor state (such as in "surface=dirt").
>
> The Australian community seems to be recommending the use of
> "tracktype" for any road type besides highway=track which is what it
> was originally intended for, particularly within the German community.
> But then, many people use the "smoothness" tag for very similar
> reasons. It's easy to establish some rough correspondence between the
> two tags by reading the description of their values. It's easy to
> notice that smoothness provides more granularity at the "good" end of
> the spectrum (3 values representing the best conditions roughly
> correspond to a single value of tracktype) whereas tracktype has
> better precision at the other end (all of its other values correspond
> to a single value of smoothness).
>
> At the same time, the Australian community was trying to introduce new
> values for "tracktype" that correspond to other values of smoothness
> at the "bad" end of the spectrum. If these would not be accepted, they
> would pursue a new tag, "4wd_only=yes/no", that would correspond to
> those values and would be used for special rendering. Nobody seemed to
> be thinking of various transport modes, but some existing tags seemed
> to be doing this: mtb:scale for bikes, sac_scale for pedestrians,
> wheelchair for disabled people.
>
> So I thought: "if there was a single tag to represent all of this,
> would I be able to associate a level of preference to its values, with
> little doubt?" In other words, would the new classification system
> leave less, if any, doubts at all? Would it be sufficiently
> descriptive? It would in my experience, which includes: driving,
> cycling, walking and public transport in Brazil; driving, walking and
> public transport in North America; walking and public transport in
> Australia/NZ; cycling, walking and public transport in various places
> in Europe (England, France, Germany, Netherlands, Austria, Spain). I
> tested myself by associating such values comparatively, after having
> assigned each of the other tags a "class", producing the result I
> provided in the beginning.
>
> The question that I asked myself was: if I had to travel from A to B
> and there were two choices, a 100km-long perfectly flat asphalt road,
> and a shortcut with [surface characteristics here], how many km could
> this shortcut have at maximum to still look like a better choice?
>
> This measure would essentially mean a level of preference and directly
> translate into a coefficient multiplied to velocity in OSRM and other
> routers. Its inverse (1/value) would represent the level of effort.
>
> The obvious problem with this result: these values are my own opinion.
> For a public routing app (such as OSRM), one would have to sample more
> opinions, from people of different nations. But this is easier when
> you have a single tag than with various tag combinations. A single tag
> is also easier to teach and to map (which would encourage more people
> to describe the surface). And it solves well the rendering issues. It
> seems like a win for all involved sides: app developers, mappers, and
> users.
>
> Another little problem: only for class "5-grade2-pebblestone", I've
> forced the value up for thin-wheeled vehicles (bikes and wheelchair).
> The change was less than 10%, but still significant. I did this
> because I believed it would make more sense to have the preference
> curves asymptotically decrease for all vehicle types from one class to
> the next. (This actually suggests that thin-wheeled vehicles might
> require some slightly different classification system.)
>
> Of course I am open to suggestions on how these observations can be
> synthesized into a simpler tagging system.
>
> On Wed, Mar 5, 2014 at 5:17 AM, Emil Tin <ZF0F at tmf.kk.dk> wrote:
>> DO you mean a new osm tag? Doesn't the existing tags you mention cover surface quality?
>>
>> Med venlig hilsen
>>
>> Emil Tin
>> IT- og Processpecialist
>> Trafik
>> _______________________________
>> KØBENHAVNS KOMMUNE
>> Teknik- og Miljøforvaltningen
>> Byens Anvendelse
>>
>> Njalsgade 13 Vær. 118
>> Postboks 380
>> 2300 København S
>>
>> Direkte 2369 5986
>> Mobil 2369 5986
>> Email zf0f at tmf.kk.dk
>> EAN 5798009493149
>> -----Oprindelig meddelelse-----
>> Fra: Fernando Trebien [mailto:fernando.trebien at gmail.com]
>> Sendt: 28. februar 2014 17:35
>> Til: Emil Tin
>> Cc: osrm-talk
>> Emne: Re: [OSRM-talk] Beginner question: default car profile and tracktype/smoothness/surface
>>
>> Thank you Emil and Hans. I didn't know about the biking profile. Even though I'm a cyclist as well, I've been using the website mostly for car routing, and that's what OSRM is most known for here in Brazil.
>>
>> A while ago, I participated in a debate about making OSM-Carto use a different visual style to display roads in "worse than usually expected" state. As the debate developed, I made up a surface classification system that captures similarities among tags that represent "transit effort" (tracktype, smoothness, mtb:scale, sac_scale, wheelchair, 4wd_only, and surface) for various modes of transportation. I wonder if you'd be interested in something along this line, then I would go ahead and propose an official tag for it.
>>
>> On Fri, Feb 28, 2014 at 5:26 AM, Emil Tin <ZF0F at tmf.kk.dk> wrote:
>>>
>>>
>>> Surface is already taken into account for bicycles in the OSRM main repo:
>>>
>>> https://github.com/DennisOSRM/Project-OSRM/blob/master/profiles/bicycl
>>> e.lua
>>>
>>> However, instead of multiplying, I found it more realistic to simply use the surface speed, instead of multiplying:
>>>
>>> surface_speeds = {
>>> ["asphalt"] = default_speed,
>>> ["cobblestone:flattened"] = 10,
>>> ["paving_stones"] = 10,
>>> ["compacted"] = 10,
>>> ["cobblestone"] = 6,
>>> ["unpaved"] = 6,
>>> ["fine_gravel"] = 6,
>>> ["gravel"] = 6,
>>> ["fine_gravel"] = 6,
>>> ["pebbelstone"] = 6,
>>> ["ground"] = 6,
>>> ["dirt"] = 6,
>>> ["earth"] = 6,
>>> ["grass"] = 6,
>>> ["mud"] = 3,
>>> ["sand"] = 3
>>> }
>>>
>>>
>>> -- surfaces
>>> if surface then
>>> surface_speed = surface_speeds[surface]
>>> if surface_speed then
>>> if way.speed > 0 then
>>> way.speed = surface_speed
>>> end
>>> if way.backward_speed > 0 then
>>> way.backward_speed = surface_speed
>>> end
>>> end
>>> end
>>>
>>> Both approaches might have merit.
>>>
>>>
>>>
>>> Kind regards,
>>>
>>> Emil Tin
>>> IT- and Process Specialist
>>> Traffic Design
>>> ________________________________
>>> CITY OF COPENHAGEN
>>> The Technical and Environmental Administration Traffic Department
>>>
>>> Islands Brygge 37 Vær. 118
>>> Postboks 450
>>> 2300 København S
>>>
>>> Telefon +45 2369 5986
>>> Email ZF0F at tmf.kk.dk
>>> EAN 5798009493149
>>>
>>>
>>> -----Oprindelig meddelelse-----
>>> Fra: Hans Gregers Petersen [mailto:gregers at septima.dk]
>>> Sendt: 28. februar 2014 09:16
>>> Til: osrm-talk at openstreetmap.org
>>> Emne: Re: [OSRM-talk] Beginner question: default car profile and
>>> tracktype/smoothness/surface
>>>
>>> Hi Fernando,
>>>
>>>> I've always wondered if there are any plans taking surface
>>>> type/quality into account in the default profiles. I live in a
>>>> developing country (Brazil) with poorly maintained roads and these
>>>> conditions make a big difference at the beginning and at the end of
>>>> many routes if ignored.
>>>
>>> I do not know about the plans regarding the default profile, but I successfully used a simple "factor approach" to surfaces when doing our routing on bicycle paths here in Denmark.
>>> For instance setting the following in the LUA profile:
>>>
>>> -- How much does speed depreciate by surface surface_factors = {
>>> ["unpaved"] = 0.8, ["gravel"] = 0.8, ["cobblestone"] = 0.8, ["dirt"] =
>>> 0.8, ["earth"] = 0.8, ["sand"] = 0.8, ["cobblestone:flattened"] = 0.9,
>>> ["compacted"] = 0.9, ["fine_gravel"] = 0.9, ["wood"] = 0.9 }
>>>
>>> and then later adjuste the speed accordingly:
>>>
>>> -- Surface tag
>>> local surfacetag = way.tags:Find("surface")
>>>
>>> -- Surface factor
>>> if surface_factors[surfacetag] then
>>> way.speed = way.speed * surface_factors[surfacetag] way.backward_speed
>>> = way.backward_speed * surface_factors[surfacetag] end
>>>
>>>
>>>
>>> Best regards,
>>>
>>> Greg
>>>
>>>
>>>
>>> Hans Gregers Petersen
>>> Partner, Senior Consultant
>>> www.septima.dk
>>>
>>> _______________________________________________
>>> OSRM-talk mailing list
>>> OSRM-talk at openstreetmap.org
>>> https://lists.openstreetmap.org/listinfo/osrm-talk
>>>
>>> _______________________________________________
>>> OSRM-talk mailing list
>>> OSRM-talk at openstreetmap.org
>>> https://lists.openstreetmap.org/listinfo/osrm-talk
>>
>>
>>
>> --
>> Fernando Trebien
>> +55 (51) 9962-5409
>>
>> "The speed of computer chips doubles every 18 months." (Moore's law)
>> "The speed of software halves every 18 months." (Gates' law)
>>
>> _______________________________________________
>> OSRM-talk mailing list
>> OSRM-talk at openstreetmap.org
>> https://lists.openstreetmap.org/listinfo/osrm-talk
>
>
>
> --
> Fernando Trebien
> +55 (51) 9962-5409
>
> "The speed of computer chips doubles every 18 months." (Moore's law)
> "The speed of software halves every 18 months." (Gates' law)
>
> _______________________________________________
> OSRM-talk mailing list
> OSRM-talk at openstreetmap.org
> https://lists.openstreetmap.org/listinfo/osrm-talk
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