[OSRM-talk] Beginner question: default car profile and tracktype/smoothness/surface
Fernando Trebien
fernando.trebien at gmail.com
Mon Mar 17 00:13:57 UTC 2014
I investigated on this idea a bit further. I tried to arrive at
numbers that when multiplied would make sense to me, but in the end
your suggestion of speed limits for each tag made more sense. So,
instead I would now agree with taking the minimum of the following
speeds: default, max, tracktype limit, smoothness limit, and other
things. And I have a new suggestion: we can try to guess tracktype and
smoothness from surface, but only do so when these tags are missing.
I've come to this conclusion after learning what tracktype means
exactly: https://lists.openstreetmap.org/pipermail/tagging/2014-March/016904.html
I've also asked the opinion of the community on this idea:
https://lists.openstreetmap.org/pipermail/tagging/2014-March/016935.html
I'd like to hear your opinion about adding the following code to
https://github.com/DennisOSRM/Project-OSRM/blob/master/profiles/car.lua:
1. Just after the definition of speed_profile (line 34):
-----
tracktype_profile = {
["grade1"] = math.huge,
["grade2"] = 45,
["grade3"] = 30,
["grade4"] = 20,
["grade5"] = 15,
["grade6"] = 9,
["grade7"] = 6,
["grade8"] = 3
}
surface_tracktype_profile = {
["asphalt"] = tracktype_profile["grade1"],
["concrete"] = tracktype_profile["grade1"],
["tartan"] = tracktype_profile["grade1"],
["paved"] = tracktype_profile["grade1"],
["paving_stones"] = tracktype_profile["grade1"],
["concrete:plates"] = tracktype_profile["grade1"],
["metal"] = tracktype_profile["grade1"],
["compacted"] = tracktype_profile["grade1"],
["sett"] = tracktype_profile["grade1"],
["concrete:lanes"] = tracktype_profile["grade1"],
["bricks"] = tracktype_profile["grade1"],
["cement"] = tracktype_profile["grade1"],
["cobblestone"] = tracktype_profile["grade1"],
["wood"] = tracktype_profile["grade1"],
["stone"] = tracktype_profile["grade1"],
["rocky"] = tracktype_profile["grade1"],
["gravel"] = tracktype_profile["grade2"],
["fine_gravel"] = tracktype_profile["grade2"],
["grass_paver"] = tracktype_profile["grade2"],
["unpaved"] = tracktype_profile["grade3"],
["ground"] = tracktype_profile["grade3"],
["dirt"] = tracktype_profile["grade3"],
["grass"] = tracktype_profile["grade3"],
["pebblestone"] = tracktype_profile["grade3"],
["clay"] = tracktype_profile["grade4"],
["sand"] = tracktype_profile["grade5"],
["earth"] = tracktype_profile["grade5"],
["mud"] = tracktype_profile["grade5"]
}
smoothness_profile = {
["excellent"] = math.huge,
["thin_rollers"] = math.huge,
["good"] = 60,
["thin_wheels"] = 60,
["intermediate"] = 45,
["wheels"] = 45,
["bad"] = 30,
["robust_wheels"] = 30,
["very_bad"] = 15,
["high_clearance"] = 15,
["horrible"] = 3,
["off_road_wheels"] = 3
}
surface_smoothness_profile = {
["asphalt"] = smoothness_profile["excellent"],
["concrete"] = smoothness_profile["excellent"],
["tartan"] = smoothness_profile["excellent"],
["paved"] = smoothness_profile["good"],
["paving_stones"] = smoothness_profile["good"],
["concrete:plates"] = smoothness_profile["good"],
["metal"] = smoothness_profile["good"],
["compacted"] = smoothness_profile["intermediate"],
["sett"] = smoothness_profile["intermediate"],
["concrete:lanes"] = smoothness_profile["intermediate"],
["bricks"] = smoothness_profile["intermediate"],
["cement"] = smoothness_profile["intermediate"],
["grass_paver"] = smoothness_profile["intermediate"],
["cobblestone"] = smoothness_profile["bad"],
["wood"] = smoothness_profile["bad"],
["stone"] = smoothness_profile["bad"],
["rocky"] = smoothness_profile["bad"],
["gravel"] = smoothness_profile["bad"],
["fine_gravel"] = smoothness_profile["bad"],
["unpaved"] = smoothness_profile["bad"],
["ground"] = smoothness_profile["bad"],
["dirt"] = smoothness_profile["bad"],
["grass"] = smoothness_profile["bad"],
["pebblestone"] = smoothness_profile["bad"],
["clay"] = smoothness_profile["bad"],
["sand"] = smoothness_profile["bad"],
["earth"] = smoothness_profile["bad"],
["mud"] = smoothness_profile["very_bad"]
}
-----
2. At the beginning of way_function(), just after checking for access
(line 119):
-----
-- we dont route over extremely difficult surfaces
local surface = way.tags:Find("surface")
local tracktype = way.tags:Find("tracktype")
local smoothness = way.tags:Find("smoothness")
-- accept only widely used tracktype values (typos result in inaccessible ways)
if tracktype ~= "" then
if tracktype_profile[tracktype] == nil then
return
end
end
-- accept only widely used smoothness values (typos result in inaccessible ways)
if smoothness ~= "" then
if smoothness_profile[tracktype] == nil then
return
end
end
-----
3. Just before handling forward/backward maxpeeds (line 206):
-----
-- Set the avg speed on ways with difficult surfaces
if tracktype ~= "" then
way.speed = math.min(way.speed, tracktype_profile[tracktype])
else
if surface ~= "" then
if surface_tracktype_profile[surface] ~= nil then
way.speed = math.min(way.speed, surface_tracktype_profile[surface])
end
end
end
if smoothness ~= "" then
way.speed = math.min(way.speed, smoothness_profile[smoothness])
else
if surface ~= "" then
if surface_smoothness_profile[surface] ~= nil then
way.speed = math.min(way.speed, surface_smoothness_profile[surface])
end
end
end
-----
On Mon, Mar 10, 2014 at 11:11 PM, Fernando Trebien
<fernando.trebien at gmail.com> wrote:
> "But if we do want to handle combinations"
>
> Shouldn't we handle them if the community thinks that surface is only
> fully described after adding the 3 tags? Nowhere it is said "use one
> or the other but not both".
>
> The very fact that people don't often combine them means to me that
> one is simply a rough copy of the other and each is adopted by a
> different community.
>
> "maybe use surface (the most used tag), multiplied by a factor if
> tracktype or smoothness is set as well?"
>
> What if both are present? If we multiply by both factors, the final
> result would be lower than expected. In that case, at least averaging
> them would be better (if you're looking for a very simple method).
>
> "In essense, take minimium of:
> - default speed
> - max speed
> - surface speed * tracktype or smoothness factor
> - other things that lower the speed"
>
> Makes sense to me.
>
> On Mon, Mar 10, 2014 at 3:10 PM, Emil Tin <emil at tin.dk> wrote:
>> The tags are not used so often together (from
>> http://taginfo.openstreetmap.org/keys/surface#combinations):
>>
>> Surface (8 077 811 occurences) combinations:
>> 1 087 838 13.47% tracktype
>> 175 011 2.17% smoothness
>>
>> Tracktype combinations:
>> 46 144 1.44% smoothness
>>
>> But if we do want to handle combinations, maybe use surface (the most used
>> tag), multiplied by a factor if tracktype or smoothness is set as well?
>>
>> In essense, take minimium of:
>> - default speed
>> - max speed
>> - surface speed * tracktype or smoothness factor
>> - other things that lower the speed
>>
>>
>>
>> On 10 Mar 2014, at 17:30 , Fernando Trebien <fernando.trebien at gmail.com>
>> wrote:
>>
>> For each tag+value combination, we could assign:
>> - a preference value
>> - a weight value or a priority value
>>
>> When using weights, the final preference value would be a weighed
>> average of the preference values corresponding to each tag.
>>
>> When using priorities, the final preference would be that of the
>> highest priority tag+value combination.
>>
>> Contradictions are an issue, for example:
>> - tracktype=grade1 + smoothness=very_horrible: is it good or is it bad?
>> - tracktype=grade5 + surface=asphalt: is it paved or not?
>> - smoothness=impassable + surface=concrete: maybe the concrete path
>> was very badly built, or maybe we just had an earthquake
>>
>> Weighting would "blur" the contradiction, opting for an average
>> preference of the conflicting values. The greater the contradiction,
>> the greater the risk of poor routing decisions.
>>
>> A pessimist approach (probably "safer" for the user) is to select the
>> lowest preference value assigned for tag+value combinations present in
>> a way. But then, we lose the ability to use one tag as a refinement
>> for the other (for example: tracktype=grade2/3/4/5 when
>> smoothness=bad).
>>
>> A remedy would be a more complex approach which practically encodes
>> the class system that I proposed:
>> - given 3 tag+value combinations, pick the combination with lowest
>> preference value (let's call this tag A)
>> - for the remaining 2 combinations, select those that are considered
>> similar to A (according to some equivalence table) and discard the
>> others
>> - if there are 2 left, also pick the one with lowest preference value (tag
>> B)
>> - possibly pick tag C if it's similar to both A and B
>>
>> The result would be from 1 to 3 tags (A,B,C) from which you'd choose
>> the one with highest priority. That's the most accurate preference
>> value within pessimist choices.
>>
>> A single classification system would eliminate these problems, and it
>> can be introduced in the community (not necessarily in OSRM)
>> simultaneously with a more temporary solution in OSRM using multiple
>> tags and some sort of contradiction handling. I just wouldn't go ahead
>> and propose it if there's no interest in adopting such a thing in the
>> long term.
>>
>> On Mon, Mar 10, 2014 at 11:19 AM, Emil Tin <emil at tin.dk> wrote:
>>
>>
>> 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
>>
>>
>>
>> _______________________________________________
>> 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)
--
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)
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