[Talk-us] Trunk

Sat Oct 14 17:57:55 UTC 2017

I use Osmand frequently; the point of the cased-line style of the
trunk & motorway tags is, agreeing with Paul here, to show some degree
of access control. This is in-line with many paper road atlases,
especially older ones. My point was that third-party applications
choosing to use this style is their own pejorative, and we should not
be basing tagging definitions on how third-party apps use the data. In
regard to the trunk debate, I understand and fully respect Paul's
position, but I personally disagree. I'm hoping the debate here will
encourage the US OSM community in getting closer to an agreeable
definition for trunk.

On Sat, Oct 14, 2017 at 10:49 AM, Evin Fairchild <evindfair at gmail.com> wrote:
> To add onto what Bradley was saying about third-party applications, I just
> want to add that I've done some fact-checking about a claim that Paul made
> in a previous email about how Osmand renders trunks under the assumption
> that they are expressways (to be clear, by this I mean divided highways w/
> at-grade intersections). After some fact-checking, this claim receives a
> truth rating of completely FALSE.
>
> Anyway, I looked at how Osmand renders motorways versus trunk and I don't
> know how it is that you, Paul, can say that trunk is assumed to be like an
> expressway  in Osmand's render. That is simply not true. The motorway in
> Osmand, for those who are unfamiliar, is red with a thin blue outline around
> it, whereas trunk is just an orange-red line without any other color
> outlining it. This makes it look more like a single-carriageway road and
> less like an expressway like Paul falsely claims. All it looks like is a
> road that is of higher-importance than primary, and does NOT at all look
> like it could be an expressway. Usually, when maps show a divided highway w/
> at-grade intersections, it looks similar to a freeway, but a different
> color, whereas an undivided two-lane road typically looks nothing like an
> expressway or freeway. Thus, it is complete and utter lie to say that Osmand
> makes the assumption that trunk roads are expressways. I don't know how
> mkgmap shows trunk vs. motorway since I don't have a Garmin and thus cannot
> test it out, but I don't trust that Paul is telling the truth here either.
>
> It's important to make truthful claims here, Paul; from now on, I will have
> a VERY difficult time trusting anything you say. I know what I brought up
> was kind of a side point, but I think it's important to call out BS when I
> see it.
>
> -Evin (compdude)
>
>
> On Sat, Oct 14, 2017 at 10:23 AM, Bradley White <theangrytomato at gmail.com>
> wrote:
>>
>> > The concept of expressway and freeway are reasonably well known
>> > concepts;
>> > it makes a lot of sense to map trunk and motorway to those concepts.
>>
>> I agree with freeways but not with expressways. I have no data to back
>> this claim up, but I'm fairly convinced that, while the average
>> citizen could easily differentiate between "freeway" and "not
>> freeway", they would be hard pressed to do the same with an
>> expressway. Anecdotal, but even when I spent time in the Santa Clara
>> area which has a robust expressway system, I never heard a single
>> person say "and then get on the expressway...", or even the word
>> 'expressway' mentioned outside of it being the suffix of a road name.
>> You're right that it's not a terribly difficult concept to understand
>> and thus map, but I disagree that it's an important concept in
>> explaining the road hierarchy in the US, so much so that we can equate
>> an entire class of importance with them. We have a robust, clearly
>> signposted freeway network in the US. We do not have the same with
>> expressways. Roads tend to go in and out of "expressway" qualification
>> depending on context, traffic levels of connecting roads, and highway
>> budget & design policy. A road being built as an expressway is
>> suggestive of its importance at best, and certainly not indicative.
>>
>> Edmonton has many roads around the east and west of the downtown area
>> that are clearly built as expressways. However, they are only tagged
>> secondary because, fundamentally, you only really need to use them to
>> get around the immediate vicinity. Despite being very high quality
>> roads, they aren't all that important in the grand scheme. I can point
>> to many examples of urban roads that likely meet an expressway
>> definition in my current home city of Reno, including one under
>> construction. It would be absurd to me to tag them as being second in
>> importance only to motorways just because they are well-built roads,
>> because they're unimportant outside of getting around the relatively
>> small Reno-Sparks metropolitan area.
>>
>> The "highway" key is about importance. The only category we have
>> full-stop made equivalent with a type of road design is "motorway".
>> From trunk on down, it is just different grades of importance. These
>> are how the definitions are listed on the 'Key:highway' page, which I
>> consider to be definitive. The fact that the words "trunk", "primary",
>> "secondary", ... are used is an artifact of the UK roots of OSM. Had
>> this project started in the US, the keys would probably be "freeway",
>> "principal_artery", "major_artery", "minor_artery", "major_collector",
>> ... leaving UK users scratching their heads trying to figure out how
>> to adapt these definitions to their own network. In countries with
>> signposted expressway systems, it is meaningful in understanding the
>> road network to equate trunk with expressway, so they do that. I don't
>> think doing the same is meaningful in the U.S. given how much
>> variability and inconsistency there is with how and where expressways
>> are constructed.
>>
>> > Even a lot of renderers make this same assumption:  mkgmap maps trunk to
>> > Garmin's concept of expressway and motorway to freeway.  Osmand, easily
>> > the
>> > most popular data consumer for OpenStreetMap, makes the same assumption
>> > (to
>> > the point that most of it's map painting styles, the only
>> > differentiation
>> > between trunk and motorway is a color pallette shift).  It really
>> > wouldn't
>> > hurt the US community to have a "come to Jesus" moment on this,
>> > particularly when using the MUTCD definitions for expressway and freeway
>> > as
>> > qualifiers for trunk and freeway, makes this relatively easy.  The
>> > corollary to "don't tag for the renderer" is "don't break the renderer".
>> > Highways without access control being excluded from trunk or motorway
>> > isn't
>> > an intrinsically bad assumption to make.  Especially if we come to
>> > agreement on that, we can start having a productive talk on how to make
>> > carto not suck for Americans without breaking it for everyone else.
>>
>> I'm really not that concerned with how third-party applications decide
>> to paint their roads. It's up to them to work with the data we
>> provide, not the other way around. If it is important to Garmin or
>> other applications to translate expressways, this can usually be
>> deduced from other tags, or we can trivially add an "expressway=" tag.
>> I also disagree that the carto in the US is bad, other than our
>> insistence that two-lane are categorically not trunk leaving
>> meaningless splatters of orange around the map at low zoom.
>>
>> Also, apologies ahead of time if I keep breaking the archive
>> hierarchy, I'm not totally familiar with how to drive a mailing list
>> and I have yet to find a guide online that explains how.
>>
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