[Tagging] Classifying roads from Trunk to Tertiary and Unclassified

Joseph Eisenberg joseph.eisenberg at gmail.com
Tue Aug 13 03:19:43 UTC 2019

Right. As Martin, said, while we shouldn't mistag for a better
rendering, it would be great if our tagging would at least make it
possible to have a consistent rendering.

Rather than using highway=trunk to define a autovia, motorroad or
expressway with a certain maxspeed=, lanes=, or surface quality, I
believe it is better to either 1) follow the national classification
system, when this is logical and internally consistent, or 2) use
network relationships and to assign a classification for a complete
road route between towns. Changing the classification from trunk to
primary to trunk again, in the middle of a rural area, breaks the

Certainly mappers should also tag maxspeed=, lanes=, surface=, and
should map divided highways as 2 separate ways, and grade-separated
intersections with bridge= and tunnel= + layer= so that routers will
recognize faster routes.

I'm also in favor of using motorroad=yes and expressway=yes (Actually,
I think these mean nearly the same thing?) in Europe and in the USA
respectively, to define "autovias", "motorroads" and "expressways"

But I don't think it's a good idea if highway=trunk is only limited to
segments of expressway or motorroad, because this leads to an
incomplete network, as in France. It would be nice if you could just
render all highway=primary along with trunk, but in France this still
leads to smaller gaps where primary roads suddenly end.

If each country could develop internally consistent highway classes
that show the network consistently, at some scale, this would help
renders and map users.


On 8/13/19, Martin Koppenhoefer <dieterdreist at gmail.com> wrote:
> sent from a phone
>> On 13. Aug 2019, at 02:21, Warin <61sundowner at gmail.com> wrote:
>> I think your confusing tagging with rendering.
>> Tagging is what is on the ground.
>> The road from Toulouse toward Lyon may physically change between the two,
>> so the tagging follows that (I don't think so but as an example?).
> I believe the issue is that in a proper network you would expect not to find
> gaps at specific zoom levels, when there are actually connections in reality
> (those should show up at the same time (zoom), or not, if you want to make a
> nice network map).
> If classes like motorway or trunk are bound to legal or physical
> characteristics rather than only a hierarchical network, and aren’t
> “complete” from a network aspect, you will get the gaps.
> Cheers Martin
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