[Talk-us] While we're fixing things in iterations

[Andy Townsend]

On 24/09/2020 00:00, Paul Johnson wrote:
>
>
> On Wed, Sep 23, 2020 at 5:56 PM Andy Townsend <ajt1047 at gmail.com 
> <mailto:ajt1047 at gmail.com>> wrote:
>
>
>     On 23/09/2020 23:01, Paul Johnson wrote:
>>
>>
>>     On Wed, Sep 23, 2020 at 4:37 PM stevea <steveaOSM at softworkers.com
>>     <mailto:steveaOSM at softworkers.com>> wrote:
>>
>>         Paul Johnson <baloo at ursamundi.org
>>         <mailto:baloo at ursamundi.org>> wrote:
>>
>>         > 2. Tagging route information on ways.  It's about a decade
>>         too long at this point for ref=* on a way to be completely
>>         disconnected from the entity the tag applies to:  That's why
>>         route relations exist.  Biggest problem child on this at the
>>         moment:  OSM's own tilesets.  Let's drop rendering for ref=*
>>         on ways and just render the route relations already, this and
>>         multipolygons are why relations came to exist in the first place.
>>
>>         Yes, 100% agreement.  I think this is simply pure inertia
>>         (the kind that says "broken process") on the part of renderers.
>>
>>         Can anybody (renderer authors included, maybe even
>>         especially) are welcome to offer reasons why "the old
>>         machinery" remains in place?  Are there legacy use cases that
>>         remain unclear to the wider community?  Please tell us here,
>>         if so.
>>
>     The US is unusual in that it doesn't have a single ref per section
>     of road.  Most places in OSM map what they see on the ground, and
>     the current OSM Carto rendering works just fine for them
>
> Right up until there's more than one kind of route on the way.

No-one's disputing that this is a major problem for mappers in the US - 
I'm just saying that it's really not a major problem in most other 
places.  That doesn't make it any less of a problem in the US but does 
help to explain why people elsewhere seem not to see it as a problem.


>     It's not strictly a Mapnik problem.  It's certainly possible to
>     render information from relations in Mapnik (I've done it, for
>     different sorts of relations, and written diary entries about
>     it).  There are a couple of tricky bits* though:
>
>      1. You'd need to derive the shields from the ref and the road
>         itself from the way, and you're going to get some edge cases
>         where they "don't seem to match".
>      2. I expect that it would be _really_ difficult to render refs
>         from relations in the one country where that's needed and refs
>         from ways in the other 190-odd.  The OSM style is a global
>         style, and that means that local edge cases (which is what the
>         US is here) can't get the "special-case handling" that might
>         be nice.
>
> There's no reason the rest of the world shouldn't be mapping routes 
> this way.  For the reason I gave above.

By all means try and persuade the entire rest of the world to do things 
differently, but I suspect that that will be unlikely to succeed when 
the problem you're trying to solve isn't visible there.

That's why I suggested trying other approaches that would at least 
enable people in the US to see route refs rendered as they would expect 
them to be.

Best Regards,

Andy


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