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Let us say a way W belongs to two routes R1 and R2. If W belongs to two relations with ref values R1 and R2, and W itself has ref value R1, what value gets shown in OSM?

CASE 2: Let route R1 be a trunk highway and R2 be a primary highway. What value gets shown in OSM?

CASE 3: Let route R1 be a primary highway and R2 be a trunk highway. What value gets shown in OSM?

asked 09 Aug '13, 08:37

madnag4u's gravatar image

accept rate: 0%

Don't tag for the renderer. When in doubt, go with a relation, since that's where things are going in the future and you'll be ahead of the curve if you do.

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answered 12 Aug '13, 04:22

Baloo%20Uriza's gravatar image

Baloo Uriza
accept rate: 9%


Good answer. No idea why this was voted down.

(12 Aug '13, 09:09) sleske

There is a difference between "don't tag for the renderer" and "deliberately break the vast majority of renderers". Until the most widespread renderers have road-relation support, omitting a way tag qualifies as the latter.

There is also the very significant issue that, right now, working with route relations is harder for the newbie in all the mainstream editors.

At present, then, saying "use relations only" breaks the map and breaks the newbies. We need patches to fix that, rather than "advanced users" going off and wilfully doing their own thing.

(12 Aug '13, 09:40) Richard ♦

There's a chicken and an egg problem in play, Richard, and given that the renderers aren't changing, and its being used as an excuse to hold back tagging, the eggs need to be broken to motivate folks on the rendering issues.

(12 Aug '13, 14:51) Baloo Uriza

The renderers only aren't changing because the rendering system has been, effectively, broken for a year or two. Now that we have a Carto-based stylesheet (where "now" means "in the last week"!) changes can happen again.

I think you'll start to see more third-party renderers - of which is an early example - start to add road-relation support, and the mainstream renderers follow along in due course. And if you can help the process on its way by (for example) improving road-relation support in iD, so much the better. But dropping way refs is premature until then.

(12 Aug '13, 15:42) Richard ♦

Well then, can i do both? That is, tag the "superior" ways with their proper route numbers (with no semicolon separator) and also add relevant ways into (properly tagged) relations?

That way the current renderers do not break while the future renderers (which might depend on tags in relations) will also work properly.

(12 Aug '13, 17:27) madnag4u

Yes, you can.

(12 Aug '13, 18:47) Richard ♦
showing 5 of 6 show 1 more comments

The 'Standard' style on shows values from the way only. Other renderers may choose to make use of the data in the relation.

Some countries such as the US, where a road can have more than one number (ref), are beginning to adopt a convention where relations are used to store these numbers. However, there is no widespread adoption (that I know of) of using the relation to store clashing highway= values.

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answered 09 Aug '13, 08:50

Richard's gravatar image

Richard ♦
accept rate: 18%

So, does it mean that one has to write the 'ref' value of that route number which has a higher highway hierarchy?

(09 Aug '13, 09:24) madnag4u

Whatever the convention is in your country. In the US I believe they add all the values to the ref tag, separated by semi-colons; I don't know what's done in India.

(09 Aug '13, 09:33) Richard ♦

Yes, here in the US we put all of the values into the ref tag with semicolons. But this is kind of a hack around the fact that doesn't render relations. We have made our own rendering that does use relations and puts proper highway shields on the map:

As for the highway tag, that definitely doesn't go in the relation, just the way.

(09 Aug '13, 17:11) ToeBee

This still seems like a bad hack, since these refs apply to routes that travel over the ways, not the ways themselves, everywhere I've seen. Even in Europe, this is the case. I don't think there's a single E route in the EU that isn't a multiplex of another route. It's time to bury the dinosaur already.

(12 Aug '13, 04:24) Baloo Uriza

"there is no widespread adoption [...] of using the relation" - well, at least in Central Europe, relations are commonly used for long routes. For example. most German motorways exist as relations, because often parts of a motorway will also have different, local names.

(12 Aug '13, 09:19) sleske

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question asked: 09 Aug '13, 08:37

question was seen: 4,789 times

last updated: 12 Aug '13, 20:52

NOTICE: is no longer in use from 1st March 2024. Please use the OpenStreetMap Community Forum