User talk:Imagic/LaneMapping

Motorway with links and destinations - part 5

What about a simple turn=merge_to_left here? We could define that it merges the right-most lane by default (and similar default for simple turn=merge_to_right). Because this case is a frequent one (e.g. when roads join via acceleration lane), the simplied tagging would be less prone to errors, making the common case easier. At least I have already made two times a mistake when tagging merge_to_left... --Martinq 22:02, 12 March 2012 (UTC)

This would be inconsistent, because any osm-key always relates to all lanes, if not specified with :lane. For example turn=right on a road with two lanes means that both lanes are right-turn lanes. But you are correct, that this is a very common case and we should think about some simplifications. What mistakes exactly did you make? --Imagic 08:01, 13 March 2012 (UTC)

True, is really inconsistent. Idea revoked.

My mistake: On oneway roads I tagged lanes from right to left (not left to right), which resulted in merge_to_left|none|none for a simple acceleration lane. In general the lane tagging is a little bit vulnerable to such slips, it's easy to mess up with lane orders when looking at aerial images, the way direction and additionally using :backward and :forward. Now I am aware of this error when tagging lanes. I think the validators and/or OSMI should take care of this, because the error is easy to detect by a validator (merge_to_left makes no sense on the left-most lane, turn-left makes no sense on the right-most lane if there are other turn lanes, etc.).--Martinq 08:49, 13 March 2012 (UTC)

No road marking / destination

North to Vienna there are no road marking prior such motorway junctions:

• Mapping turn lanes when only sign-posted like this [but not for pre-indicators like "in 1000m"]. There are no further road markings!
• Mapping of middle lane destination Brno;Poysdorf;Mistelbach;Graz;Wien or simply empty?

turn:lanes=left|left;through|through
destination:lanes=Brno;Poysdorf;Mistelbach|?????|Graz;Wien
destination_ref:lanes=A5|A5;S1|S1    (no official key, only 250 uses)

--Martinq 21:28, 13 March 2012 (UTC)

Hm... I guess I mapped something wrong in the past. I always used destination:lanes to tag the ref - but this is obviously wrong. The key destination_ref is not documented, but makes much more sense for this. I will create an example for this.

About destination_ref: I find 32 different users quite impressive for only 250 uses.

The middle lane I would map with Brno;Poysdorf;Mistelbach;Graz;Wien .

Yes, agree.--Martinq 10:09, 14 March 2012 (UTC)

Any suggestions on how to map the countries? They are often also painted on the road. --Imagic 09:25, 14 March 2012 (UTC)

No. But destination_country would follow the logic started with destination_ref. Country codes values are standardized (see wikipedia:ISO_3166-1_alpha-2). I am just scared about the monstrous key length.

Of course a destination namespace would have been the cleaner choice in the past (destination:city, destination:ref, destination:country -- and maybe destination allowing mixtures like destination=A5;CZ;Brno;...), but this is no engineering project and we cannot "refactor" easily.--Martinq 10:09, 14 March 2012 (UTC)

No, we can not refactor. But before using destination_country I would introduce the destination namespace. I don't think that destination_ref is anywhere supported, so it should be not too hard to update those tags. --Imagic 10:21, 14 March 2012 (UTC)