Hello there. In OSM roads are generally lines, but in real life they are often more sophisticated. Is there a way to outline street's shape?

Here is an example:
http://maps.google.com/maps?f=q&source=s_q&hl=pl&geocode=&q=Wroc%C5%82aw&aq=&sll=37.0625,-95.677068&sspn=52.815565,64.951172&ie=UTF8&hq=&hnear=Wroc%C5%82aw,+Dolno%C5%9Bl%C4%85skie,+Polska&ll=51.129741,16.860441&spn=0.002582,0.003964&t=h&z=18

As you see, some nice bus maneuver ground.

Related question: how to draw a bridge which has multiple roads on itself? I have a bridge that carries a car road, tram rails, a pedestrian path and a cycle path. Should I mark them as 4 separate bridges?

asked 10 May '11, 18:06

haael's gravatar image

haael
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accept rate: 0%

edited 12 May '11, 13:55

Pieren's gravatar image

Pieren
9.7k2075157


There is currently no agreed way in OSM to map a highway as a closed area (a polygon) rather than a linear way (a polyline). Indeed, mapping solely as an area would break a lot of rendering and routing software which expects highways to be linear.

The subject is under discussion by some people. However, with the best will in the world, the people discussing it are not developers and so it is not necessarily the case that whatever scheme they devise will ever be adopted by any rendering or routing tools.

Some people, myself included, are of the firm opinion that to do this "properly" would require API-level changes rather than just messily grafting on new metadata within the existing spec. It will also require serious thought as to how the option is presented in editing software while maintaining an understandable and coherent UI.

For now, I would suggest that you map using ways, and if you still have some spare time, find some more stuff to map!

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answered 12 May '11, 19:44

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Richard ♦
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accept rate: 19%

edited 12 May '11, 19:45

1

OK, my solution proposal: add a landuse value: road area. Just like "river" (way) and "riverbank" (area). Roads would still be ways, but if its shape is too sophisticated, it could be outlined by a road area.

(16 May '11, 17:52) haael

Ugh, this was just what other discussed in the link you have given. Silly me.

(16 May '11, 17:53) haael

In OSM, roads/streets/paths etc are mapped as ways. A way is a sequence of nodes (points). A way can have a minimum of 2 nodes, in which case it will be a straight line between the points. If the road is not a straight line, then it is necessary to draw a way with more nodes in it, so it follows the curves more accurately.

How to draw a way or add nodes to a way will depend on which editor you are using. For instructions, you could start by looking at the Beginners' guide or the Potlatch 2 primer or the JOSM guide. For how many nodes to use to map a curve, see the question drawing over traces. Also note that a single road may have to mapped as several separate ways if different tags apply to different parts of it, eg if the name or maxspeed changes.

For bridges, this is probably best asked as a separate question but anyway: If the road, railway and paths are each mapped as separate ways, then each one of them should have a way tagged as bridge=yes. It is true that most renderers will show this on the map as several separate bridges. There is a proposed bridge relation which would group the ways together, and show they are all part of the same bridge, and let you draw the bridge outline. Though this is just a proposal, I don't think it is currently used by any renderers.

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answered 11 May '11, 00:14

Vclaw's gravatar image

Vclaw
9.1k891140
accept rate: 22%

1

I think the question wasn't about straight roads vs curves (which you explained) but on lines vs polygons for roads. You could replace the first couple of paragraphs of your answer with details about streets-as-areas.

(11 May '11, 08:35) Andy Allan

No, no, no. My situation is that a street can not be approximated by a line. It has sophisticated contour.

(11 May '11, 11:50) haael
2

Do you mean that it is not a single line or curve, but in GIS speak a polyline? If that is the case you create multiple ways sharing the same tags. There is no need for a 1:1 relationship between a road/street & an OSM way.

(11 May '11, 12:15) SK53 ♦
2

maybe best if haael can provide a link so we can see the actual street that's causing issues.

(11 May '11, 16:10) Andy Allan

Example no 2:

http://maps.google.com/maps?f=q&source=s_q&hl=pl&geocode=&q=Wroc%C5%82aw&aq=&sll=37.0625,-95.677068&sspn=52.815565,64.951172&ie=UTF8&hq=&hnear=Wroc%C5%82aw,+Dolno%C5%9Bl%C4%85skie,+Polska&ll=51.123117,16.920509&spn=0.001291,0.001982&t=h&z=19

This is harder to see because of the trees, but we have a quite narrow road here that gets wider and one of its tracks is used as a parking. Plus, some nice muddle of footpaths, bike paths and stairs.

The mark for restaurant is few meters off, by the way. Too bad for Google Maps.

(11 May '11, 21:47) haael
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question asked: 10 May '11, 18:06

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last updated: 16 May '11, 17:53

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