5
1

I'm looking at http://keepright.ipax.at and trying to correct some of the problems in my area. The majority seem to be "This highway intersects the waterway but there is no junction node". This seems to me to be correct as, unless the waterway routinely flows across the road (a ford!) there is no junction. The renderer seems to draw the road over the waterway in the ones I've looked at so far.

How do you think I should I fix this?
a) Tell keepright that it's a false positive and to ignore it?
b) Give the waterway a layer of -1?
c) Add a junction node but mark it as tunnel=culvert layer=-1 However in some cases I imagine that there is probably a bridge but the mapper has failed to note this in OSM so this is not the most viable/accurate option.
d) Go and check each one out individually, and then...?

I favour option b.

What say you?

asked 15 Feb '11, 02:01

vagabond's gravatar image

vagabond
1954510
accept rate: 0%

1

I would avoid setting layer tags unless you have multiple bridges, or multiple tunnels crossing. Otherwise, let the renderers sort it out, they're pretty good about being able to tell that a tunnel is below the surface, the surface is the surface, and bridges are above the surface. You only really need "layer" tags when you have situations like double-decker bridges on a divided highway, motorway interchanges, major subway stations, and the like, where multiple of the same kind of thing (multiple bridges, multiple tunnels) cross each other.

(17 Feb '11, 06:12) Paul Johnson

15

Why mark it as a false positive when it isn't?

Tunnels should not be marked as a junction nodes, but as ways. See: Key:tunnel

I would suggest d). If the waterway flows in a culvert then enter it as a culvert. If the way runs over a bridge, then enter it as a bridge. If it's a ford, then enter it as a ford. If it's an aqueduct, then enter it as an aqueduct, etc, etc..

I advice against filling the OSM database with guesses just to make our debugging tools happy. The tools are there to help us find issues where we may need to collect more fact.

By the way I'm more worried about how the routing softwares handle those issues, than the prevalence of a minor artefact in a rendered map intended for the human eye. A strict routing software might refuse to route your wheelchair via the faintly defined crossing with the river.

permanent link

answered 15 Feb '11, 02:52

gnurk's gravatar image

gnurk
6.1k106095
accept rate: 15%

edited 15 Feb '11, 02:53

2

Definitely "d". If you've not been to the location, you don't know what's there, do you?

(15 Feb '11, 19:38) SomeoneElse ♦
1

If the waterway and the highway don't actually cross (due to one being on a bridge or the other in a culvert), is an intersection node actually necessary? My understanding is that such a waterway-highway joined node would be indicative of a ford or a boat ramp, where one could potentially turn off the highway and use the waterway as a route if they were operating an amphibious vehicle or not adverse to swimming...

(16 Feb '11, 17:06) Paul Johnson
2

Ways crossing on different layers should not have a common junction node. Otherwise KeepRight will write messages like "This node is a junction of ways on different layers" and "Connected ways should be on the same layer. Crossings on intermediate nodes of ways on different layers are obviously wrong. Junctions on end-nodes of ways on different layers are also deprecated, but common practice. So you may ignore this part of the check and switch them off separately. Please note that bridges are set to layer +1, and tunnels to -1, anything else to layer 0 implicitly if no layer tag is present."

(16 Feb '11, 20:03) gnurk

Yeah, I've found setting the layer tag for those three levels generally does more harm than good in most cases.

(17 Feb '11, 19:08) Paul Johnson

Go and survey the place and map what is actually there.

permanent link

answered 17 Feb '11, 12:28

ChrisH's gravatar image

ChrisH
4.1k134262
accept rate: 15%

I would recommend option C or D:

  • a: is not technically a false positive
  • b: In the past there have been those who go through and made mass "corrections" to waterways having just a layer of -1, on the basis that it's a "Ground level feature". (Which I disagree with)
  • c: You are correct - most are culverts, but many will be bridges
  • d: Just leave them since there is no immediate harm to routing, etc; correct them as they are surveyed.
permanent link

answered 15 Feb '11, 02:56

Mike%20N's gravatar image

Mike N
2.7k21652
accept rate: 17%

edited 15 Feb '11, 02:57

Some of the ways I've been mapping are tracks and trails across moors and many of these will indeed be fords and therefore pukka intersections.

Many thanks for the responses.

(16 Feb '11, 17:00) vagabond

I agree with Paul Johnson, the only nodes where roads/rail should intersect water would be fords (or boat ramps), everything else they should be unattached

There is of course the odd time where the river (canal, ditch) is actually on a bridge.

Of course there is also THIS... canal crosses a river, and Interstate 10 crosses both. Of course it doesn't render accurately. http://www.openstreetmap.org/?lat=30.04535&lon=-94.149314&zoom=18&layers=M

permanent link

answered 25 Aug '11, 23:47

Sundance's gravatar image

Sundance
467511
accept rate: 3%

edited 25 Aug '11, 23:48

You are not entirely right. Osmarender renders it correctly (the bridges).
More importantly it does not seem to be mapped right. The river with riverbanks should have a single way for the flow inside (one that corresponds to the river network topology. And the same goes for the canal. It should be drawn as one waterway=canal only, perhaps bound in natural=water area. If you go east along the canal you get to pipes that are likely used to transfer the canal water over the river, but is not mapped at all and the second river/canal is also not...
+1 for the nice example

(26 Aug '11, 00:13) LM_1

I recommend not taking KeepRight too seriously here. Just turn off the waterway/highway checkbox and be happy:

  • The rendering tools do a fine job of drawing this case.
  • The routing tools are not confused either way.
  • The solutions are often worse than the problem.

If you feel compelled to act, and you know which streams cross at the same level as the road, you can create a junction node and tag it: http://wiki.openstreetmap.org/wiki/Key:ford. In times of high water knowing which road crossings are definitely wet can be helpful.

permanent link

answered 25 Aug '11, 19:51

Bryce%20C%20Nesbitt's gravatar image

Bryce C Nesbitt
34551117
accept rate: 0%

To bad you can't turn off the waterway/highway checking in JOSM. The error messages complaining about crossing ways when there is a way on a bridge over a river are a constant frustration to this user.

(20 Sep '13, 04:44) AlaskaDave
Your answer
toggle preview

Follow this question

By Email:

Once you sign in you will be able to subscribe for any updates here

By RSS:

Answers

Answers and Comments

Markdown Basics

  • *italic* or _italic_
  • **bold** or __bold__
  • link:[text](http://url.com/ "title")
  • image?![alt text](/path/img.jpg "title")
  • numbered list: 1. Foo 2. Bar
  • to add a line break simply add two spaces to where you would like the new line to be.
  • basic HTML tags are also supported

Question tags:

×132
×87
×44
×42
×13

question asked: 15 Feb '11, 02:01

question was seen: 9,682 times

last updated: 20 Sep '13, 04:44

powered by OSQA