Why it is REQUIED to add dot and modify routing graph when two way overlap

[openstreetmap.org-user-d1g]

​http://imgur.com/a/ykxSl

JOSM behaviour is unacceptable. It is wrong in many ways:

1. It forces you to draw dot, when you don't need to
2. It forces you to modify routing graph
3. It forces you to put point with INVALID GPS data

1 and 2 lead to increasing complexity of OSM data processing for routing software. (1-2 turn restrictions to parse). It creates absolutely not needed point without real GPS data linked to it.

[skyper]

Replying to acroq3@…:

​http://imgur.com/a/ykxSl

JOSM behaviour is unacceptable. It is wrong in many ways:

1. It forces you to draw dot, when you don't need to
2. It forces you to modify routing graph
3. It forces you to put point with INVALID GPS data

1 and 2 lead to increasing complexity of OSM data processing for routing software. (1-2 turn restrictions to parse). It creates absolutely not needed point without real GPS data linked to it.

1. anything else is an error. Either missing layer=* plus tunnel=* or bridge=* or the roads cross at a common point.
2. There is still no problem with routing straight and no turn-restriction to parse. Did you have all traffic modes in mind when talking about routing ?
3. We have lots of data from other sources than GPS and if you take your time at the intersection you will have enough GPS data.

This rule is a common practice in OSM and not JOSM specific. Other QA tools have similar test.

[anonymous]

1. There no "common point" in ways AB and CD. If you put point you will make direct routing mistake = make new edges when there none. I just map my way AB in low detail. So it happen to overlap with another low detail path.

My graph is perfectly valid - it routes A->B and C->D. I have no information what between A and B in detail. My road A->B is not connected with any other road. Both A->B and C->D have only layer=0 no tunnels and such.

2. Well yes new graph still routes me A->B and C->D. But after dot added it has invalid (read above) routes A->D, C->B.

3. GPS is primary source in my case and imagery is low res (trees)

[anonymous]

Good news, I was told that this behavoir is options and can be disabled in preferences.xml

<?xml version="1.0" encoding="UTF-8"?>
<preferences xmlns="http://josm.openstreetmap.de/preferences-1.0" version="7211">
<!-- skipped -->
  <list key='validator.skip'>
    <entry value='Ways'/>
  </list>
<!-- skipped -->
</preferences>

I don't have information what need to be changed to make this option skipped by default for all users. This validator feature is harmful if used not wisely. To use this validator feature you must know how: 1. how to create turn restrictions 2. how to check routing (not supported by JOSM out-of-box). These knowledge comes with time and this validator feature must be disabled because there will be consequences (read original issue).

[anonymous]

"Other QA tools have similar test." is not argument to enable by default feature that not only require both knowledge

1. routing graph is not same as highway=* network
2. turn/access/lanes rules
3. turn restrictions
4. how to create and check relation

but also have harmful consequence silently ignored by validator.

[bastiK]

Replying to anonymous:

1. There no "common point" in ways AB and CD. If you put point you will make direct routing mistake = make new edges when there none. I just map my way AB in low detail. So it happen to overlap with another low detail path.

My graph is perfectly valid - it routes A->B and C->D. I have no information what between A and B in detail. My road A->B is not connected with any other road. Both A->B and C->D have only layer=0 no tunnels and such.

2. Well yes new graph still routes me A->B and C->D. But after dot added it has invalid (read above) routes A->D, C->B.

3. GPS is primary source in my case and imagery is low res (trees)

Surely you must know if the 2 ways cross in reality at some point? If so, you should draw a common node at the crossing. (Put a fixme tag when the position is not well known.) If you don't even know that much, you should probably resurvey the area, because basic information would be missing from the map.

[Don-vip]

I'm not sure what you think JOSM is about, but it is designed to map existing features of the real world, based on your knowledge, and not magically guess something from random graph tracing.

If you want to map a single highway, then draw a single highway. If you want to map two crossing highways, then the common node as the intersection is required, this is OSM standard.

[anonymous]

Not real world example? Your "validator" fail to check simplest juntion with two circular roads. It fails so hard.

Do you idea what ​Graph edge is?
You cannot "simply draw dot" here. It will create circular one-sided route that wasn't there (in original version).

[Don-vip]

You're stubborn. Yes we know what a graph is. And JOSM is not a graph drawing software but an OpenStreetMap editor. In OSM, crossing ways are required either to share a common node or be on a distinct layer, that's what this validator test is about.

[anonymous]

Replying to Don-vip:

In OSM, crossing ways are required either to share a common node or be on a distinct layer, that's what this validator test is about.

Can you please link to proposal / agreement then?

Why do I must provide you proofs and screen-shots but you don't? Good matters, close it again.

[Don-vip]

Replying to anonymous:

Replying to Don-vip:

In OSM, crossing ways are required either to share a common node or be on a distinct layer, that's what this validator test is about.

Can you please link to proposal / agreement then?

​osmwiki:Beginners_Guide_1.3.1
​osmwiki:Key:layer
​osmwiki:JOSM/Validator
Help/HowTo/ValidatorExamples

Why do I must provide you proofs and screen-shots but you don't? Good matters, close it again.

Because we're core developers of JOSM for several years while you seem to be a new user. I don't see why you persist to reopen this ticket when multiple authors/experienced users tell you this isn't a problem.

Yes I will close this ticket, once and for all. Please stop to reopen it childly. If you need help to understand OSM basics, there's a lot of documentation on the wiki, mailing lists and/or IRC. Arguing with us on the JOSM bug-tracking system is not the good way to learn.