OpenStreetMap

Last august you moved the motorway_junction node of the A4 towards A555 by 100 meters. What was the reason to do that (eg a forum discussion)?

Hi,I changed the old and wrong lane-mapping by mapping all lanes in one road using the :lanes- tags. Because of this, the junction moved to the place, where the road actually splits. As far as I know, this is the way, a junction should be mapped. I hope I could help you with this explanation and it would be nice, if you gave me the link to the discussion in the forum.
Regards

Common in OSM is to set the motorway_junction node (just) before the legal barrier. You can check this out:

1. throughout Europe
2. http://wiki.openstreetmap.org/wiki/Talk:Lane_assist/Examples/Motorway_exit#Setting_the_split_.28location_of_the_motorway_junction_node.29
3. http://wiki.openstreetmap.org/wiki/Tag:highway%3Dmotorway_link

Technically change:lanes could do the same thing. Buy what is wrong with using the common way of mapping?

Cheers, Johan

"The tags belong on the node shared by the motorway_link exit way and the through carriageway/through lanes of the motorway/freeway itself."

This is a quote from your Link: http://wiki.openstreetmap.org/wiki/Tag:highway%3Dmotorway_link

I think there is no better way to describe the position of the node.

And the motorway_link - line starts at the point, where the roads actually split, because everything else would be lane-mapping, which is simply wrong.

Regards

The quote you refer to does not mention anything about the positioning of the motorway exit node. Image 2 on that page does. So IMHO your tagging is not correct. It's better to broaden the discussion: https://lists.openstreetmap.org/pipermail/tagging/2017-March/031470.html

“Add a highway=motorway_junction tag at each node Node along a highway with named or numbered junctions where a driver can legally exit, onto a highway=motorway_link, highway=trunk_link or other road class. >>This node should be positioned as the last point before the splay at which it is still possible to make a smooth turn<<.“
From: http://wiki.openstreetmap.org/wiki/Tag:highway%3Dmotorway_junction

That's the correct text: 'where a driver can legally exit'. It's not legally allowed (nowhere in Europe as far as I know) to cross a solid line.

Haven't checked the node (which?) yet, however I'd also prefer to have the split at the physical separation and not the legal separation.
As the wiki talk page shows, that seems to be controversial, though.

Hi, since i'm currently working on my bachelorthesis, I'm not able to answer everyone of your comments in every of my changesets. In a few weeks, I will have more time to discuss this problem, but until then I want to state two points:
1) I think my way of tagging is way more better than the lane-tagging
2) In my opinion, the motorway_junction - tag schoud be at the note, where the lanes split, because only on this way the router can combine the information from the turn with the information of the exit for giving informations like "please leave the motorway on exit xy"
I also think, this is the common tagging-way, at least in germany.

I agree with hsimpson. Exit lanes are never mapped as separate ways but tagged using turn:lanes=*.

Kreuzschnabel, have you ever used a PND in a car on a motorway?

Sure, regularly for years. And I am regularly irritated when the device advises me to "turn right now" when the actual turn is still hundreds of meters ahead.

The problem with lane mapping is that the PND will tell you „go straight ahead“ as soon as it localized you within the correct lane (or "way" in its own image of the world, thinking you’re on an isolated carriageway now), meaning "follow this way". This is irritating for users since it might as well mean, "don’t take this exit" and panickingly pull off the exit lane again, regardless of the solid lane, and get wrong.

Let's assume that the PND tells you to take the exit to Köln in 600 meters. What does that mean to you as a cardriver?

That means to me that the ramp to Köln will branch off the main road in 600 metres, and so I should get into the matching exit lane in time.

Agree. Now suppose, in the same example (your PND tells you to take the exit in 600 meters), that it's not legally allowed to switch from e.g. the leftmost lane you are driving on to the exit lane because of a continuous white line which is 800 metres long?

I would be in the correct lane already since this won’t be its first announcement on this exit. The lane assistant would have told me to get into the rightmost lane miles before, so I would be a dumb driver to stick in the leftmost lane when I’m that close to the exit.

Fully agree with hsimpson and kreuzschnabel on my practical experience using OsmAnd, and find the calculation by 'its so funny' rather theoretical.
The satnav device is just part of the information I process as a driver.

I have experience with TomTom, Navigon, Google Maps and Garmin. They all use the legal motorway_junction point for their routing. So I don't think my example is hypothetical, but standard practice for PND's.

And one other thing: I think it's a pity that the motorways in Germany are being mapped so incosistently now. I have checked about 20 of them throughout Germany (eg Berlin, Munich), and they all have the motorway_junction node on or just before the legal point of exit. My German is not so good, but it might help if one of you starts a discussion on the German forum about this.

You’re welcome to join the discussion on the German forum: https://forum.openstreetmap.org/viewtopic.php?id=57585
No problem if you prefer to express yourself in English, just do so.

Thanks, I'll post my comment there