[talk-au] [EXTERNAL] Re: Join roundabouts

Nemanja Bracko (E-Search) v-nebrac at microsoft.com
Thu Apr 9 10:39:06 UTC 2020

Hey Warin,

Thanks for the reply!

I just want to clarify my initial post where I have stated:
In the same time, “intersecting” members haven’t been added, so the relation is invalid;
I don’t mind if users add intersection node after joining ways – no problem!
But there is an issue when everything is merged into one way, but without “intersection” member – which can be only a node.

However there are rare edge cases where we are forced to make a split – I have gave an example later. Also some of the attributes such as lane information will also be lost after joining – since number of lanes are different on each part of the roundabout – more often case than I have presented with the destination signs.


From: Warin <61sundowner at gmail.com>
Sent: Thursday, April 9, 2020 12:25 PM
To: talk-au at openstreetmap.org
Subject: Re: [talk-au] [EXTERNAL] Re: Join roundabouts

On 9/4/20 5:40 pm, Nemanja Bracko (E-Search) via Talk-au wrote:

Hi everyone!

Thank you all for responding to this thread.

Thank you Harvey for suggestion to contact them directly, and we left comments on changesets.

I am really sad when someone claims that we are trying to adapt OSM to our needs, instead of adapting to OSM. I can strongly confirm that statement is not true at all, and we are trying to adapt to each country separately because community is doing same things with different approach.

People are people and can be offended where no offense was meant.

The internet has no tone to imply things and some times things written would be better expressed in more kindly words. Just don't take it personally, you'll be much happier if you don't.

Anyway... We are trying to stick to OSM Wiki as much as possible, but in very early days when we were starting AU editing, I had some discussion with Andrew Harvey regarding surface tags and OSM Wiki, and couple of community members and him told me one very useful thing at that time and I really appreciate it: OSM Wiki is not a specification of OSM data, but rather guideline how to use some option or tag. Also it is full of contradictories as well.

Yes the wiki can be very confusing! At best it is a guide and sometimes need careful thought and further exploration into similar features or sub tags to work out the best way to use the tags.

Anyway, back to roundabouts...

When approaching to roundabout, you will see at least one signpost which informs you that you approaching to the roundabout. It will look like this:


Not all roundabouts are so well sign posted.

and then, within the roundabout you have a new signpost which can be totally different than it was before the junction:


Well that sign is actual on the exit road of the roundabout, not the roundabout itself.

While it is visible from the roundabout  not technically part of the roundabout.

This sign is meant to give confidence that you have chosen the correct exit rather than find out miles down the road.

*in this example these are the same.

The reason why do we split it into couple of ways is to properly put direction where it is possible to see the sign for the first time.

Use a node. A way has a length that is less specific than a node.

Davdson said, by OSM Wiki, everything is optional, except member "to". Yes, you are correct, but if you put both of these relations in "to" - how could you recognize which one is before another?

The 'to' will give the order?

The other thing is that if you put first signpost in relation with "to" member only (or with "intersection" and "to" members), but without "from" - destination signpost would be displayed from ANY direction that you are coming from.

In a roundabout all go in the same direction so where you come from is not relevant.



-----Original Message-----

From: Andrew Davidson <theswavu at gmail.com><mailto:theswavu at gmail.com>

Sent: Tuesday, April 7, 2020 11:09 AM

To: Andrew Harvey <andrew.harvey4 at gmail.com><mailto:andrew.harvey4 at gmail.com>

Cc: Nemanja Bracko (E-Search) <v-nebrac at microsoft.com><mailto:v-nebrac at microsoft.com>; OpenStreetMap <talk-au at openstreetmap.org><mailto:talk-au at openstreetmap.org>

Subject: [EXTERNAL] Re: [talk-au] Join roundabouts

On 7/4/20 9:13 am, Andrew Harvey wrote:

I mean when the from member should be the roundabout way, think of a

large roundabout where the destination sign exists on the roundabout

exit, the from is not the leading way it's the roundabout itself.

If the sign is on the exit of a roundabout you can:

1. Tag the outbound way using destination=* 2. Use a destination_sign relationship with a to and intersection member but no from member (it's optional in this case because the destination sign is identical from all inbound directions).

3. Use a destination_sign relation with to, intersection, and from

*node* members. You can use either a way or a node on that way to specify a member of a destination_sign relation.

That's three alternatives to splitting the roundabout way to make a destination_sign relation.


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