[talk-au] Another Melbourne intersection for review

Kim Oldfield osm at oldfield.wattle.id.au
Wed Sep 22 14:00:50 UTC 2021


Hi Andrew,

A couple of days ago I updated this intersection to remove a couple of 
short ways, merge some ways, and update the turn restrictions. There 
should now be only one ways to negotiate the intersection from any entry 
to exit. This may explain why online directions are working, while 
OsmAnd may be using older data.

I haven't see a response to my question of when to use multiple lanes or 
separate ways. In this intersection there are small plastic obstructions 
between lanes. I can see arguments for modelling them either way. For a 
picture of these see 
https://www.mapillary.com/app/?lat=-37.794368611389&lng=145.24075834056&z=17&pKey=1146194895843889&focus=photo 
<https://www.mapillary.com/app/?lat=-37.794368611389&lng=145.24075834056&z=17&pKey=1146194895843889&focus=photo>

Regards,
Kim

On 21/9/21 6:54 pm, Andrew Davidson wrote:
> On 18/9/21 9:04 pm, Kim Oldfield via Talk-au wrote:
>>
>> Andrew, are you familiar with this intersection from travelling 
>> through it?
>>
>
> No, and it may be some time before I could visit in person :-(
>
> I came across this one because it had a broken turn restriction. Based 
> on what had been mapped I assumed that someone was trying to give lane 
> guidance. This is just a standard roundabout except for the fact that 
> you need to be in the left lane to turn left on some of the arms.
>
> OSRM and Graphhopper will give you correct directions (ie take the nth 
> exit on the roundabout) but OSMAnd fails to notice you are going to 
> drive through a roundabout. The first two routers are getting the 
> correct answer by accident because the fake slip roads have been 
> tagged as _link, as a result the router prefer to follow the main road 
> into the roundabout.
>
> It had occurred to me that the same outcome (lane guidance) could now 
> be given using turn and change tagging.
>
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