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Canada Basemap - bridges add junction nodes

Posted: Sun Feb 24, 2013 5:51 am
by doctorkb
Hi all,

I don't remember reading anything about this in the wiki, so I'm wondering on opinions here.

It seems Canada's basemap import added junction nodes at each end of every bridge -- regardless if it is really just a culvert crossing a seasonal stream, or if it is a bridge of significant length.

Is there any consensus on whether these nodes should remain or be deleted? Should we keep both, one or neither?

I'm all for deleting at least one of them when the crossing is shorter than about 20m.

Re: Canada Basemap - bridges add junction nodes

Posted: Sun Feb 24, 2013 11:46 pm
by doctorkb
erablian: I agree in the hunting them down being silly... but I am also not sure if we should be deleting both sides of them.

I just think of parts of the Anthony Henday that have some slow-downs... rather than have the entire segment used for the calculation, it would be nice if it was more specific. Not saying we need to be adding too many extraneous junctions, just that a bridge might be a good thing to have marked as separate... but also don't want to be the only one doing it. :)

Re: Canada Basemap - bridges add junction nodes

Posted: Sun Feb 24, 2013 11:35 pm
by erablian
I delete them as I come across them. But there is no benefit in spending time hunting them down.

Re: Canada Basemap - bridges add junction nodes

Posted: Wed Feb 27, 2013 3:37 am
by james8970
I delete them as I come across them. There is no benefit to keeping them, yet, in my experience, a number of problems have arisen with them in the past. I've seen the arrow incorrectly changed to disabled, naming issues and then there is the possibility of routing issues if the route hasn't been driven a significant amount of times. I think it ought to be best practice to delete them as you come across them, but, like erablian said, it's not worth while to spend a significant amount of time dedicated to tracking them down.

As far as adding junctions to increase penalties along a road, I've done this in very rare circumstances, essentially just on side residential streets that run parallel to a primary street. Often I find high road speed data is incorrectly given to these streets, resulting in bizarre detours down these streets. I'm sure there are a few more exceptions to creating extraneous junctions, but this is the only useful example that comes to mind at the moment.

If Anthony Henday has slow-downs at certain points during the day, the traffic data should be lower to reflect this. I don't feel that additional superfluous junctions should be necessary here, but that's just my opinion.
James

Re: Canada Basemap - bridges add junction nodes

Posted: Sun Feb 24, 2013 2:41 pm
by jasonh300
The U.S. basemap also came with those junctions because the rivers, creeks, streams, etc were also on the basemap. That was just one of the few things they filtered out. As a result, the junctions stayed. They don't serve any purpose (nor does any other extra junction like that) and actually can affect routing by adding a small penalty to the route.

Re: Canada Basemap - bridges add junction nodes

Posted: Sun Feb 24, 2013 4:02 pm
by Timbones
UK basemap has the same.

I think that bridge junctions have a *default* penalty of 5s, but Waze will quickly learn that there's no penalty after a few drives. So, it doesn't really matter if they deleted or not.

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