[Talk-us] exit_to vs destination

[Martijn van Exel]

Hi,

On Sat, Jul 5, 2014 at 11:29 PM, Russ Nelson <nelson at crynwr.com> wrote:
> Paul Norman writes:
>  > It's not impossible - but the devil is, as always, in the details. You
>  > can obviously limit it to only cases where there is a motorway with a
>  > motorway_link branching off and no left/right tags, but it's not just that.
>
> Thinking about all the exit_to's that I've added, the vast majority of
> them could be converted without changing the value from an exit_to on
> a motorway_junction into a destination on the associated
> motorway_link.

My next step would be to identify and count the number of 'simple'
cases where there is one motorway and one motorway_link, a
motorway_junction node with a ref and exit_to, and the exit_to
contains one single destination name, or a list of destination names.
Perhaps also patterns like "UT-201;Parley's Way;UT-269;State Street"?
Then we'd have an idea of how many would be left to manually look at.
>
> And at that point, wouldn't motorway_junction be moot, since there
> ought to be one everywhere a motorway and motorway_link join?

Theoretically, but it's still a useful container for the exit number,
and makes the location of the exit explicit. You could also argue that
every intersection between a highway= and a railway= is a crossing,
but I still think it's nice that it's explicitly mapped as one.

I will follow up with some numbers, unless Paul changes his mind about
this not having much interest and crunches the numbers before me.
-- 
Martijn van Exel
http://oegeo.wordpress.com/
http://openstreetmap.us/