[Talk-us] City boundaries on the Canada/US border

Toby Murray toby.murray at gmail.com
Fri Mar 30 15:50:43 BST 2012

On Fri, Mar 30, 2012 at 7:18 AM, Alexander Roalter <alexander at roalter.it> wrote:
> Am 30.03.2012 11:17, schrieb Paul Norman:
>> There are a significant number of cities in BC and Washington which have
>> borders that in practice[1] coincide with the Canada/US border. Currently
>> in
>> OSM these are represented with many nearly-overlapping ways.
>> The Canada/US border here consists of the BC-WA border, BC-ID border,
>> BC-MT
>> border, AB-MT border, SK-MT border, SK-ND border, etc. There are separate
>> ways for the cities on the Canada side and cities on the US side.
> ...
>> This would reduce the number of ways present when you download a section
>> of
>> the border and have many advantages. The one big disadvantage is that it
>> would boost the number of ways in the Canada and US relations. This
>> increases the chance of conflicts and also increases the number of places
>> it
>> could be broken.
> I merged the us/canadian border with the north dakota, minnesota and montana
> state borders and also county borders a while ago, and I agree that there
> should only be one way for one part of the border, this line being shared in
> all affected boundary relations.
> I don't really think this will increase conflicts, as if you delete one way
> of a border, all affected relations will be notified (at least in JOSM it's
> impossible to download a way without downloading all relations this way is
> connected.
> I did include city boundaries where available, but this was the case only on
> one city (Emerson, MB). In Europe, nearly all borders are made up of
> individual municipality border stretches (I once loaded italy's
> circumference, made up of >2500 ways).

The problem with conflicts is if someone is splitting ways that are
members of the US border relation down in Arizona while you are doing
the same up in Washington. But in general I don't think this will be a
huge problem. Much of the US border is either in water or sparsely
populated areas where frequent edits are unlikely.

I've done some splitting of ways for counties along both the north and
south border so I think this would be fine too. Overlapping ways are a
pain to deal with. Then again relations can be a pain too :) But at
least they are cleaner.


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