[Talk-ca] Municipal boundaries

Bjenk Ellefsen bjenk.ellefsen at gmail.com
Tue Mar 7 18:25:19 UTC 2017


Well noted. Maybe we could start a project out of it a later time with everyone in this thread. It will require research and preparation.

B

Sent from my iPhone

> On Mar 7, 2017, at 11:03 AM, Denis Carriere <carriere.denis at gmail.com> wrote:
> 
> I just want to re-enforce the comment that Kevin Farrugia made.
> 
> Boundaries are one of the most complex features to add in OpenStreetMap. They usually consist of relations that share borders with roads/rivers/other boundaries.
> 
> If ever there is an import of boundaries, the users doing the import have to be VERY experienced with using relations and understand how they work.
> 
> This goes way beyond adding simple building footprints :)
> 
> I'm sure this can be accomplished with the group of people who replied to this thread.
> 
> Documentation is key for this type of work.
> 
> ~~~~~~
> Denis Carriere
> GIS Software & Systems Specialist
> 
>> On Tue, Mar 7, 2017 at 10:36 AM, Bjenk Ellefsen <bjenk.ellefsen at gmail.com> wrote:
>> James, it looks to me those differences are the result of a simplification applied on the processing side.
>> 
>> And I also agree that good enough is usually more problems down the road. We should adopt a standard. The only one I know of for the country is the SGC and Paul is pointing out to an example of how Provinces have defined boundaries.
>> 
>> We probably should look at a standard though if we wish to produce OSM analysis that is consistent and reproducible. The problem I foresee with the use of different and variable boundaries is that it will make OSM data use inconsistent and not accurate.
>> 
>> What I understand form our discussion is that I should do more research on what provinces are using and document this before doing anything and report here. Thanks everyone for the feedback! Any more thoughts?
>> 
>> 
>> 
>> 
>> 
>>> On Tue, Mar 7, 2017 at 10:11 AM, James <james2432 at gmail.com> wrote:
>>> Quebec's Open Data portal just points to the city portals which each have their own license....(usually CC-BY)
>>> 
>>> https://www.donneesquebec.ca/fr/
>>> 
>>>> On Tue, Mar 7, 2017 at 9:42 AM, James <james2432 at gmail.com> wrote:
>>>> We also have to think if we are going with "good enough".... when we want better the work that will be doubled to make the boundaries better.
>>>> 
>>>>> On Tue, Mar 7, 2017 at 9:38 AM, Paul Ramsey <pramsey at cleverelephant.ca> wrote:
>>>>> Municipalities are creatures of the provinces, the most likely source of complete, correct municipal boundaries will be the provincial government, though each municipality will generally know theirs (and sometimes disagree with neighbours, hence the utility of using a provincial file if available).
>>>>> 
>>>>> Matching of CSDs with municipal boundaries is something StatsCan will attempt to achieve, but it's by no means a guarantee. If the goal is "good enough", CSDs are good enough. If the goal is to reflect reality, provincial data will always be preferable.
>>>>> 
>>>>> e.g. https://catalogue.data.gov.bc.ca/dataset/municipalities-legally-defined-administrative-areas-of-bc
>>>>> 
>>>>> P
>>>>> 
>>>>> 
>>>>>> On Tue, Mar 7, 2017 at 6:31 AM, James <james2432 at gmail.com> wrote:
>>>>>> In purple/black CSD 2016, in gold Gatineau's city limits from their open data portal:
>>>>>> http://i.imgur.com/undefined.png
>>>>>> 
>>>>>> The CSDs do not match up with actual city bounds
>>>>>> 
>>>>>>> On Tue, Mar 7, 2017 at 9:20 AM, Bjenk Ellefsen <bjenk.ellefsen at gmail.com> wrote:
>>>>>>> Just to make sure we are talking about the same thing: Census Divisions are higher level and more regional boundaries. CSDs are municipal boundaries (in OSM, level 8).  http://www.statcan.gc.ca/eng/subjects/standard/sgc/2011/sgc-intro
>>>>>>> 
>>>>>>> Can you give me an example of city limits that don't match a CSD or is not in the SGC? Usually, the standard for municipal boundaries are the CSDs. At least, as far as I know, this is the standard geography. When referring to actual city limits, which geographical classification is it referring to?
>>>>>>> 
>>>>>>> Sorry for the questions, I am trying to understand what is the classification used if its not the CSDs.
>>>>>>> 
>>>>>>>> On Tue, Mar 7, 2017 at 9:11 AM, James <james2432 at gmail.com> wrote:
>>>>>>>> Bernie, I've also noticed that StatsCan boundaries seem to be a generalization of an area vs the actual city limits
>>>>>>>> 
>>>>>>>>> On Tue, Mar 7, 2017 at 9:02 AM, Bernie Connors <berniejconnors at gmail.com> wrote:
>>>>>>>>> Bjenk,
>>>>>>>>> 
>>>>>>>>>       In NB there are issues with some census boundaries not matching with our administrative boundaries. The issue I am aware of was with the county boundaries. The census data that is analogous to our county boundaries included some significant deviations to prevent a municipality from being bisected by a county boundary. Please be careful that there is not a similar issue with the CSD boundaries. NB municipal boundaries can be downloaded from the GeoNB Data Catalogue For comparison to the CSD data. 
>>>>>>>>> 
>>>>>>>>> Bernie.
>>>>>>>>> 
>>>>>>>>> Sent from my BlackBerry 10 smartphone on the Bell network.
>>>>>>>>> From: Bjenk Ellefsen
>>>>>>>>> Sent: Tuesday, March 7, 2017 9:51 AM
>>>>>>>>> To: talk-ca at openstreetmap.org
>>>>>>>>> Subject: [Talk-ca] Municipal boundaries
>>>>>>>>> 
>>>>>>>>> Hello, 
>>>>>>>>> 
>>>>>>>>> Municipal boundaries correspond to census subdivisions (CSD). I have seen that many municipalities do not have a boundary yet. Is it ok if I start adding some boundaries based on CSDs? Having the boundaries is important to make extractions and analysis at the municipal level.
>>>>>>>>> 
>>>>>>>>> Bjenk
>>>>>>>>> 
>>>>>>>>> 
>>>>>>>>> _______________________________________________
>>>>>>>>> Talk-ca mailing list
>>>>>>>>> Talk-ca at openstreetmap.org
>>>>>>>>> https://lists.openstreetmap.org/listinfo/talk-ca
>>>>>>>>> 
>>>>>>>> 
>>>>>>>> 
>>>>>>>> 
>>>>>>>> -- 
>>>>>>>> 外に遊びに行こう!
>>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> -- 
>>>>>> 外に遊びに行こう!
>>>>>> 
>>>>>> _______________________________________________
>>>>>> Talk-ca mailing list
>>>>>> Talk-ca at openstreetmap.org
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>>>>>> 
>>>>> 
>>>> 
>>>> 
>>>> 
>>>> -- 
>>>> 外に遊びに行こう!
>>> 
>>> 
>>> 
>>> -- 
>>> 外に遊びに行こう!
>> 
>> 
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