[Talk-ca] Building Import

[Tim Elrick]

I think, Montreal's OSMappers would appreciate to discuss the import of 
the buildings there first on the local list. By the way, John, I have 
never said I would be taking the lead for the entirety of Québec (at 
least, at the moment). However, I feel that the import should be 
discussed on the liste OSM de Québec first.

Danny, I disagree with you on the import of building blocks. I find it 
much more tedious to discern them later, then splitting them into single 
buildings first before importing, because, I think, you need to know 
your neighbourhood very well to find unsplit buildings in the OSM 
database. Doing this for a whole town or even city (like Montreal) would 
take much longer than pre-processing.

As for the rest, I have some understanding for the impatience of 
OSMappers about the moratorium on the import - as quite some time has 
passed and the discussion hasn't really moved on nor has the development 
of the countrywide import plan [1] - last change there was beginning of 
February.

Having looked at the Microsoft data and compared quality to the Open 
Building Database in two places (Montréal, QC and Williams Lake, BC), I 
would suggest to refrain from using it as a source for importing, unless 
you verify them for small areas (but then you can almost draw them by 
hand). In dense areas like downtown Montréal the building footprints are 
in many cases plainly wrong (see my contribution to this list on 
2019-03-02, 19h57 EST), in more scattered areas and suburban landscapes 
buildings are randomly aligned and quite some buildings are missing (my 
unverified estimate is about 5-10%).

As for the Open Building database, it is important to discern the data 
by the sources as each municipality that contributed data might have 
used different methods and has different mapping standards. Now add the 
disagreement on this list about orthogonalization and building details. 
I think, this suggests breaking up the import plan in smaller batches; 
for the start it can be cloned from the original one, but the 
pre-processing and import process might differ due to how data sources 
might need to be treated as well as how local OSM communities would like 
to go forward.

What do you reckon?

Tim

[1] https://wiki.openstreetmap.org/wiki/Canada_Building_Import


On 2019-03-15 14:01, John Whelan wrote:
Which I think comes back to defining the local mappers.

There has been discussion on Montreal as well and not all Ontario thinks 
the same way.  Ottawa local mappers for example have different opinions 
to Pierre and Nate on what is acceptable and I'm under the impression 
that not everyone in Toronto agrees with Nate's position.

We seem to be blocking out parts of the country such as Montreal is this 
a reasonable approach?

Can we find someway to loosely define local groups and their areas of 
responsibility and how to contact them?

For example one small Ontario city has to my knowledge one OpenStreetMap 
mapper who maps very occasionally.  My understanding is they would be 
quite happy to see an import happen but many of the buildings have 
already been mapped although not to the accuracy that the Stats Can data 
offers. How do you deal with these smaller cities and townships?

Thanks

Cheerio John

Paul Norman via Talk-ca wrote on 2019-03-15 1:45 PM:
> On 2019-03-15 9:07 a.m., Andrew Lester wrote:
>> I disagree. Silence won't solve anything.
>>
>> I'm speaking here as a local BC mapper, and I strongly disa gree with 
>> these recent imports.
>
> I'm also a BC mapper, and have only seen the consultation happen over 
> Ontario, not BC.
>
>
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