[Talk-ca] Importing buildings in Canada

john whelan jwhelan0112 at gmail.com
Fri Jan 17 19:21:03 UTC 2020


Pierre looking at the Microsoft imports south of the border and their
process is undoubtedly sensible.

I suggest waiting until we have got some movement on the current import
rather than try to tackle to many things at once.

Cheerio John

On Fri, Jan 17, 2020, 1:47 PM Pierre Béland, <pierzenh at yahoo.fr> wrote:

> John,
>
> Exprime tu simplement une opinion, ou as-tu vérifié les procédures
> d'import incluant correction des données et validé la qualité des données
> importées aux États-Unis ? Considères-tu la qualité des données dans la
> base OSM aux États-Unis comparable à ce qui s'est fait au Canada l'an
> dernier ?
>
> La qualité des données Microsoft peut sans doute varier selon divers
> facteurs dont la qualité et précision des données aériennes utilisées.
>
> De mon côté, j'ai regardé du côté de Dallas, Texas. En consultant le
> gestionnaire de tâches US, il est possible d'y repérer les tâches créées
> pour cartographier des bâtiments.
>
> https://tasks.openstreetmap.us/contribute?difficulty=ALL&statuses=ARCHIVED&types=BUILDINGS
>
> Dans ces zones, j'ai constaté en général une bonne qualité des données.
> Je ne connais pas les procédures utilisées, ni regardé le connu des
> fichiers de données Microsoft pour ces zones, mais la tâche ci-dessous
> montre un processus de validation où il était demandé d'orthogonaliser les
> bâtiments.
> https://tasks.openstreetmap.us/project/164#bottom
>
> Pierre
>
>
> Le vendredi 17 janvier 2020 13 h 02 min 20 s UTC−5, john whelan <
> jwhelan0112 at gmail.com> a écrit :
>
>
> > As stated before, I don't consider the Microsoft dataset being close to
> the minimum quality requirements I would expect from any automated
> building entry into OSM.
>
> Well yes that is one opinion but we do have a range of opinions in
> OpenStreetMap and from the number of buildings that have already been
> imported into OpenStreetMap from Microsoft, there seems to be a large
> number in the US for example, it would appear there are those who disagree
> with you which is not surprising given the number of mappers.
>
> To me the buildings are of more interest once they get enriched with more
> tags and the place that happens is in OpenStreetMap.  Streetcomplete I
> think is either the most popular editor these days or very close to it.
> You can't add tags if the buildings are not in OpenStreetMap.  Yes you can
> display the outlines by using the Microsoft data but that does not show
> tags such as building type, building levels, etc etc. and streetcomplete is
> a tool that can be used to introduce OpenStreetMap to many people.
>
> I think perhaps we should concentrate our efforts on the current import
> for the moment but I suspect that some Microsoft buildings will start to be
> imported in Canada even if they don't have an official import plan.
>
> Cheerio John
>
>
> On Fri, 17 Jan 2020 at 12:12, Tim Elrick <osm at elrick.de> wrote:
>
> Hi John,
>
> As stated before, I don't consider the Microsoft dataset being close to
> the minimum quality requirements I would expect from any automated
> building entry into OSM. If you just want to display buildings, you can
> download the MS dataset and use it right away - no need to import into
> OSM. I think, the MS dataset has value as proof of concept and to count
> the number of buildings in a given area (e.g. to estimate market size
> for roofers, estimate number of persons living there for desaster
> relief, etc.). I also think, when Microsoft feeds its algorithm with
> higher resolution data than they did (I don't recall, but I think they
> only used the regular Bing data) they will probably end up with building
> footprints that will meet our/my quality requirements for import into
> OSM one day.
>
> For me, the value of OSM is having accurate information in terms of tags
> and geometry. Otherwise, we could join Wikimapia; they don't care too
> much about geometry accuracy but emphasize on content/tags of objects.
> Pretty interesting project, but different from OSM.
>
> Cheers,
> Tim
>
> On 2020-01-17 10:40, john whelan wrote:
>   >first, to add missing buildings (if it were
> just for this purpose we could also use the much bigger Microsoft
> dataset)
>
> I can't resist.  Does this infer that for parts of the country without
> Stat Can data we are happy to import Microsoft dataset buildings as is?
> Or would we wish to wait until we have some more imports done before
> looking at preprocessing them in some way first.
>
> Thanks John
>
>
>
> On Thu, Jan 16, 2020, 10:11 PM Tim Elrick, <osm at elrick.de
> <mailto:osm at elrick.de>> wrote:
>
>      I would assume in most cases the imported building footprint will be
>      more precise than existing data. For me, this would be a reason to
>      replace already existing objects. However, I think this is a case by
>      case decision. However, I think it is important to keep tags and
>      history
>      of buildings already existent in OSM. This is how I would
>      read/interpret
>      the import guideline stated by Nate: "If you are importing data where
>      there is already some data in OSM, then *you need to combine this
> data*
>      in an appropriate way or suppress the import of features with overlap
>      with existing data." (emphasis added by me)
>
>      However, that just means, the import, hence, is nothing easy and could
>      not be achieve quickly, I would assume. One way of making sure that
>      this
>      is dealt with diligently, would be setting the tasking manager to
>      'experienced mappers only'. We would have to ask James, who is in
>      charge
>      of the Canada Tasking Manager, how to edit/set up the 'experienced
>      mapper role' in the TM. It might be possible to feed in a list of
>      mappers manually or to set a threshold of objects/changesets that they
>      must have entered in OSM. However, maybe only mappers who feel
>      experienced enough to handle the import would contribute to the TM
>      project anyway and we let everyone judge on their own and don't
>      restrict
>      access.
>
>      If we were to separate the new and overlapping buildings, I am also
>      leaning towards Daniel's assessment. I would be afraid to cause more
>      issues than by doing it all at once (with a reasonable tile size, of
>      course).
>
>      In the end, the main point of importing this specific dataset fulfils
>      two purposes, in my opinion: first, to add missing buildings (if it
>      were
>      just for this purpose we could also use the much bigger Microsoft
>      dataset), second, to get the best geospatial representation possible
> in
>      our OSM database. That means, we defer from using the Microsoft
> dataset
>      and use the much higher quality data from the ODB. This also means
> that
>      we should replace already existing buildings (yet keeping tags and
>      history) wherever the ODB footprint is more precise than the
>      existing one.
>
>      Just my two cents here,
>      Tim
>
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