[Imports] [Talk-ca] Fwd: [Import] Ottawa Buildings & Addresses [Statistics Canada project]
james2432 at gmail.com
Fri Dec 23 13:49:47 UTC 2016
Also Devon, the city of Ottawa said that they will not be updating the file
provided on their portal as it is only for the StatsCan project to
advance(publicly available) , so for now anyways it's a one time import as
there will never be any other version. The polygons themselves have no
identifiers, so trying to bind them to a building ID would be too
complicated and out of the current scope of the import which seeks to add
missing buildings and update really bad geometries(close enough geometries
will be left as is)
On Thu, Dec 22, 2016 at 1:47 PM, Devon Fyson <devonfyson at gmail.com> wrote:
> Here's are my thoughts on it:
> 1. Arn't the building polygons already available? I see large buildings
> <http://data.ottawa.ca/dataset/large-buildings> and the topographic
> DWG file <http://data.ottawa.ca/dataset/cad-topographic-data> which
> contains buildings.
> 2. If this
> is still the import plan, it should be gone through and updated.
> 3. Should make use of the changeset tags
> Most importantly type and url. For example:
> comment=Import building polygons for Ottawa, Canada. Importing
> non-existant polygons <or> Conflating with existing polygons
> source:date=<date of data. Would be useful when subsequent versions
> are released>
> source=City of Ottawa (maybe should include the dataset such as CAD
> Topographic Mapping Data or Large Buildings)
> source:url=http://data.ottawa.ca/en/dataset/cad-topographic-data (not
> in the list, but I made a comment about it here
> source:license=City of Ottawa Open Data Licence 2.0
> I'm not sure if the tasking manager to JOSM pipeline supports this,
> but if not it's easy to copy/paste all the correct tags in one go under
> "Tags of new changeset".
> 4. use source:geometry=
> <https://wiki.openstreetmap.org/wiki/Key:source:geometry> instead of
> source= tag. Thus if POI information is later added to the polygon,
> it's unambiguous as to what the source refers to.
> 5. I think building replacements (deletions and additions) should be
> done within the same changeset to make it safer. Deleting all the buildings
> first caused a headache the first time this import was attempted and some
> buildings which were of better quality than the import were wiped out.
> 6. split into non-existing and pre-existing buildings. Conflating with
> existing polygons will be more difficult and time consuming. Thus it would
> be good to keep that step in separate changesets with appropriate comments
> so it's easier to review each others work, and disagreements can be more
> easily rectified without touching undisputed work. I've noticed other
> building imports have done this where they split the dataset into
> overlapping and non-overlapping polygons by script.
> 7. be more specific in the instructions about deciding which
> footprints are added. Will they be compared to background imagery?
> Sometimes <http://www.openstreetmap.org/changeset/44545610> buildings
> are completely wrong (mixed up in their dataset). And picking between
> existing and imported data is subjective, thus more detailed instructions
> would be good to improve quality and consistency between users.
> 8. I would also like to see instructions on checking and copying over
> tags in pre-existing buildings which are to be replaced. And discuss how to
> handle offsets. What's the quality of the building survey? Should the
> aerial imagery be aligned to the polygon, or vise versa?
> Talk-ca mailing list
> Talk-ca at openstreetmap.org
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