John,
You seem to be playing the long game with this data - it sounds like
you've been working with this a lot longer than I have, and you've put
in the time and effort to help make this actually-quite-incredible
dataset available to us. I don't want to stop the import from happening
- quite the opposite. I just want to make sure that the time is taken to
do this right. OSM deserves that. Your (our) long awaited victory will
be the sweeter for our patience now.
There are several specific issues I see where the I's are not crossed,
nor the t's dotted. I've mentioned several already, so I'll try to be
brief (I really need to get back to working on my dissertation).
1) There was extremely limited discussion on the imports mailing list.
The initial email did not make clear the scope of the project. I read
the email and did not think twice at it, thinking it was entirely about
Ottawa. The link in that email was actually to the Ottawa import, and
not this one, which seems to have been only in draft at the time.
https://lists.openstreetmap.org/pipermail/imports/2018-November/005812.html
As such, this project has NOT been reviewed by the imports list, which
is a requirement for proceeding with the import.
2) There is no mention of this proposed import on the import catalogue
(https://wiki.openstreetmap.org/wiki/Import/Catalogue)
which is required in the imports guidelines. I suspect many other
guidelines have not been followed.
3) The wiki page describing the import is not adequate to assess the
quality of the data or of the proposed import. See for example:
https://wiki.openstreetmap.org/wiki/WikiProject_Canada/Canada_Stats_Canada_Building_Outlines_Import/Plan#Risks
The import guidelines call for a description of how conflation will be
handled. The fact that two of the major importers seem to have a
substantial disagreement about how to handle existing data indicates
this was not well discussed and I can see that it isn't well documented.
4) The buildings need to be simplified, quite a bit actually. Most
buildings have multiple nodes representing straight lines. This bloats
the database and makes things harder to edit by hand later. There are
probably 2x more nodes than are needed to represent the data accurately,
making it harder for editors and data consumers to work with down the
road.This is a simple fix that will save countless hours later.
... I could go on, but I think this is plenty sufficient to justify
pressing pause on all this.
Again, I don't in any way want to disrespect the work that has gone into
this effort already. We're all volunteers here and I know how much time
this all takes. However. importing all/most of the buildings in Canada
is a monstrously large task, which will have to dance around a lot of
people's toes. We should expect this to take a really damn long time if
we're going to do it right. We need to have the patience to learn from
experience, from critique, and from the wisdom of the people who've
learned from flawed imports in the past and have devised guidelines and
processes so that we can have better experiences with this in the future.
Nate Wessel
Jack of all trades, Master of Geography, PhD candidate in Urban Planning
NateWessel.com <http://natewessel.com>
On 1/18/19 2:24 PM, john whelan wrote:
My background is I'm a retired civil servant who has written and
overseen procurement documents and fairly large procurements. Dotting
the is and crossing the Ts are my speciality.
There are two parts to an import. The first part is the part played
by the import mailing group. They confine themselves to is the
license correct and do you have a reasonable plan. In this case the
license is one of the few that has been confirmed by the Legal Working
Group of OpenStreetMap and as such no questions were raised about it
on the import mailing list. We have methodology that has been used
before successfully with the Ottawa building outline import. There
were major discussions both on talk-ca and the import mailing group
before that import took place and we took note of the issues raised
and addressed them. The licensing issue goes back about eight years
to when I was talking to Federal Government Treasury Board and
explaining their Open Data license did not align with OSM. That is
why their license is now known as 2.0.
The second part is the local group makes the decision to import they
are the authority no one else.
Apparently you were not part of the talk-ca when the discussions took
place which would have been the time and place to raise concerns.
When the Ottawa import was done there were one or two places where the
existing buildings and the import overlapped. In the instructions on
the import there are instructions to cover this. Specifically there is
a validation step. I seem to recall the error rate was of the order
of 1% and I expect this latest batch to be roughly the same.
If you can identify which municipalities data is of poor quality then
I'm sure we can remove these. For the most part these are from the
foundation plans recorded by the municipality using professional
surveying techniques.
Would you like to clarify exactly where I failed to dot the Is and
cross the Ts please.
Many Thanks
John
On Fri, 18 Jan 2019 at 13:37, Nate Wessel <bike...@gmail.com
<mailto:bike...@gmail.com>> wrote:
Hi John,
As Steve has said, you seem to be the only one suggesting that
thousands of import committees might need to be formed. Certainly
I'm not suggesting that.
My understanding of OSM import procedure (and wiki-style projects
more generally) is that imports should operate in an essentially
consensual way where possible. The goal is to build consent and
bring people on board with a project or a change by addressing
their concerns in a meaningful and respectful way.
I think that I have made some substantive and troubling claims
about the quality of the data being imported. I've pointed out
that this project has not followed the import procedures that were
produced by a community of mappers larger than just those in Canada.
So to respond to your implication, I am in some sense the one
reviewing the project, just as I would welcome you to find ways
that my own contributions could be better. If you want my
credentials for reviewing your work, here they are:
1) I am an active contributor to OSM in Toronto, where I live (and
elsewhere)
2) I am currently helping to lead a building import in Hamilton
County Ohio that has better addressed some of the issues I see
this import struggling with. I can help you do the same.
3) I've been doing research in GIS for a long time now, though I
don't need that to tell you that the issues I've described are
hardly insurmountable technically or even all that difficult to
fix. It would take maybe one day's hard work to get the technical
side of this right.
I think Canadian OSMers will agree that we can take a pause to get
things right on such a massive import. If they don't - if I'm
shouted down or better, if my critiques are adequately addressed,
then I will leave you to finish the project in peace. I might even
lend a hand if all goes well, as I sincerely hope it does :-)
Best,
Nate Wessel
Jack of all trades, Master of Geography, PhD candidate in Urban
Planning
NateWessel.com <http://natewessel.com>
On 1/18/19 1:11 PM, john whelan wrote:
I know of no other way to contact him but he made an interesting
comment that the project is on hold in the wiki pending review.
Would he care to comment on who is supposed to be reviewing the
project?
My understanding is that the import was raised in talk-ca before
it commenced for comment and these were generally favourable. I
took that as the local mappers to Canada had been consulted and
they are the "local mappers" authority in this case.
I understand he has concerns about local mappers making decisions
but in Canada we have been importing similar data through CANVEC
for some time. CANVEC data comes from a number of sources
including municipal data.
Is he suggesting that each of the 3,700 municipalities in Canada
should form a group of local mappers who can make individual
decisions on whether their municipal data should be imported and
we should end up with 3,700 import plans?
Thanks John
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