Hi all,
The wiki page is indeed looking a whole lot better right now - my thanks
and congrats to everyone who contributed! There is a still a ways to go,
but we seem to be getting there quickly.
I'll echo John in saying that I would appreciate hearing from some of
the other people who chimed in to express their doubts about the import.
For my part, I'm not satisfied yet - no surprise, I'm sure ;-). I'm
thrilled that we're talking and working together in the open, and that
addresses the biggest concern I had with the import.
These are the big issues I see remaining:
1. *Validation*: Ideally I'd like to see a good chunk (more than half)
of the data that has been imported already validated by another user
before we proceed with importing more data. Validation is part of the
import plan, so the import isn't done until validation is done anyway.
My hope is that this will flag any issues that we can fix before moving
forward, and give people time to chime in on the import plan who maybe
haven't already. I don't want to see everything imported and only then
do we start systematically checking the quality of our work, if ever. If
no one wants to do it now, no one is going to want to do it later
either, and that doesn't bode well.
2. *Simplification*: James' analysis showed that simplification could
save several hundred megabytes (and probably more) in Ontario alone.
This is totally worth doing, but we have to document the process and be
very careful not to lose valuable data. I believe there was also a
concern raised about orthogonal buildings being not quite orthogonal -
this is something that we should handle at the same time, again, very
carefully. We certainly don't want to coerce every building into right
angles. With respect to James, I'm not sure this is something that can
be done with a few clicks in QGIS. I would be willing to develop a
script to handle this, but it would take me about a week or two to find
the time to do this properly. We would need to simultaneously A)
simplify straight lines B) orthogonalize where possible and C) preserve
topology between connected buildings. This is not impossible, it just
takes time and care to do correctly.
3. *Speed and Size*: To John's point, it seems like people certainly are
not sticking to the areas they know, unless they get around a whole hell
of a lot more than I do, and yes this is a problem. The whole Toronto
region was basically imported by two people: DannyMcD seems to have done
the entire west side of the region (hundreds of square kilometers) while
zzptichka imported the entire east side of the region (again a truly
massive area), both in the matter of a week or two. They only stopped in
the middle where there were more buildings already and things got a bit
more difficult. The middle is where I live, and when I saw that wave of
buildings coming, I sounded the alarms.
This is way too fast - no one person should be able to import the GTA in
a couple weeks. A big part of the problem, IMO is that the task squares
are much too large, and allow/require a user to import huge areas at
once. At the least, some of the task squares in central Toronto are
impossibly large, including hundreds or thousands of buildings already
mapped in OSM. Conflation on these, if done properly would take the
better part of a day, and people are likely to get sloppy.
I would like to see the task squares dramatically reduced in size as a
way of slowing people down, helping them stick to areas they know well,
and keeping them focused on data quality over quantity. This would also
make the process much more accessible to local mappers who don't already
have tons of experience importing.
4. *Conflation*: I don't think the current conflation plan is
adequate(ly documented). In practice, what people are actually doing may
be fine, but I really want to see some better thought on how to handle
existing buildings. Right now the wiki says for example "/Before merging
buildings data switch to OSM layer and see if there are any clusters of
buildings without any meaningful tags you can delete to save time when
merging/."
With respect to whoever wrote this, this approach seems to value time
over data integrity and I just don't think that's how OSM should
operate. We need to be more careful with the existing data, and we need
to show that care with clear and acceptable guidelines for handling the
data that countless people have already spent their time contributing.
We don't do OSM any favours by carelessly deleting and replacing data.
Help convince me that this isn't what's happening.
Until some effort has been made to address these concerns, I will
continue to oppose this import moving forward. And to be clear, I don't
want to oppose this import - I have too much else I should be focusing
on. I just don't want to see another shoddy import in Toronto (or
elsewhere).
Best,
Nate Wessel
Jack of all trades, Master of Geography, PhD candidate in Urban Planning
NateWessel.com <http://natewessel.com>
On 1/26/19 8:49 AM, john whelan wrote:
I'm not certain how this addresses the concerns raised by Andrew
Lester and
Pierre Béland,
and I seem to recall one other person who expressed concerns.
I think it is important that their concerns are addressed.
Perhaps they would be kind enough to comment on whether or not this
approach addresses their concerns.
Do we have a concern that some mappers have been importing buildings
further than say twenty kilometers from where they live?
Have you found volunteers of local mappers in
Alberta
British Columbia
Manitoba
New Brunswick
Newfoundland and Labrador
Northwest Territories
Nova Scotia
Nunavut
Ontario
Prince Edward Island
Quebec
Saskatchewan
Yukon
Who will be willing to oversee the import in each province?
Does this mean the smaller provinces may not see any data?
How will you handle cities of say 80,000 population in a smaller
province who have an interest in seeing their buildings available but
have no idea on how to contact the provincial group?
If we go back to earlier times it was a suggestion in talk-ca that we
use the single import approach and it was mentioned at the time there
didn't seem to be a list of local mapper groups in Canada.
I'm not saying the approach of a single import as far as the import
list and talk-ca followed by a procedure of locally organised mappers
bringing in the data is wrong I'm just trying to ensure the project
moves forward and we are in agreement.
Thanks
Cheerio John
On Sat, 26 Jan 2019 at 00:17, OSM Volunteer stevea
<stevea...@softworkers.com <mailto:stevea...@softworkers.com>> wrote:
Thanks to some good old-fashioned OSM collaboration, both the
https://wiki.osm.org/wiki/Canada_Building_Import and
https://wiki.osm.org/wiki/WikiProject_Canada/Building_Canada_2020#NEWS.2C_January_2019
have been updated. (The latter points to the former).
In short, it says there are now step-by-steps to begin an import
for a particular province, and that as the steps get fine-tuned
(they look good, but might get minor improvements), building a
community of at least one or two mappers in each of the provinces
with data available, the Tasking Manager can and will lift the "On
Hold" or "Stopped" status.
Nice going, Canada!
See you later,
SteveA
California
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