[Talk-ca] Building Import update

Sat Jan 26 16:14:51 UTC 2019

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 
> <steveaOSM at softworkers.com <mailto:steveaOSM at 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
>     _______________________________________________
>     Talk-ca mailing list
>     Talk-ca at openstreetmap.org <mailto:Talk-ca at openstreetmap.org>
>     https://lists.openstreetmap.org/listinfo/talk-ca
>
>
> _______________________________________________
> Talk-ca mailing list
> Talk-ca at openstreetmap.org
> https://lists.openstreetmap.org/listinfo/talk-ca
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstreetmap.org/pipermail/talk-ca/attachments/20190126/f1b43508/attachment.html>