[Talk-ca] 2020 building import wiki comment by Nate Wessel

John Whelan jwhelan0112 at gmail.com
Fri Jan 18 20:48:21 UTC 2019 

The import mailing list was pointed to the correct page of the wiki.  
The initial post was to say this is what we were thinking of and there 
was a comment saying we needed to change the comment line.

 >There is no mention of this proposed import on the import catalogue


The import process was reviewed by the person who set up the Ottawa 
import did we miss that step on the Ottawa import as well?  Neither was 
it raised as a concern on the import mailing list. I think this is very 
minor and can be corrected.

We learnt a fair bit on the Ottawa import and my expectation is since we 
are using experienced mappers to do the import conflation would be 
either handled by them or the building not imported. We aren't using new 
mappers in a mapathon here and with experienced mappers then I think you 
have to trust them.  The world isn't perfect. Think in terms of service 
level.

 >There are 2X more nodes than needed to represent the building accurately.

The problem with correcting this is you are introducing approximations. 
This will vary according to the source and this can be simplified or 
corrected once its in OSM. I think this is a different issue of a 
mechanical edit that needs to be considered separately.

If we are concerned with database size then I suggest we change the 
instructions to say put the source comment on the change set rather than 
on the building outline.

Cheerio John


Nate Wessel wrote on 2019-01-18 3:06 PM:
>
> 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 <bike756 at gmail.com 
>> <mailto:bike756 at 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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>>>     Talk-ca at openstreetmap.org <mailto:Talk-ca at openstreetmap.org>
>>>     https://lists.openstreetmap.org/listinfo/talk-ca
>>     _______________________________________________
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>>

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