[Talk-ca] Some feedback on import quality in Toronto

[Nate Wessel]

John,

You seem to be mostly addressing topics which have been brought up 
elsewhere. My email was meant to address specific data quality issues in 
Toronto, so I'm not sure how to respond to all of this.

To your broader question though, my position is that we *do* have the 
volunteers and skills necessary to make this a good import. Supposing 
that we didn't though, then I would have to say that the import should 
wait until we have the right people working on it. A bad import is worse 
than no import.

Cheers,

Nate Wessel
Jack of all trades, Master of Geography, PhD candidate in Urban Planning
NateWessel.com <http://natewessel.com>

On 2/3/19 1:14 PM, john whelan wrote:
> My expectation was that the import would be based on the city's 
> records of foundations for the buildings.
>
> I would not expect to see sheds etc.and I'd be quite happy to only get 
> most of the buildings. The rest can be added by local mappers at a 
> later date.
>
> My expectation is they will be consistent and not some mapped from 
> Bing, others from ESRI etc.
>
> There are estimated to be in excess of 11,000,000 buildings in 
> Canada.  I don't think we have enough skilled mappers to map them all 
> from imagery.
>
> My expectation is the import would give us a reasonable number of 
> fairly accurate building outlines at relatively low cost in mapper 
> time.  Missing building imports from city open data are now fairly 
> common in many parts of the world.
>
> My expectation is that the building outlines would have additional 
> tags added and that this would draw in less skilled mappers.  At the 
> same time corrections could be made to the outlines if deemed necessary.
>
> It would avoid too many badly mapped buildings.
>
> Before the import started it was raised in talk-ca and there was some 
> discussion.  I understand you were not a member at that time or took 
> part in that discussion but that doesn't change the fact that the 
> issue was discussed.
>
> The idea of a single import plan came from talk-ca and that is why 
> there is a single import plan covering the entire country and there 
> was discussion on talk-ca on the point.
>
> The original plan on the wiki mentioned having some coordination in an 
> area.  I don't think this happened but it was an attempt to give a 
> louder local voice as it was recognised it would be better if local 
> mappers took the lead.
>
> Different mappers have different ideas of what is acceptable.  I think 
> your standards are fairly high thus more demanding in resources and do 
> we have enough resources?  I don't think we do to import to the 
> standard at which you are asking.
>
> Could you clarify what you are saying?
>
> I assume that for other parts of the country if they wish to continue 
> and find the building outlines acceptable they may do so?
>
> Thanks John
>
> Thanks John
>
>
>
> On Sun, 3 Feb 2019 at 12:34, Nate Wessel <bike756 at gmail.com 
> <mailto:bike756 at gmail.com>> wrote:
>
>     Hi all,
>
>     I had a chance this morning to work on cleaning up some of the
>     already-imported data in Toronto. I wanted to be a little
>     methodical about this, so I picked a single typical block near
>     where I live. All the building data on this block came from the
>     import and I did everything in one changeset:
>     https://www.openstreetmap.org/changeset/66881357
>
>     What I found was that:
>
>     1) Every single building needed squaring
>
>     2) Most buildings needed at least some simplification.
>
>     3) 42 buildings were missing.
>
>     I knew going in that the first two would be an issue, but what
>     really surprised me was just how many sheds had not been imported.
>     There are only 53 houses on the block, but 42
>     sheds/garages/outbuildings, some of them quite large, and none of
>     which had been mapped.
>
>     I haven't seen the quality of the outbuildings in the source data,
>     and maybe I would change my mind if I did, but I think if we're
>     going to do this import properly, we're going to have to bring in
>     the other half of the data. I had seen in the original import
>     instructions that small buildings were being excluded - was there
>     a reason for this?
>
>     I also want to say: given how long it took me to clean up and
>     properly remap this one block, I'll say again that the size of the
>     import tasks is way, way, way too large. There is absolutely no
>     way that someone could have carefully looked at and verified this
>     data as it was going in. I just spent a half hour fixing up
>     probably about one-hundredth of a task square.
>
>     We can do better than this!
>
>     -- 
>     Nate Wessel
>     Jack of all trades, Master of Geography, PhD candidate in Urban
>     Planning
>     NateWessel.com <http://natewessel.com>
>
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