[Imports] Ongoing Canadian building import needs to be stopped, possibly reverted

John Whelan jwhelan0112 at gmail.com
Thu Jan 17 17:05:49 UTC 2019

I'll contact you directly off list to address your concerns.

Thanks John

Nate Wessel wrote on 2019-01-17 10:28 AM:
> I just learned yesterday of a very large import of buildings across 
> Canada that seems to have been posted to this list in November without 
> getting much of a response. I remember seeing the email about it at 
> the time, and as there was substantial reference to an import in 
> Ottawa, I thought the import was limited to that city and failed to 
> read the actual details of the proposal. This appears to be an import 
> of building footprints across ALL MAJOR CANADIAN CITIES.
> https://wiki.openstreetmap.org/wiki/WikiProject_Canada/Canada_Stats_Canada_Building_Outlines_Import/Plan
> https://lists.openstreetmap.org/pipermail/imports/2018-November/005812.html
> This is being imported NOW, very quickly, and the data I've seen in 
> Toronto is of dubious quality at best. Given the speed with which this 
> has taken place and the lack of clear discussion about what exactly 
> the import is, what exactly it covers, I would like to see this import 
> effort halted immediately if not reverted.
> My concerns are as follows:
> 1. I'm a very active mapper living and editing in Toronto and 
> subscribed to the relevant lists and slack channels, yet I only just 
> learned of this when the buildings encroached on my own neighborhood. 
> I imagine many others also missed the notice and have not had any 
> chance to review the plan.
> 2. There are countless examples of truly terrible data quality, weird 
> footprints, overlapping buildings, wildly unsimplified geometries, 
> etc. e.g.
> https://www.openstreetmap.org/way/663824488
> https://www.openstreetmap.org/way/662764169
> etc.
> These issues clearly fail in a simple JOSM validation, which indicated 
> that no validation is happening before upload.
> 3. The data is being imported in extremely large chunks, (see the 
> tasking manager grid for Ontario: 
> http://tasks.osmcanada.ca/project/145), much larger I think than any 
> one person could validate or review in a single sitting. There are 
> more than ten thousand buildings in some of these grid cells. As 
> changesets are limited to 10k objects, including nodes, it is 
> extremely difficult to see what data was there before these changes, 
> as each task involves multiple essentially simultaneous changesets.
> 4. The approach seems to be import first, validate second (if ever?).
> 5. The wiki plan gives no clear description of the plan for 
> integrating new data with old. In places where there used to be 
> user-contributed buildings, I now see buildings from this import 
> covering or replacing those buildings with no remaining way history. I 
> don't think I need to say that this is completely unacceptable.
> What are the options on the table here? There has been a truly massive 
> amount of data imported in the last couple of weeks. I'd love to wind 
> back time and criticize the living hell out of this plan before it 
> started, but that's not where we're at. What can be done?
> :-(
> -- 
> Nate Wessel
> Jack of all trades, Master of Geography, PhD candidate in Urban Planning
> NateWessel.com <http://natewessel.com>
> _______________________________________________
> Imports mailing list
> Imports at openstreetmap.org
> https://lists.openstreetmap.org/listinfo/imports

Sent from Postbox 
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstreetmap.org/pipermail/imports/attachments/20190117/ae9ca22b/attachment.html>

More information about the Imports mailing list