[Imports] Help us address issues with the NYC Import

Jason Remillard remillard.jason at gmail.com
Tue Oct 15 01:35:31 UTC 2013


Problems 1, 2, 3, 4, 6, and 9 should have been fixed before the first
file was uploaded. OSM files that are going to be imported, should
100% clean in the JOSM validator. This is a pretty basic thing, right?

7 - Building that already exist in OSM should be skipped, especially
since it looks like the addresses are going to just stay as isolated
nodes. ST_Intersects is your friend.

9 - Building that overlap with the roads should be pulled from the
rest of the data and conflated separately. In MA, when a building
overlaps a road, most of the time, the road is in the wrong spot, not
the building. It needs a human to sort it out. Use ST_Intersects to
find them ahead of time, and fix the bad roads and import the
corrected buildings by hand.

8 - Any workflow that requires cutting pasting between layers of
multipologons is broken. It is very very tricky to not screw it up,
with 20 people helping, it is hopeless. Please, change your workflow
to not need a copy/paste.


On Mon, Oct 14, 2013 at 5:54 PM, Alex Barth <alex at mapbox.com> wrote:
> Ok, here's what I think we should do:
> 1. Join T intersections in conversion (Matt and I are on this)
> https://github.com/osmlab/nycbuildings/issues/8
> 2. Set up a QA script reporting common mistakes (start here
> https://github.com/osmlab/nycbuildings/issues/18)
> 3. Write up nice blog post highlighting some of the mistakes, send out to
> existing importers
> 4. Reach out personally to repeat "offenders"
> 5. Not grow number of individuals involved until we increase quality.
> On Mon, Oct 14, 2013 at 4:59 PM, Pieren <pieren3 at gmail.com> wrote:
>> On Mon, Oct 14, 2013 at 9:51 PM, Serge Wroclawski <emacsen at gmail.com>
>> wrote:
>> > Yet, despite all this instruction, we had a lot of errors in the data,
>> > even from extremely experienced mappers.
>> > We could really use your help in coming up with solutions to these
>> > problems!
>> We have the same issues in the French building imports since ... 2010
>> (it's a long-running country-wide import). What you can do is
>> - you only allow the import to certified contributors ... or:
>> - provide the best original data. If you can, fix the geometric errors
>> automatically (duplicate nodes, missing intersecting nodes and
>> overlaps). Conflation is a bit more complicate (too many cases) and
>> should remain manual.
>> - contact people and explain them again where they do mistakes and how
>> to proceed (or point again to your tutorials)
>> - create a QA tool reporting the errors you mention then let the
>> community fix them. In France, we developed a QA tool called osmose
>> reporting duplicate nodes, highways crossing buildings (item 1070),
>> buildings overlapping (item 0) etc ([1]). If errors are increasing,
>> create taskforces around a specific error or area.
>> Pieren
>> [1] http://wiki.openstreetmap.org/wiki/Osmose
>> [2] http://wiki.openstreetmap.org/wiki/Osmose/errors
>> [3 http://osmose.openstreetmap.fr/en/map/
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