[Imports] [Talk-ca] [Import] Ottawa Buildings & Addresses [Statistics Canada project]
james2432 at gmail.com
Wed Oct 19 23:41:04 UTC 2016
If you really need source data it will be available when the goverment
makes up their mind where to host it. If you need it we have it in GeoJSON
Original file shouldn't matter anyways as it's full of errors to begin with.
As for addresses we have used a set of internal tools(available on github)
to rename and de-retard the original shape file like:
I also have a .net application at work that can do the same processing.
When we were doing the import (was 96% complete before being reverted) at
no point did I see any address that couldn't be determined with the help of
Bing and Mapbox satelite imagery combined. This is why we are working with
experienced users, not mappers that started yesterday. This is why we have
it under risks with a mitigation:
The advantage of working with the local mappers is that if they need a
survey to fix data before import.
Building geometry is compared to properly offset Bing or Mapbox imagery,
which can be aligned using the building data as it is properly aligned and
traced from 30cm imagery dead overhead and not at a 5-20 degree incline
like a lot of satellite imagery.
This is not a pump and dump operation. Every tile tasked via the tasking
manager will be corrected of 1. Errors (JOSM Validator) 2. Addresses will
be properly set overhead of building(buildings that might need terracing)
or merged (single buildings and simpler terracing). *IN NO WAY SHAPE OR
FORM IS THIS A AUTOMATED IMPORT*. It is more like a HOT task, using data
available to us. Errors will be corrected before upload to OSM and before
marking a tile as "done" or "validated"
On Wed, Oct 19, 2016 at 7:01 PM, Christoph Hormann <chris_hormann at gmx.de>
> On Wednesday 19 October 2016, James wrote:
> > Ok, Christoph now that I am at a proper computer I can address your
> > comments:
> > [...]
> Thanks for the additional information. Based on this i modify my
> comments, what i am still missing is:
> - link to the source data for the buildings
> - information on attribute and geometry processing - this refers to how
> the source data is processed to generate the OSM files. Based on the
> address data this is clearly non-trivial and needs further explanation
> (expansion of abbreviations, conversion of upper case names).
> - information on what you actually intend to import - please forgive me
> for not taking the time to scrape every data tile from
> data.osmcanada.ca to determine the extent of the data.
> Additional notes:
> - the address data is clearly not ready for import in the current form,
> it contains lots of duplicate addresses and positions seem pretty far
> off in some cases, often too far to be properly matched with buildings
> without on-the-ground inspection.
> - the building geometries contain various flaws like poor
> orthogonalization, overlaps and impossible geometries like here:
> and systematic errors like here:
> - it is unclear how you intend to determine which building geometry is
> more accurate if there is already data in OSM.
> > If you are just going to skim over documentation, what is the point
> > of creating it?
> The purpose is to document the import to allow mappers to look up how
> this particular import is done. If finding out a specific detail about
> it - like for example to determine how the value of a certain tag is
> determined or which area exactly is affected by the import - requires
> you to read the full text from top to bottom, it does not fulfill this
> purpose that well.
> Christoph Hormann
> Imports mailing list
> Imports at openstreetmap.org
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