[Imports] [Talk-ca] [Import] Ottawa Buildings & Addresses [Statistics Canada project]

James james2432 at gmail.com
Tue Oct 25 12:52:26 UTC 2016


There is also a factual basis in the example Scruss provided:
https://wiki.openstreetmap.org/wiki/File:12.PNG

TD Place(Renovated/New buildings constructed in Summer 2014) is not mapped
in the DWG(scruss said as far back as 2011)
In the newer data it is:
https://wiki.openstreetmap.org/wiki/File:13.PNG

I know this as I am a local mapper.

On Mon, Oct 24, 2016 at 6:52 PM, James <james2432 at gmail.com> wrote:

> I can guarantee that this data is roof level data. While I was examining
> data there were cart returns mapped as outlines. This data was also traced
> via orthophotos
>
> On Oct 24, 2016 6:45 PM, "Christoph Hormann" <chris_hormann at gmx.de> wrote:
>
>> On Monday 24 October 2016, Stewart C. Russell wrote:
>> >
>> > > Could you please clarify what the alleged source of the building
>> > > data to be imported is?
>> >
>> > Yes, as far as I understand it, at least: these data to be imported
>> > were given to a group of OSM contributors by the City of Ottawa. They
>> > have explicit permission to include it in OSM from the City. The only
>> > place you can inspect the data is on the contributors' own hosting
>> > sites, as the city doesn't host it anywhere. Details of the licence
>> > and permissions are on the Ottawa import information page.
>>
>> I would then suggest to contact the person who provided the files for
>> metadata and specifications on those, in particular dates and methods
>> of survey, processing applied, especially coordinate system conversions
>> and specifications on what exactly is contained in it (i.e. what the
>> definition of a building is here and if it's ground footprints or roof
>> outlines).  You also might want to specifically ask regarding the
>> geometry issues i pointed out earlier.
>>
>> You can be pretty sure the original producer of this data set has this
>> information and if there is interest in having this data in OSM they
>> should also be willing to provide such information.
>>
>> In OpenStreetMap we put high importance on knowing and documenting how
>> data is acquired since - as every experienced mapper knows - sources of
>> information can be faulty and misleading.  Just because someone says: I
>> have this data here and you may use it and it mostly looks reasonable
>> and plausible at the first glance does not mean we should throw all our
>> sense for critical evaluation of sources out of the window, especially
>> if you plan to add several hundred thousand new features.
>>
>> > The public 2011 data set is cut into 2×1 km tiles, slicing through
>> > buildings on the border. There are no common attributes which would
>> > allow repair, as the data is packaged in AutoCAD DWG files.
>>
>> This alone should not be a problem since you know the location of the
>> cuts and therefore could dissolve them based on position.
>>
>> The real question is - is there a factual basis for the assumption that
>> the data you intend to import is newer than the data in these files?
>> Note a different level of detail is not necessarily an indication for
>> age or accuracy of the data.
>>
>>
>> --
>> Christoph Hormann
>> http://www.imagico.de/
>>
>> _______________________________________________
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>>
>


-- 
外に遊びに行こう!
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