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" <[email protected]> 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/ > > _______________________________________________ > Imports mailing list > [email protected] > https://lists.openstreetmap.org/listinfo/imports >
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