[OSM-talk] All you've ever wanted to know about the french cadastre

[Lester Caine]

Martin Koppenhoefer wrote:
>> We provided explanations many times...
>> >Separate polygons can come from:
>> >- different ownership of building parts
> ...
>> >It is not data errors, but much more detailed geometry compared to
>> >what you can do by simply surveying or trace on aerials.
>
> IMHO it is a data error when one building is split up into several
> buildings because the one building has more than 1 owner, or do you
> tag the parts as parts and have eventually a method of recombining
> these parts into one building? As far as I know we do not at all tag
> owners of objects in OSM.

I'm happy to split buildings where I have house numbers ... then there is an 
identifiable difference between the two halves. But I am sorry Christian I 
simply do not accept that cadastre is producing the detail you claim. NONE of 
the buildings that I DID waste time tracking back through the Main site were 
identifiable as separate structures !!! And the facts in the database do not 
support your claim :( The area identified a couple of days back had small 
buildings with multiple odd shaped blocks that bare no relation to the imagery 
and have no additional tagging. It would be easier for a french speaker to get 
back through the Cadastre site, but when I did manage to get to that area I 
could see little to identify separate buildings that were being displayed in 
OSM! Heck, the OS streetview data is cleaner and we decided NOT to import that ...
I have no doubt SOME French mappers are using the data as intended, but on the 
whole I don't think the data does anything to improve OSM :(

-- 
Lester Caine - G8HFL
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