[OSM-talk] Import guidelines proposal update

[Vincent de Chateau-Thierry]

> De : "Lester Caine" 
>
> So would it not be better to provide it as an raster overlay instead? And trace 
> from that.
> 
> But I was assuming that this was vector data? 

French cadastre is vector data in about 70-80% of the 36.000 municipalities. The rest is
made of old paper maps turned into pixels and delivered as raster data. Both are
available as raster layer in JOSM thanks to the cadastre-fr plugin.

For the vector data, it is also available as raw .osm files, split into thematic layers :
mainly administrative boundaries and buildings.

So it can be processed into a 
> database? I am sure that from version to version they are not going to be 
> changing the coordinates of the majority of buildings? All that raw data can be 
> imported as a layer in OSM, but in addition it can be compared with a previous 
> import and identical elements ignored? That just leaves the changes between 
> versions to be processed, and you end up with a better version of the cadastre 
> data than the government ;) And reference it to the rest of the OSM data.

Sure it can be processed. Change detection for buildings is a topic discussed on talk-fr
but there is no real tool vailable yet to deal with it. And as said by Jean-Marc,
buildings taken from the cadastre as vector parts don't have any ID at all. 

vincent


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