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

Sarah Hoffmann lonvia at denofr.de
Thu Sep 27 19:18:56 BST 2012


On Thu, Sep 27, 2012 at 04:59:27PM +0100, THEVENON Julien wrote:
> For major part of French contributors we are adding buildings and other details not related to cadastre, so having one account per kind of edit will be really painfull.. but it it will not be for people that just perform raw building imports !

I don't know which data you have been looking at, but let's ask
Nominatim, shall we?

For France we have:
          raw buildings indexed        27337552
          other objects indexed         3799339
-----------------------------------------------
Total number of objects indexed        31136891

Objects are real word objects here: highways, pois, boundaries etc.
In other words, for 7 imported buildings you manage to map one 
non-cadastre object. So indeed, I would agree that French
contributors do map other details. 
Occasionally. Very. Occasionally.

[referring to separate import accounts]
> This is the real problem for us.

For the sake of completeness: planetwide there are currently
152 million objects. Which means 1/6th of the planet consists of
French buildings. Now, there is a real problem.

Whatever use all those balconies, patios and swimming pools might
have in the future, right now in the present the cadastre import
has become a major nuissance for anybody who wants to use OSM data.
It wastes lots of bandwidth and CPU time. If it wasn't for the
cadastre imports, we'd still be able to keep the 32bit id space
for nodes for another year or two, which would save a lot of hard
disk space for a lot of people.

Just some food for thought. Now please don't let me stop you from
continuing to complain about how all those import rules make your 
life so much harder.

Sarah



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