[OSM-talk] The French Corine Import has started
Emilie Laffray
emilie.laffray at gmail.com
Tue Sep 29 11:32:12 BST 2009
2009/9/29 Joseph Reeves <iknowjoseph at gmail.com>
> Hi Emilie,
>
> Apologies for not replying in French - although I have an interest in
> what you're doing, I don't have the language skills to speak to you
> about it natively.
>
> I'm very pleased to see that the Corine data import is going forward
> and am looking forward to seeing the results when it's complete. At my
> place of employment we make some use of OSM (see [1] for example),
> including in France, and we are considering using it to a much greater
> degree in the future. We are having ongoing discussions, however,
> about OSM completeness surveys - in short there are people who want to
> use OSM but want to be able to be explicit about what areas are
> covered and which are not. Which seems fair enough...
>
> I was wondering if the Corine data import could give us such
> statistics for France. Is it possible to say, for examples, how many
> polygons exist that are tagged landuse:residential that don't overlap
> a way tagged highway:residential ? Is this the sort of thing other
> people see value in?
>
> Regards,
>
> Joseph
>
Hello,
don't worry about answering in French. I have been living in English
speaking countries for many many years.
Corine can provide you with some of the statistics that you are asking for.
There are some imprecision about some polygons as you cannot see some
details sometimes, but generally speaking it would be not that difficult to
get some basic statistics. I am doing most of my statistics with postgis
since it is giving me lots of power over what I can do. The most difficult
part is always to give a clear description of what you want. If you are not
careful, you will get meaningless statistics.
There are of course caveats to that due to the way roads are being tagged,
their length, the precision of the polygons, etc... Corine land cover is
only mapping areas more than 25 ha so some towns in my home area are not
appearing as landuse=residential, even if they are clearly in a village. In
addition, data is at least from 2006, maybe older. I will have to tweak
landuse residential polygons around my area to make sure that they match
reality.
Emilie Laffray
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