[Imports] Hungarian CLC import

[Balázs Szalkai]

"I think the question about tagging was refering to how you translate
the Corine-tags to OSM-tags, and which tags from Corine you translate
and which you drop."

Let me put it this way. Some guy in the past has already converted the CLC
dataset to .osm. I don't have the smallest clue who did it and how. Now I
and the other importers are uploading this file in small pieces.

"this is surprising news, really, CLC is more accurate in your area
than what is in OSM?"

Welcome to Eastern Europe! The huge majority of landuse data in Hungary
comes from CLC. At most parts, where no data from CLC has been imported,
there are no landuse polygons. See
http://www.openstreetmap.org/?lat=46.848&lon=18.51&zoom=10&layers=M. If we
did not use CLC, there would be almost NO landuse data at all. I do also
have concerns with the dataset. But currently it is the best we can do.

"You shouldn't really do this, as it is mostly considered bad practise
or even vandalism, as you are deleting the history of these objects."

OK, I wanted to mean those forests which has been imported from CLC some
time ago but without the neighboring farm, vineyard, etc. areas.

"so when in doubt I agree it is better to keep what is
already there in OSM."

I was saying the same. I merely tagged these as "fixme=...". Anyway, Bing
is very outdated in Hungary. Images are about 10 years old and low
resolution at some places.

"If you traced these features by hand from aerial
imagery, would you do it in the way CLC did?"

I would do better, but then please look at this area:
http://www.openstreetmap.org/?lat=47.8738&lon=19.4649&zoom=13&layers=M
There is no high resolution Bing imagery here. Now our only realistic
choice to add landuse data about this place to OSM is to use CLC.

"It
further seems all polygons are overlapping and there are no
multipolygon-relations at all?"

Thanks for pointing that out! I must tell I'm surprised of how this guy
imported CLC data -- it was not me at that area. I'm using proper
relations. I will probably write him about this.

You are right anyway that the polygons need further alignment and
simplification. It needs some work to improve the accuracy of the imported
CLC data. But I believe in an incremental mapping process. For hikers,
hunters, etc. these small misalignments do not mean any problem. Rather, it
presents extra information on landuse which may be off by say 10m, but will
be continuously improved in the future. Once the data is out on OSM, other
contributors will be able to correct errors and improve map quality.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstreetmap.org/pipermail/imports/attachments/20121029/d79bb40a/attachment.html>