On 7/2/2011 9:00 AM, Jakub wrote:
According to this reation:
http://www.openstreetmap.org/browse/relation/7888 Czech republic (and
many more countres) is not in Europe. Or am I missing something?
I don't see Germany or France either!
I tried to build a geospatial hierarchy out of OSM about a year ago
and gave up on it because the quality of data wasn't good. I ended up
using Yahoo's GeoPlanet because at least it was (sorta) consistent,
even if the shapes look terrible.
For instance, one problem is that there's no constraint that
forces country outlines to be closed. For instance, the boundary of
South Africa contained only the coastline. This kind of problem
persists in OSM because OSM's "quality control" mechanism is feedback
that come from users who are interested in maps. If you're just drawing
maps, the boundaries of the countries to the north of South Africa will
cause the boundary to be properly drawn. Nobody sees or cares that
there's something wrong.
On the other hand, if you're interested in doing spatial reasoning
("Is point A inside South Africa?") the non-closed country boundary is
absolutely useless.
I guess the answer is somebody who wants good data in this
department ought to fix it, but it's a big job, and since GeoPlanet is
"good enough" for now, I haven't been motivated to try to do anything
about it.
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