[Tagging] tagging the multipolygon model (was landuse and military)

Anthony osm at inbox.org
Fri Oct 16 14:26:29 BST 2009

On Fri, Oct 16, 2009 at 5:16 AM, Richard Mann
<richard.mann.westoxford at googlemail.com> wrote:
> Rather than having a bot go round making the data more complicated (and in
> the case of very large lakes with lots of islands, and ponds on those
> islands, it would be very, very complicated), surely it is better to have a
> table available somewhere for people to go look up whether a polygon has
> multiple landuses, which landuse is innermost, and what polygons it's
> inside.

I wouldn't say "surely".  It all depends on your target audience.
Personally, I say the world is complicated, and accuracy trumps
simplicity.  But if that's not the direction OSM decides to go in,
that's fine, it's all under a free content license, after all.

On Fri, Oct 16, 2009 at 6:21 AM, Martin Koppenhoefer
<dieterdreist at gmail.com> wrote:
> 2009/10/15 Anthony <osm at inbox.org>:
>> "School" and "lake" are not landuses though, are they?
> might be, but you'll surely find 2 landuses (as used in OSM) on the same place.

Such land is generally designated as "mixed use", or perhaps "mixed
use X", where X is the primary use of the land.  I suppose in some
situations (apartments over top of retail shops) mapping two landuses
on the same physical area can be appropriate.  But that's much more
rare than what we see in OSM today (it's also a good reason why a
completely automated solution won't work).

I missed your parenthetical of "as used in OSM", though.  "As used in
OSM", currently, is wrong.  It may be good enough for Mapnik and
Osmarender, but I thought we were making data for general use, and not
just for Mapnik and Osmarender.

>> I'm not even sure "forest" is a proper "landuse" tag.  I guess if it's
>> meant to mean "tree farm" (http://en.wikipedia.org/wiki/Tree_farm).
>> But most "forest" areas aren't "tree farms", they're "natural=wood".
> no. Don't know how you handle this in France, but in Germany and Italy
> most forests are landuse=forest and natural=wood is used only in rare
> cases (really and totally unmanaged forests). Read wiki and various
> discussions about this ever actual topic ;-)

Once again, I wasn't referring to de facto use, I was referring to how
the data ought to be organized.  "Forest" is not a land use.  A
"forest" can be used for lots of different things.

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