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

Ben Laenen benlaenen at gmail.com
Fri Oct 16 15:34:49 BST 2009


Anthony wrote:
> Maybe we need "ground cover".  I'm not convinced of it, but maybe we
> do.

Well, all topographical maps I've seen seem to be convinced of ground cover.

This is ground cover for example:
http://www.ngi.be/Templates/zoom.htm?doctitle=uittreksel&image=../images/1/1/extr10_vismijn.jpg&x=452&y=452
http://www.ngi.be/Templates/zoom.htm?doctitle=uittreksel&image=../images/1/1/extr10_duinen.jpg&x=452&y=452

There are extra captions like "Camping", "Golf course", "Park" etc for some 
land uses.


> But this is a completely different problem - it's the opposite
> problem of landuse=*, in fact.  Instead of using one tag for multiple
> things, we're using lots of tags (amenity=*, man_made=*, natural=*,
> leisure=*) for what you're arguing to be one thing (as I said, I'm not
> yet convinced).

No, we're using all those tags for two things, both land use and ground cover. 
And often it's not clear which one.

There are no rules to translate ground cover to landuse or the other way 
around. An area with grass can be in a residential area, in a nature reserve, 
in a farm, or in a military domain, or in a nature reserve which is part of a 
military domain. And on the other hand for example a farm could be grass, crop 
fields, stables, orchards, green houses...

Land use doesn't tell anything about ground cover, ground cover tells nothing 
about land use. Sure, some ground covers wouldn't make much sense in a certain 
land use and vice versa, but that doesn't make that sentence less true.

Hence we need both of the concepts, but certainly not in the mixed and unclear 
way which is currently the case in OSM and is confusing many mappers.

Ben




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