Ulf Lamping napsal(a): > Am 16.11.2010 13:51, schrieb M∡rtin Koppenhoefer: >> 2010/11/16 Ulf Lamping<ulf.lamp...@googlemail.com>: >> >>> So what is the *exact* problem with surface? >> >> it extents the usage of surface as attribute for routable entities to >> all kind of entities, therefore reducing simplicity for the data >> consumers with no benefit at all. > > No, surface was meant (and is in fact used widely) to describe the > surface material of something, being it a highway, beach or whatever. > There is e.g. *no* problem to describe the surface of e.g. natural=beach > with that tag.
And that's the main problem with using surface tag instead of
specialized landcover.
Currently if I want to simply describe "what's on the ground of certain
area" I should:
1) search for a suitable tag value in landuse (although I have no idea
what the land is used for, I just want the tag to say "here you can see
[that] covering the ground"),
2) search for a suitable tag value in natural,
3) use surface='that'+area='yes'.
I really fail to see the benefit of keeping this mess (and inevitably
extending it with growing number of surface values), both data consumers
and osm editors would imho benefit from introduction of better tagging
scheme for this (e.g. landcover).
Introducing landcover tag and moving some values of other tags under it
would be good for several reasons:
1) Resolving the mess in tagging scheme described above.
2) The meaning of landuse tag could be finally truely limited to
describe the usage of the land.
3) The meaning of surface tag could get back to its original -
describing a property of a certain object.
4) Landcover tagging scheme is more foolproof:
- You can easily check for errors like intersection of areas with
landcover tag.
- User does not need to remember to add area=yes (in contrast with
extended usage of surface tag).
5) Landcover and landuse/natural are orthogonal - e.g. part of your
beach can be covered by pebblestones, another by sand and the sand can
continue to cover the ground outside the beach - now what?
a) You could input the beach as 2 entities instead of one, add one
of them surface=sand, another surface=pebblestone and then add third
area with surface=sand+area=yes.
b) Or you draw one polygon with natural=beach, and then two areas
with landcover tag.
I really think (b) is easier for both data consumers and osm editors.
Petr
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