[Talk-GB] "Lines of Trees" along river banks etc.

OpenStreetmap HADW osmhadw at gmail.com
Fri Aug 30 11:04:24 UTC 2013


On 29 August 2013 09:42, sk53.osm <sk53.osm at gmail.com> wrote:

> comparable to the European Environment Agency's Urban Atlas. The slides are
> here. I think there are enough details in the methodology for anyone to

You might have warned me about the size of the document, so I
downloaded it at off peak times!

Unfortunately there seem to be a lot of professional references, which
probably won't make sense to me without further research.  However, my
take on problems with landuse is that they arise from amateur mappers.

>
> Whereas there are some issues with landuse tags, they will not be fixed by
> inventing another category which will be beset by the same problems over
> time. It's much better to try and persuade people that things like
> landuse=grass for farmland pasture is a bad idea.

In particular, this is like the presentational/semantic debate in
HTML.  Landuse is a semantic concept, but amateur mappers tend to
think in presentational terms, and because landuse=forest was the only
way of representing trees, in the rendered Mapnik rendered image, they
coded the central reservation as a forest.  landcover would be a more
presentational coding, and would allow people to achieve the rendering
they wanted without distorting the deep meaning of the data.

The whole history of HTML has shown that when you give the technology
to the masses, you will end up with presentational markup, so, if you
don't provide an alternative way of getting the rendering, you can
expect landuse to be abused for that, and even if you do, a lot of
people will fail to understand the difference.

(natural also has problems.  There is an area near me currently coded
as natural=trees, but, which on further research turns out to actually
have been landscaped.  Mapnik renders this as solid green, without
tree texturing, so this was not an attempt to control presentation.  A
less sophisticated user would probably coded it as a forest, to get
the texturing, when it is really part of a park.)



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