[OSM-talk] Parking aisle as boundary of car park not showing

[Dave Stubbs]

On Thu, Sep 25, 2008 at 11:47 AM, 80n <80n80n at gmail.com> wrote:
> This is an interesting topic which is well worth discussion, but to return
> to the original question for a moment.  The issue is that mapnik is not
> capable of rendering a way that is both a path and an area.  The example
> given was highway=service, amenity=parking.
>
> Regardless of whether people are centerlineists or not, there are always
> going to be mappers who will tag ways this way.  We have a free form tagging
> scheme so we cannot prohibit such things.  For example, a way tagged as
> highway=waterway, power=line (two linear tags) might be unusual (water and
> electricity generally don't mix ;) but we cannot disallow it.

Umm... I don't like that argument.

Saying we have a free form tagging scheme, and saying all the
renderers should just cope with absolutely anything someone happens to
have done are two very different things.
We may not be able to "disallow" something, but we can sure as hell
disagree with it and refuse to support it in a particular tool.

Just because everything is "allowed" does not mean there is no such
thing as "wrong" either, it just means our mechanisms for coping with
it are different.


>
> So, if a way is tagged as highway=service to describe a road, but also
> amenity=parking to indicate that the road *"is part of the car park and
> defines its boundaries"* then that's the way it is.
>
> Suggesting that the data be changed to accommodate the deficiency of a
> particular renderer is very much a case of mapping for the renderer.  This
> is a principle that is important to uphold.  Fix the renderer not the data.


And this is the point -- it's not a deficiency... as far as I'm
concerned the car park has been incorrectly modelled. There is no
sense in tagging a feature as both a line and an area... that way
madness lies. And tagging a way/area with more than one feature can be
just confusing. One feature per object is an entirely sensible rule
that people are of course free to ignore... just don't expect anything
to ever work if people make a regular habit out of it. The problem is
that all sense of predictability has just been thrown out... does this
represent a road around a car park, a road in a car park, an area of
service road you can park on, or a centre line of a service road you
can park on?

Dave