[OSM-talk] Parking aisle as boundary of car park not showing
osm.list at randomjunk.co.uk
Thu Sep 25 13:52:27 BST 2008
On Thu, Sep 25, 2008 at 1:22 PM, 80n <80n80n at gmail.com> wrote:
> On Thu, Sep 25, 2008 at 12:53 PM, Dave Stubbs <osm.list at randomjunk.co.uk>
>> 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.
> You're proposing that a field with a hedge around it should be tagged as two
> separate ways that share the same set of nodes right?
> A single object tagged with landuse=field, border=hedge seems pretty
> reasonable and intuitive to me. Where's the madness in this?
Sounds pretty sensible to me too.
Border implies it's a property of the field, and you don't normally
use hedges for anything else.
If we get really super accurate you /might/ find someone mapping hedge
areas, and wondering whether you mapped the centre line or not, but I
Here's another: military=airfield, border=fence, fence_height=3,
Where's the fence/road?
> In this case a renderer might choose to render the field as an area or the
> border as a line or, indeed, both.
> Sometimes it can be the renderer that needs to decide whether something is
> rendered as an area or a line or even a point. A roundabout being a good
> example where at some low zoom level it could be an icon, at another it's a
> filled in blob (an area), and at a high zoom level its a road with a hole in
> the middle.
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