[OSM-talk] Parking symbols: YUCK!

[David Earl]

On 24/02/2008 10:53, J.D. Schmidt wrote:
> So IMHO it's up to the rendering engines to render the data smartly. 
> It's not the rendering engines that decide what should be put into the DB.

I'm on both sides here: I agree that it would be better not to have both 
a node and an area; OTOH, there's already lots and lots of these, so it 
is shooting ourselves in the foot not to clear up the mess in one way or 
another.

And I'm confused about what Mapnik is actually doing to get this right 
(if indeed it is always getting it right).

There's two ways to do it: either

(1) we pass over the data (ideally automatically) and check for parking 
node within parking polygon, delete the node (or maybe just change its 
tag, to say parking:redundant, so we don't lose anything accidentally), 
and transfer any name tag to the area, providing there is no clash,. 
i.e. the area doesn't already have a (different) name

or

(2) we change osmrender so it only puts the icon in when there isn't 
already a relevant node. This would require osmarender to (a) maintain 
some state: keep a list of parking nodes or areas, and (b) to do the 
artificial icon after all the nodes (in the layer presumably). Can XSLT 
do this?

In both cases, I think a bounding box test would be sufficient rather 
than a general point in polygon test, but that's a pretty minor detail.

(2) has the advantage that the mapper can override a naive rendering 
algorithm, and copes with the existing data, but I suspect not knowing 
much about XSLT that this would be rather hard to do, but it does mean 
the existing "bad practice" (in quotes because not everyone is of that 
opinion) is propagated.

David