[Tilesathome] RFC: Symbols rendering

[Knut Arne Bjørndal]

On Fri, Sep 12, 2008 at 01:17:10PM +0200, Jiri Klement wrote:
> Hi,
> 
> I've been thinking about how to improve rendering of area with icons
> in osmarender. Currently there is no way how to specify where icon
> should be placed.
> 
> Two things can be implemented:
> 
> 1) Support label relation -
> http://wiki.openstreetmap.org/index.php/Relations/Proposed/Label

+1, great idea. Should be trivial to insert it into the areaCenter
wrapper template (see more later).

> 2) Draw icon in area center only when there is no node inside of area
> with the same tags.

I wouldn't bother about this, I've mostly seen this where you have a
parking space that's input twice, as both area and node. That was
basically a renderer workaround for before the renderers did symbols
for areas.

If we want to do anything about these nodes at all I'd rather convert
them into labels using the relation, thus actually fixing the data
instead of adding a workaround to handle an old workaround.

> The algorithm should work like this:

Why not just put something like this in areaCenterWrapper?
if way is member of label relation with role object
    return label member of relation
else
    <current logic>

> Checking whether point is inside of polygon is quite simple, it should
> be possible to do in xslt in reasonable time. Anyway I'm planing to
> extend area-center preprocessor help osmarender with it.

Point-in-polygon is not all that simple, it's definitely not cheap
(pretty much no matter how you implement it).

Could we please keep this inside osmarender, where it's trivial to do
it, and not make this something that will only work with an external
preprocessor?

-- 
Knut Arne Bjørndal
aka Bob Kåre
bob+osm at cakebox.net
bobkare at irc
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