[OSM-talk] Nested areas

[Dave Stubbs]

On Thu, Jun 5, 2008 at 12:28 PM, cobaco (aka Bart Cornelis)
<cobaco at linux.be> wrote:
> On 2008-06-05, Steve Hill wrote:
>> Can areas be nested?
>
> Yes, mapped one recently
>
>> To a human, it is fairly obvious that a small areas which is completely
>> enclosed within a larger area should take presidence, but are the
>> renderers expected to understand this?
>
> I had to add a layer tag to get it rendered correctly, so apperently
> renderers don't currenlty understand this by default, but you can tell them
> about it :)


Layer tags on areas are pure evil. The layer tag is there to indicate
vertical separation, not to give a handy z-order hint to the renderer.
So unless you do genuinely have two areas which are physically
suspended one on top of the other then please don't add layer tags!
Thankfully the mapnik maps will just ignore them.
Instead you should fix the renderer, which may include adding
something like handy_renderer_z_order_hint=1 to your objects if there
isn't a better way.

Dave