On 12/10/2010 17:51, Nathan Edgars II wrote:
On Tue, Oct 12, 2010 at 11:26 AM, Pieren<[email protected]> wrote:
"layer" is just saying what is on the top when two objects/lines are
crossing each other. If you have only one element, the layer tag is really
optionnal (this until someone is tracing what is below).
Even if you have two elements, it's obvious which is above the other
if only one is bridge=* or tunnel=*. The purpose of the layer tag is
to resolve ambiguities when two above-ground or two below-ground
features cross.
And we can also put the layer tag on the element under the bridge.
Remembering of course that the ground is layer=0, so unless something
under a bridge is in a tunnel it too is layer=0.
What layer is the road on which connects the rest of the road network at
ground level (layer=0) to the bridge itself (layer=n>0)? I seem to
remember a discussion about joining ways on different layers..can't
remember the full conclusion but I believe it was that the layer tag is
only for rendering purposes and doesn't imply anything reliably about
above/below.
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