[OSM-talk] Layers query

Tom Chance tom at acrewoods.net
Sun Oct 8 13:09:30 BST 2006


Ahoy,

Can somebody confirm how one should use the layer attribute? The wiki says:

layer   -5 to +5     Use also for display order

So if I have, for example, a footbridge over a railway, do I add "layer=1" to 
the footpath way, and leave the railway at a default (assumed) value of zero? 
That seems to work with osmarender.

Would it be a sensible convention to use negative values if the way goes 
underground, and positive if the way goes over a ground-level feature? So the 
footbridge gets "level=1", and an underpass under a railway would 
get "level=-1" rather than adjusting the railway. That of course doesn't make 
sense for lakes and rivers in parks, which should be "on top" of the park, 
but the convention can be flexible.

If there's a consensus on this I'll add an explanation to the wiki, just to 
make it perfectly clear.

Regards,
Tom

-- 
The struggle against power is the struggle of memory against forgetting
 - Kundera




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