[OpenLayers-Users] layers limit

[Tim Schaub]

Hey-

Mick Jagger wrote:
> Hi,
> 	Is there a limit to the number of layers that OpenLayers supports?  I have a page with 63 layers and I get errors with Internet Explorer at layer 60, while Firefox and Opera load the page fine, albeit slowly.  Normally there are only a couple layers, but this is an odd case.
> 

Layers get placed in the z-index hierarchy based on their "type".  There 
are spaces for 45 (225 / 5) layers between your first "base layer" and 
your first "overlay".  After this, things start overlapping (base layers 
over overlays).  Similarly, there is room for 65 "overlay" layers (325 / 
5) under any "popup" layers.  Finally, you get 50 "popup" layers before 
you start overlapping the controls.

None of these numbers matches the limit of 60 that you are asking about, 
but the idea is that browsers start to break down before either of these 
thresholds is met.

There is likely a better way to do things than adding 60ish layers to 
your map at a time.

Tim