[Tilecache] threshold

[Christopher Schmidt]

On Wed, Mar 14, 2007 at 09:24:09AM -0700, Brent Pedersen wrote:
> just looking through this again... i thought this was just a typo, but
> i found it here too:
> http://openlayers.org/pipermail/users/2006-December/000237.html
> 
> why doesnt reproject:false go in the first options hash along with
> layers, format and other stuff that appears in the url?

There are four parameters to an OpenLayers WMS layer:
 * Name
 * URL
 * Parameters
 * Options

Parameters only exist on subclasses of HTTPRequest.

Options are things which control the settings of the layer: they control
things like whether it is a base layer or not, etc. Parameters are meant
to only be used to send data to the server. In some cases
('transparent': true in the case of WMS) the parameters used are used as
fallback mechanism for determining options if they are not set
explicitly.

Options override any 'this' properties on the layer object. Parameters
do not. Options exist on all layers. Parameters do not. Options are
internal to OpenLayers. Parameters get sent to the server. 

This is probably one of the more confusing parts of OpenLayers, and I
don't know how to explain it so people get it. Does this help? Is there 
something I'm not being clear on here? Is there somewhere I can put this
so more people read it and understand it?

Regards,
-- 
Christopher Schmidt
MetaCarta