WMS Server: Filtering Raster/Vector data based on request params

[Ed McNierney]

Jeremy -

I'll defer to Tom and others on the filtering questions, but I hope you
don't really intend to have a map file with over 100,000 layers!  I am
assuming that those are not 100,000 logically separate layers but rather a
small number of layers each of which is represented by a large number of
individual image files.  If that's the case, you need to consider using a
TILEINDEX mechanism to logically group images together.  The images in a
TILEINDEX layer do not need to be "uniform in size, density, or color model"
- they are just a collection of raster images that are, for the purposes of
your application, a single logical set.

If that is not suitable for you, then I would recommend you consider
creating (in an automated way) a large number of small mapfiles, and using
some logic in constructing your MapServer request to direct each request to
the small mapfile appropriate to that request.  If you do indeed have a
scenario in which only one image is ever used in a request, then you might
actually want to have 100,000 mapfiles, each with one layer.  That will not
be a performance problem, but 100,000 layers in one mapfile will give you
some serious performance challenges.

     - Ed
  
-- 
Ed McNierney
Chief Mapmaker
Demand Media / TopoZone.com
73 Princeton Street, Suite 305
North Chelmsford, MA  01863
Phone: (978) 251-4242
Fax: (978) 251-1396
ed at topozone.com


> From: Jeremy Nix <Jeremy.Nix at SFSLTD.COM>
> Organization: Southwest Financial Services, LTD.
> Reply-To: Jeremy Nix <Jeremy.Nix at SFSLTD.COM>
> Date: Tue, 4 Sep 2007 14:46:24 -0400
> To: <MAPSERVER-USERS at LISTS.UMN.EDU>
> Subject: [UMN_MAPSERVER-USERS] WMS Server: Filtering Raster/Vector data based
> on request params
> 
> I was worried about the negative performance that would
> most likely be involved with have a map file that consisted of 100K+
> layers for all of our image files.