[Mapserver-dev] suggestion needed for using mapserver as a generic browser of 2000+ layers of data?

[Sean Gillies]

On Monday, December 8, 2003, at 10:15  AM, Stephen Clark wrote:

>
> Hi all,
>
>
> I am working on a project to dynamically display over  2000+ layers of 
> data
> (point, polygons, raster,  etc.) and am interested in finding a way to 
> get
> past the HARD CODED number of layers in mapserver / mapscript *.map 
> files.
> OR maybe there is some
> short term solution for using PHP mapscript to dynamically generate 
> *.map
> files from a list of map files each specified by a type (e.g., raster
> layers, polygon layers, )
>
> Any thoughts?
>
> Also, is there plans to have the HARD CODED number of layers in 
> mapserver
> bug fixed in the 4.1 release?
>
> thanks,
> Stephen
>
>

Stephen,

I have entered two related feature enhancements to Bugzilla that may
interest you:

http://mapserver.gis.umn.edu/bugs/show_bug.cgi?id=357
http://mapserver.gis.umn.edu/bugs/show_bug.cgi?id=358

These are not about increasing the number of possible layers or
making the number of layers dynamically extendable, but are about
a new framework that makes it possible to accomplish your 2000+
layer problem.

I'm proposing that layers be objects that can: 1) exist outside
of a map, 2) be instantiated from a map file "fragment".  In my
use cases, what you would do is either

1) keep map file fragments which completely define a layer as
text/varchar in your favorite RDBMS, allow a user to select
layers, instantiate them from the fragments, then insert the
layer object into a map object for rendering and output.

or 2) store layer objects in an persistent object database
and insert them into a map object as needed.

My proposal primarily concerns MapScript (all flavors) but some
have seen many useful applications for the mapserv app itself.

cheers,
Sean

--
Sean Gillies
sgillies at frii dot com
http://www.frii.com/~sgillies