[mapserver-users] dynamic layer classification

[Brent Fraser]

Puneet,

   I think currently the short answer is Mapscript.

   I had a similar need last year 
(http://lists.osgeo.org/pipermail/mapserver-users/2010-March/065050.html) where 
I needed to have the symbology stored in the database and the classes 
varied over  time (users created new class defs in the database via a 
web page).

   Steve Lime suggested an enahancement where classes were defined by a 
SLD file or url:

LAYER
   NAME 'extreme-symbology'
   DATA ...
   CONNECTION ...
   SLD 'some flle' or 'some url'
   ...
END

which is an elegant solution, but currently not implemented...

Best Regards,
Brent Fraser


On 8/26/2011 8:35 AM, Mr. Puneet Kishor wrote:
> hola,
>
> I need some guidance on this (and my MapServer foo is severely rusted). My immediate need is to color a polygon layer (held in PostGIS) based on an attribute in a separate table. The number of CLASSes is considerable, more than 80 or so. This leads to a longer term need --
>
> The coloring of these polys is a crucial and universal need in my field of work, and it horrendously complicated determining the correct color, and the calculations for the appropriate color keep on changing from time to time. In other words, many different applications need this ability to classify polys based on certain attributes. So, I am creating a web app that does nothing but tell what color to use -- you give it a set of attributes, and the web app replies with the color. It would be a RESTful app, sending the color information back as JSON. How could I use this information with MapServer?
>
> In an ideal scenario, MapServer would query the data source, then, for each class in the layer, it would send a query to this color app, and the color app would tell MapServer what color to use to render the poly. The same app would be used by other apps, be they MapServer, OL, Polymaps, or even non-mapping apps such as R, etc.
>
> Suggestions on how to proceed?
>
> --
> Puneet Kishor
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