Bart's right, file an enhancement request. This could be quite an expensive
computation for most datasources. One approach would be to develop a layer "item
stats" file that could be used to hold such information, and then write a small
program to build the file (much like shptree). Could store min/max, distinct
value list and other things. A naming convention like "layername.column.stat"
might work nicely. Then when a layer is opened it's stat(s) files could be
opened if necessary. Just thinking out loud...
Steve
>>> Bart van den Eijnden <bartvde@XS4ALL.NL> 3/2/2005 3:59:16 AM >>>
Hi,
you could go and talk to the uDig people (udig.refractions.net), they
must have encountered the same problem and maybe found a workaround.
In the meantime, maybe it is wise to file an enhancement bug for
Mapserver WFS for support of min/max functions.
Best regards,
Bart
> Hi,
>
> My working group are thinking about how can one independent application
> that use WFS, WMS SLD and Filter encoding, create SLD to define Styles in
> similar manner that GIS desktop software do it. If one user need define
> regular intervals from one feature attribute, application need known Max & Min
> values of attribute.
> We have revised filter encoding specification (OGC) and this operation are
> enumerated as possible, but no open Source WFS implementation include.
>
> Regards,
>
