[mapserver-users] Clipping

[José María Michia]

2008/12/22 Joshua Hevenor <jhevenor at rogers.com>:
> Good morning list,
> I'm looking for a function and/or method to clip a polygon. In general, I
> need to limit a polygon to the map boundary for export (export as shapefile
> from a web map)...so if I had a 20x20 square that was overlapping
> the visible map by 10 units, the exported result would be a 10x20
> rectangle.  PHP MapScript is my weapon of choice.  I'd also welcome opinions
> on the approach or suggestions for alternatives.
>
> Thanks for your assistance,
>
> Josh
>
> PS.  Sorry for the re-post...forgot the subject

I don't know how to make this using only PHP,  but combining with
postgis, you can clip geometries using something like:

SELECT intersection(the_Geom, <box3d>) FROM <table> WHERE the_Geom && <box3d>;

Saludos
José María