Compute partial polygon area

[Krung Saengpole]

Hi all,
   
  I'd like to compute partial area of polygon that intersects with another polygon. Is there a way to do with PHPMapscript? For example, I want to know how many square kilometers of forests that reside in the area of 50km-radius circled area. Or where can I get to the example?
   
  Thank you in advance.
  Krung

		
---------------------------------
Yahoo! for Good - Make a difference this year. 
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/mapserver-users/attachments/20051230/f37f99c6/attachment.htm>