How to get the map's EXTENT

[周永豪]

I'm a newbie of Mapserver, now I create a new project with some shapefile and tif map files, to build a web-gis sample.
Now I'm quite comfused about the EXTENT parameters in the XXX.map file when I use the 3rd-party Map data files. 

Does the paremeters of the shapefile file, which are got by ogrinfo, are just the ones in the XXX.map file ?

or any suggetion about how to define the EXTENT paremeter is appreciated~  

Thanks in advance.
	

　　Best wishes ^_^
 				

　　　　　　　　Leo Chou
　　　　　　　　hust_blood at 163.com
　　　　　　　　　　2007-04-15