On Thu, Jan 08, 2009 at 05:47:09PM -0000, Donald Kerr wrote: > I'd appreciate it if someone could give me some clarification please? > > I am using the following url to return an image: > > http://localhost/cgi-bin/mapserv.exe?map=/ms4w/os.map&mode=map&mapsize=500+4 > 00&mapxy=258544+665909&layers=all&buffer=2000 > > The documentation states, "BUFFER [distance] - A distance, in the same > coordinate system as the map file, used in conjunction with MAPXY to create > an new map extent". > > The coordinate system is in metres so I would expect that the width of the > image (500px) would be 2000m (2km). That doesn't seem to be the case i.e. > the returned images is, at a guess, double that.
"Buffer" is usually a 'radius' -- so, you've got 2000M on each side (4k total, instead of the 2k you expect). If you imagine picking the center piont, and drawing a $buffer_size circle around it -- that's your extent. Regards, -- Christopher Schmidt MetaCarta _______________________________________________ mapserver-users mailing list mapserver-users@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/mapserver-users