define	IGSPARAMS	7

define	FEATURE	1
define	X	2
define	Y	3
define	Z	4
define	W	5
define	S	6
define	R	7

define	IGS_FUNCTION	1
define	IGS_XORDER	2
define	IGS_YORDER	3
define	IGS_XMIN	4
define	IGS_XMAX	5
define	IGS_YMIN	6
define	IGS_YMAX	7
define	IGS_OFFSET	8

define	SFTYPES		"|chebyshev|legendre|"		# Surface types