~F8DATA STRUCTURE: LINK AND DATUM NAMES.
	
	Nodes  contain either  numerical data  or  pointers to  other
nodes;  such  node  pointers are  actual  machine  addresses and  are
called links. The positions within a node where a link is  stored are
named and  are reserved for particular  uses. In the table  below the
11  link names  and 13 datum  names are  introduced.   The link names
will always appear capitalized.

	11 LINK NAMES:

		CW	clockwise
		CCW	counter clockwise
		DAD	parent of node up a tree structure.
		SON	descendent of a node down a tree structure.
		ENDO	Greek for inside, polygon within.
		EXO	Greek for outside, surrounding polygon.
		ALT	alternate.
		NGON	negative polygon.
		PGON	positive polygon.
		NTIME	negative in real time, into the past.
		PTIME	positive in real time, into the future.

	13 DATUM NAMES:

	   Boolean datums.

		type		type of node bits.
		reloc		rellocation of node bits.

	   Fixed point datums.

		row		row of image locus.
		col		column of image locus.
		cntrst		contrast of an edge, vector and arc.
		ncnt		number count, various uses.

	   Floating point datums.

		zdepth		z depth from camera lens center.
		perm		length of perimeter.
		area		area in pixel units.
		mxx		moment of inertia about X axis.
		myy		moment of inertia about Y axis.
		mzz		moment of inertia about Z axis.
		pxy		product of inertia with respect
				to the X and Y axes.
~I1973,800;F8- 8 -