us - Make changes in the use array				RWW

us			The use array is set for all chans.
us 40_50		If the current plot is in chans, the use array will
			be cleared for chans 40 to 50. If the plot is in
			velocity, channels in the range 40 to 50 km/s will
			be cleared.
cr,2;us x(0)_x(1) ref:	The cursor's will be read twice to find the range
			of chans to be cleared. A similar range will be
			cleared around the reference chan
us st:			Store the use array so that future gt's and rt's.
			will use it.
us 40_50 rt:s:		Retrieve the stored use array and then set chans 
			40 to 50(if plotting chans).

The normal action of use is to reset 'r' or set 's' a range of channels
in the use array. The horizontal range to be acted on is expressed in
the current horizontal plot units (channels, velocity, or frequency) It
may also be given using the cursor.

Additional functions retrieve 'rt' the stored use array and/or
compliment 'co' the use array before the 'r' or 's' action is
considered. After the 'r' or 's' action, the 'ref' flag causes freq
switched data to have that function repeated after being shifted by ref
- sig channels. The final action which is possible is to store the
resulting use array for later use. The stored use array can be
retrieved either when specifically requested or when new data is
obtained by get or retrieve (but see retrieve for the stack use
option).  Any combination of the above actions is possible.

If the range of horizontal values is not given, there are three possible
	1) If the 'r' or 's' flag is given, the use array will be reset or set
	for all chans in stack1.
	2) As a special case which violates one's expectation of the input
	tree, us with no arguments will set all chans of the use array.
	3) If 'r' and 's' are not given, but other function(s) are, only the
	specified functions will be performed.

'uscr', 'uscm', and 'usst' are macros to clear or set the use array with 
the cursor.  They reside in .GMACROS (dm g:).

This document was last updated on Tue Oct 17 16:24:05 EDT 2000 by Marc W. Pound.