Interactive Keystroke Commands

?	Print options
f	Fit data and graph fit with the current graph type (g,x,r,y,s)
g	Graph the data and the current fit
x,r	Graph the x(in) fit residuals versus x(ref) and y(ref) respectively
y,s	Graph the y(in) fit residuals versus x(ref) and y(ref) respectively
d,u	Delete or undelete the data point nearest the cursor
o	Overplot the next graph
c	Toggle the line of constant x(ref), y(ref) plotting option
t       Plot a line of constant x(ref), y(ref) through nearest data point	
l	Print xshift, yshift, xscale, yscale, xrotate, yrotate
q	Exit the interactive surface fitting code

	Interactive Colon Commands

The parameters are listed or set with the following commands which may be
abbreviated.  To list the value of a parameter type the command alone.

:show	 	     List parameters
:fit 	  [value]    Fit geometry (shift,xyscale,rotate,rscale,rxyscale,general)
:function [value]    Fitting function (chebyshev,legendre,polynomial)
:order	  [value]    X and Y fitting orders in x and y
:xxorder  [value]    X fitting function order in x
:xyorder  [value]    X fitting function order in y
:yxorder  [value]    Y fitting function order in x
:yyorder  [value]    Y fitting function order in y
:xxterms  [n/h/f]    X fit cross terms type
:yxterms  [n/h/f]    Y fit cross terms type
:maxiter  [value]    Maximum number of rejection iterations
:reject   [value]    K-sigma rejection threshold