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 xi fit residuals versus x and y respectively
y,s	Graph the eta fit residuals versus x and y respectively
d,u	Delete or undelete the data point nearest the cursor
o	Overplot the next graph
c	Toggle the line of constant x and y plotting option
t       Plot a line of constant x and y through nearest data point	
l	Print xishift, etashift, 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
:projection          Sky projection (lin,tan,arc,sin,tnx, ...)
:refpoint	     Sky projection reference point
:fit 	  [value]    Fit geometry (shift,xyscale,rotate,rscale,rxyscale,general)
:function [value]    Fitting function (chebyshev,legendre,polynomial)
:order	  [value]    Xi and Eta fitting orders in x and y
:xxorder  [value]    Xi fitting function order in x
:xyorder  [value]    Xi fitting function order in y
:yxorder  [value]    Eta fitting function order in x
:yyorder  [value]    Eta fitting function order in y
:xxterms  [y/n]      Include cross-terms in xi fit
:yxterms  [y/n]	     Include cross-terms in eta fit
:maxiter  [value]    Maximum number of rejection iterations
:reject   [value]    K-sigma rejection threshold