1.	DTOI INTERACTIVE CURVE FITTING OPTIONS 

?	Print options
a	Add point at the cursor position to sample (from HD curve only)
c	Print the coordinates and fit of point nearest the cursor
d	Delete data point nearest the cursor
f	Fit the data and redraw or overplot
g	Redefine graph keys.  Any of the following data types may be along
	either axis.  
	    x  Independent variable	y  Dependent variable
	    f  Fitted value		r  Residual (y - f)
	    d  Ratio (y / f)		n  Nonlinear part of y
	    u  Density above fog
o	Overplot the next graph
q	Exit the interactive curve fitting.  Carriage return will also exit.
r	Redraw graph
u	Undelete the deleted point nearest the cursor
w	Set the graph window.  For help type 'w' followed by '?'.
x	Change the x value of the point nearest the cursor
y	Change the y value of the point nearest the cursor
z	Change the weight of the point nearest the cursor


2. 	DTOI INTERACTIVE CURVE FITTING 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 [file]		Show the values of all the parameters
:vshow [file]		Show the values of all the parameters verbosely
:errors [file]		Print the errors of the fit (default STDOUT)
:reset			Return to original conditions (x, y, wts and npts)
:ebars [errors/weights]	Error bars can indicate either errors or weights
:function [value]	Fitting function (power, cheby, legen, spline3, spline1)
:transform [value]	Set the transform type (none, logo, k50, k75)
:fog [value]		Change the fog level (or ":fog reset")
:order [value]		Fitting function order
:quit			Terminate HDFIT without updating database

Additional commands are available for setting graph formats and manipulating
the graphics.  Use the following commands for help.

:/help			Print help for graph formatting option
:.help			Print help for cursor mode


3.	DTOI INTERACTIVE CURVE FITTING GRAPH KEYS

The graph keys h, i, j, k, and l indicate the following types of graphs:
h	h = (x,y)  transformed density vs. log exposure
i	i = (y,x)  log exposrue vs. transformed density
j	j = (x,r)  transformed density vs. residuals
k	k = (x,d)  transformed density vs. the y(data)/y(fit) ratio
l	l = (y,u)  log exposure vs. density above fog (HD Curve)

The graph keys may be redefined to put any combination of axes type along 
either graph axis with the 'g' key.  To define a graph key, select the desired 
key to redefine and then specify the axes types for the horizontal and vertical
axes by a pair of comma separated types from the following:

d  Ratio (y / f)
f  Fitted values
r  Residuals of fit (y - f)
n  Nonlinear part of data (linear component of fit subtracted)
x  Indepedent variable
y  Dependent variable (data being fit)
u  User - which for the DTOI package is density above fog