*!	Help file for program contourplot	version 2.8		by Mead Over	20Oct2017

*	This program assumes that a preceding estimation command
*	has estimated a non-linear function of at least two variables,
*	say -y- and -x-, where the non-linearity is captured by interactions of
*	Stata's continuous factor variables, of the form c.x#c.y.
*	The objective of this program is to construct a graph
*	to trace out level sets of the z-variable at the values
*	defined by the option -ccuts- in order to reveal
*	the shape of a three dimensional surface with the dependent variable
*	on the z-axis (coming out of the page) and the designated y- and
*	x-variables on the vertical (or y) axis and the horizonatal
*	(or x) axis respectivley.

	version 11.1
	syntax  [if/] , zvar(string) yvar(string) xvar(string)  ///
			[xvalues(numlist) yvalues(numlist) slope(real -9) ///  Optional from ver 2.2
			chain(passthru) chainlhs(passthru) chainwrt(passthru) ///
			restore(string) cmdline(string)  ///
			intercept(real 0) level(real 95) verbose replace force ///
			yweight(real 1) name(passthru) saving(passthru) keep ///
			xtitle(string) ytitle(string)  note(passthru) ///
			xmin(string) xmax(string) ymin(string) ymax(string)  ///
			ccuts(passthru) xlabel(passthru) text(passthru)   ///
			TItle(passthru)  xlog ylog ///  Options added July 2016
			LTItle(string) LSUBtitle(string) LSIze(string) LSSize(string)  ///
			ylabel(passthru) ///
			hilite(string) INTerp(passthru)  ///  Options added June 2017
			timer(real 0) CONTstat(string) FVstat(string) SE *]  // Options added Aug & Sep 2017

*  Required parameters:
*	yvar(string)		Variable on vertical axis (typically untransformed) to be assigned name `yvar'_at
*	xvar(string)		Variable on horizontal axis (typically untransformed) to be assigned name `xvar'_at
*	zvar(string)		Predicted variable on z axis (typically untransformed) to be assigned name `zvar'_hat_at
*-----------------------------------------------------------------------------
*  Optionally unwind variable transformations:
*	chain(string)			o	Unwind all three variables, x, y and z
*		Not yet implemented
*	chainlhs(string)		o	Unwind the lhs or z-variable with this trans
*	chainwrt(string)		o	Unwind the x- and y- variables with this trans
*-----------------------------------------------------------------------------
*  Other optional parameters:
*	xvalues(numlist)	list of values of -xvar- at which y will be estimated
*	yvalues(numlist)	list of values of -yvar- at which y will be estimated
*	yweight(real)		The weight to place on the y-variable in computing
*							total output for the average cost function
*	slope(real)			Slope of an expansion ray to be superimposed on the plot
*							(default is to omit plotting a ray fromthe origin)
*	intercept(real)		Intercept on y axis of the ray (default = 0)
*	replace				Overwrite any existing variables with _at
*							suffixes
*	verbose				Requests output of margins commands
*	force				Forces execution despite the prefix of the dependent
*							variable not being the expected one.
*	restore(string)		Name of previously stored estimates to be recalled.
*						Only necessary if they are not currently in memory.
*	xtitle(string)		Specify the title on the X-axis.  Default is X's label
*	ytitle(string)		Specify the title on the Y-axis.  Default is Y's label
*	note(string)		Note to appear at the bottom of the plot. (Default is no note.)
*	text(y x "string")	A text annotation to the graph positioned at (x, y)
*	xmin(string)		Default would be the minimum or maximum of the
*	xmax(string)		corresponding variable/
*	ymin(string)
*	ymax(string)
*	title(passthru)		Title at top of the contourplot.
*	ltitle(string)		Legend title: (Default: Isocost fromtiers)
*	lsubtitle(string)	Legend subtitle (Default: $1,000's)
*	lsize(string)		Legend size (Default: medium)
//  Options added July 2016
*	xlog				Scale the x-axis with option xscale(log)
*	ylog				Scale the y-axis with option yscale(log)
*	LTItle(string)		Legend title
*	LSUBtitle(string) 	Legend subtitle
*	LSIze(string)		Legend title size
*	LSSize(string)		Legend subtitle size
*	xlabel(passthru)	labels for the x-axis
*	ylabel(passthru)	labels for the y-axis
//  Options added June, Aug 2017
*	hilite(string)
*	INTerp(passthru)	Passed to twoway contourline.  See help twoway_contour##interpolation
*	timer(real 0)
*	CONTstat(string) FVstat(string)
//  Options added June, Oct 2017
*	SE					Request -margins- to compute standard errors and upper & lower confidence bounds