
plsurf3d: Plot shaded 3-d surface plot 

DESCRIPTION:

	Plots a three dimensional shaded surface plot within the environment
	set up by plw3d.  The surface is defined by the two-dimensional array
	z[
	nx][
	ny], the point z[i][j] being the value of the function at (
	x[i], 
	y[j]).	Note that the points in arrays x and y do not need to be
	equally spaced, but must be stored in ascending order. For further
	details see the PLplot documentation. 

SYNOPSIS:

plsurf3d(x, y, z, nx, ny, opt, clevel, nlevel)

ARGUMENTS:

    x (PLFLT *, input) :    Pointer to set of x coordinate values at which
        the function is evaluated. 

    y (PLFLT *, input) :    Pointer to set of y coordinate values at which
        the function is evaluated. 

    z (PLFLT **, input) :     Pointer to a vectored two-dimensional array
        with set of function values. 

    nx (PLINT, input) :    Number of x values at which function is
        evaluated. 

    ny (PLINT, input) :    Number of y values at which function is
        evaluated. 

    opt (PLINT, input) :    Determines the way in which the surface is
        represented. To specify more than one option just add the options,
        e.g. FACETED + SURF_CONT opt=FACETED: Network of lines is drawn
        connecting points at which function is defined. 
            opt=BASE_CONT: A contour plot is drawn at the base XY plane
            using parameters  
    nlevel and 
    clevel. 
            opt=SURF_CONT: A contour plot is drawn at the surface plane
            using parameters  
    nlevel and 
    clevel. 
            opt=DRAW_SIDES: draws a curtain between the base XY plane and
            the borders of the plotted function. 


    clevel (PLFLT *, input) :     Pointer to the array that defines the
        contour level spacing. evaluated. 

    nlevel (PLINT, input) :    Number of elements in the clevel array. 
