SURFACE Procedure

Draws the surface of a two-dimensional array with hidden lines removed.

SURFACE, z [, x, y]

z A two-dimensional array containing the values that make up the surface. If x and y are supplied, the surface is plotted as a function of the X,Y locations specified by their contents. Otherwise, the surface is generated as a function of the array index of each element of z.

x (optional) A vector or two-dimensional array specifying the x-coordinates for the surface.

• If x is a vector, each element of x specifies the x-coordinate for a column of z. For example, x(0) specifies the x-coordinate for z(0, *).

• If x is a two-dimensional array, each element of x specifies the x-coordinate of the corresponding point in z (x_ij specifies the x-coordinate for z_ij).

y (optional) A vector or two-dimensional array specifying the y-coordinates for the surface.

• If y is a vector, each element of y specifies the y-coordinate for a row of z. For example, y(0) specifies the y-coordinate for z (*, 0).

• If y is a two-dimensional array, each element of y specifies the y-coordinate of the corresponding point in z (y_ij specifies the y-coordinate for z_ij).

Keywords let you control many aspects of the plot's appearance. SURFACE keywords are listed below. For a description of each keyword, see Chapter 3, Graphics and Plotting Keywords.

Discussion

Note the following restrictions on the use of SURFACE. If the X,Y grid is not regular or nearly regular, errors in hidden line removal will occur.

If the T3D keyword is set, the 3D to 2D ;transformation matrix contained in !P.T must project the Z axis to a line parallel to the device Y axis, or errors will occur.

This example displays the surface described by the function

.RUN

FUNCTION f, x, y
RETURN, x * SIN(y) + y * COS(x)
END

; Define the function.

x = FINDGEN(101)/5-10

; Create vector of x-coordinates.

y = x

; Create vector of y-coordinates.

z = FLTARR(101, 101)

; Create an array to hold the function values.

FOR i = 0, 100 DO FOR j = 0, 100 DO z(i, j) = f(x(i), y(j))

; Evaluate the function at the given x- and y-coordinates and

; place the result in z.

SURFACE, z, x, y, Ax = 50, XCharsize = 2, $
    YCharsize = 2, ZCharsize = 2

; Display the surface. The Ax keyword is used to specify the

; angle of rotation about the x-axis. The XCharsize, YCharsize,

; and ZCharsize keywords are used to enlarge the characters

; used to annotate the axes.

XYOUTS, 163, 477, $
"f(x, y) = x*sin(y) + y*cos(x)", Charsize = 2, /Device

; Place a title on the window. Note that the CURSOR procedure

; with the Device keyword was used to locate the proper position

; for the title.

SHADE_SURF, SHADE_SURF_IRR, SURFACE_FIT, SURFR, T3D, THREED

System Variables: !P.T

For more information, see Chapter 5, Displaying 3D Data, in the PV-WAVE Programmer's Guide.