plotSurface
==============================================

Purpose
----------------

Graphs a 3-D surface.

Format
----------------
.. function:: plotSurface([myPlot, ]x, y, z)

    :param myPlot: Optional argument, a :class:`plotControl` structure.
    :type myPlot: struct

    :param x: the x-axis data.
    :type x: 1xK vector

    :param y: the y-axis data.
    :type y: Nx1 vector

    :param z: the matrix of height data to be plotted.
    :type z: NxK matrix

Examples
----------------

::

    // Clear out variables in GAUSS workspace
    new;

    // Create contour data
    x = seqa(-4, 0.1, 50)';
    y = x';
    z = sin(y) .* cos(x) ;

    // Set up control structure with defaults
    // for surface plots
    struct plotControl myPlot;
    myPlot = plotGetDefaults("surface");

    // Set color map
    plotSetColormap(&myPlot, "plasma");

    // Draw graph using plotcontrol structure
    plotSurface(myPlot, x, y, z);

.. figure:: _static/images/plotsurf.png

.. seealso:: Functions :func:`plotSetColorMap`, :func:`plotContour`, :func:`plotSetBkdColor`