grayplot
========

2D plot of a surface using colors



Calling Sequence
~~~~~~~~~~~~~~~~


::

    grayplot(x,y,z,[strf,rect,nax])
    grayplot(x,y,z,<opt_args>)




Arguments
~~~~~~~~~

:x,y real row vectors of size n1 and n2.
: :z real matrix of size (n1,n2). `z(i,j)` is the value of the surface
  at the point (x(i),y(j)).
: :<opt_args> This represents a sequence of statements `key1=value1,
  key2=value2` ,... where `key1`, `key2,...` can be one of the
  following: rect, nax, strf or axesflag and frameflag (see `plot2d`).
: :strf,rect,nax see `plot2d`.
:



Description
~~~~~~~~~~~

`grayplot` makes a 2D plot of the surface given by `z` on a grid
defined by `x` and `y`. Each rectangle on the grid is filled with a
gray or color level depending on the average value of `z` on the
corners of the rectangle. If z contains %nan values, the surounding
rectangles are not displayed.

Enter the command `grayplot()` to see a demo.



Sample
~~~~~~



Examples
~~~~~~~~


::

    x=-10:10; y=-10:10;m =`rand`_(21,21);
    grayplot(x,y,m,rect=[-20,-20,20,20])
    t=-%pi:0.1:%pi; m=`sin`_(t)'*`cos`_(t);
    `clf`_()
    grayplot(t,t,m)




See Also
~~~~~~~~


+ `fgrayplot`_ 2D plot of a surface defined by a function using colors
+ `plot2d`_ 2D plot
+ `Sgrayplot`_ smooth 2D plot of a surface using colors
+ `Sfgrayplot`_ smooth 2D plot of a surface defined by a function
  using colors


.. _Sfgrayplot: Sfgrayplot.html
.. _plot2d: plot2d.html
.. _fgrayplot: fgrayplot.html
.. _Sgrayplot: Sgrayplot.html