Scilab Function
Last update : 04/05/2005

grayplot - 2D plot of a surface using colors

### Calling Sequence

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

### Parameters

- `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` and `plot2d_old_version`).
- `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.

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

### 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`, `plot2d`, `Sgrayplot`, `Sfgrayplot`,

### Author

J.Ph.C.