**surf_test**,
a MATLAB code which
calls surf(), which
demonstrates the display of a 3D surface or contour plot for data
of the form Z=F(X,Y).

The computer code and data files described and made available on this web page are distributed under the GNU LGPL license.

**surf_test** is available in
a MATLAB version.

contour_gradient, a MATLAB code which displays contours and gradient vectors for a function f(x,y).

contour_gradient_3d, a MATLAB code which shows how contours and gradient vectors for a function f(x,y) can be displayed in a 3D plot.

levels, a MATLAB code which makes a contour plot of a function Z=F(X,Y), choosing the contour levels using random sampling.

shoreline, a MATLAB code which tries to identify and triangulate the 2D domain over which some function f(x,y) is nonnegative.

test_interp_2d, a MATLAB code which defines test problems for interpolation of regular or scattered data z(x,y), depending on a 2D argument.

voronoi_mountains, a MATLAB code which makes a mountain plot of a Voronoi diagram, that is, a surface plot of the distance from each point to its nearest Voronoi generator.

- surf_test.m calls all the tests.
- surf_test.sh runs all the tests.
- surf_test.txt the output file.

- surf_test01.m displays a surface related to the MATLAB peaks() function, using red to highlight the regions where Z > 1.5.
- timestamp.m is a script which prints prints the YMDHMS date as a timestamp;

- surf_test01_2d.png an "overhead" view of the highlighted region.
- surf_test01_3d.png a 3D view of the highlighted region.