#### 30.1.1 Plotting the Triangulation

Octave has the functions `triplot`, `trimesh`, and `trisurf` to plot the Delaunay triangulation of a 2-dimensional set of points.

— Function File: triplot (tri, x, y)
— Function File: triplot (tri, x, y, linespec)
— Function File: h = triplot (...)

> Plot a triangular mesh in 2D. The variable tri is the triangular meshing of the points `(`x`,` y`)` which is returned from `delaunay`. If given, linespec determines the properties to use for the lines.

> The optional return value h is a graphics handle to the created plot.

> See also: plot, trimesh, trisurf, delaunay.

— Function File: trimesh (tri, x, y, z)
— Function File: h = trimesh (...)

> Plot a triangular mesh in 3D. The variable tri is the triangular meshing of the points `(`x`,` y`)` which is returned from `delaunay`. The variable z is value at the point `(`x`,` y`)`.

> The optional return value h is a graphics handle to the created plot.

> See also: triplot, trisurf, delaunay3.

— Function File: trisurf (tri, x, y, z)
— Function File: h = trisurf (...)

> Plot a triangular surface in 3D. The variable tri is the triangular meshing of the points `(`x`,` y`)` which is returned from `delaunay`. The variable z is value at the point `(`x`,` y`)`.

> The optional return value h is a graphics handle to the created plot.

> See also: triplot, trimesh, delaunay3.

The difference between `triplot`, and `trimesh` or `triplot`, is that the former only plots the 2-dimensional triangulation itself, whereas the second two plot the value of a function `f (`x`,` y`)`. An example of the use of the `triplot` function is

         rand ("state", 2)
         x = rand (20, 1);
         y = rand (20, 1);
         tri = delaunay (x, y);
         triplot (tri, x, y);

which plots the Delaunay triangulation of a set of random points in 2-dimensions. The output of the above can be seen in fig:triplot.

Figure 30.2: Delaunay triangulation of a random set of points