.. _example_canyon_decimation: Canyon decimation example -------------------------------------------------------------------- Use the greedy-terrain-decimator to display a decimated terrain view. This example illustrates decimating a terrain. We use the greedy-terrain-decimator to create a reduced mesh with an optimized grid that approximates the initial regular grid. The initial grid is displayed in white, and the optimized grid is displayed in black, with the surface it creates. The initial grid can be seen disappearing as it goes under the surface of the approximated grid: although the decimated mesh follows closely the original, it is not exactly the same. One can see that the reduction in number of polygons is huge: the white grid is much finer than the black grid. It is interesting to note that the decimated mesh follows closely the original mesh, including in number of polygons, in spots where the terrain changes most quickly. This example uses the Grand Canyon topological radar data, from NASA. The greedy-terrain-decimator is only useful to decimate a surface warped from 2D data. To decimated more general meshes, you can use the less-efficient decimate-pro filter (see :ref:`example_julia_set_decimation`). .. image:: ../generated_images/example_canyon_decimation.jpg :align: center **Python source code:** :download:`canyon_decimation.py` .. literalinclude:: canyon_decimation.py :lines: 25-