.. _anim02:

(2) Examining DEMs using variable illumination
----------------------------------------------

Our next animation uses a gridded topography for parts of Colorado (US).
Here, we want to use :doc:`grdimage </grdimage>` to generate a shaded-relief
image sequence in which we sweep the illumination azimuth around the
entire horizon. The resulting animation illustrates how changing the
illumination azimuth can bring out subtle features (or artifacts) in the
gridded data. The red arrow points to where the light source is located.

.. literalinclude:: /_verbatim/anim02.txt
   :language: bash

..  youtube:: WQ6JrtEu_Fk
    :width: 100%
