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.. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE:
.. "basic_examples/plot_terrain_attributes.py"
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.. only:: html

    .. note::
        :class: sphx-glr-download-link-note

        :ref:`Go to the end <sphx_glr_download_basic_examples_plot_terrain_attributes.py>`
        to download the full example code.

.. rst-class:: sphx-glr-example-title

.. _sphx_glr_basic_examples_plot_terrain_attributes.py:


Terrain attributes
==================

Terrain attributes generated from a DEM have a multitude of uses for analytic and visual purposes.
Here is an example of how to generate these products.

As a reminder: the slope, aspect, and hillshade are calculated following Horn (1981); the system of curvatures follows that described by Minár et al. (2020)l and the terrain ruggedness index and rugosity follow Riley et al. (1999) and Jenness (2004), respectively. For more information, see the :ref:`terrain-attributes` feature page.

**References:** `Horn (1981) <https://ieeexplore.ieee.org/document/1456186>`_ (slope, aspect, hillshade),
`Minár et al. (2020) <[Minár et al. (2020)](https://doi.org/10.1016/j.earscirev.2020.103414)>`_ (curvature),
`Riley et al. (1999) <http://download.osgeo.org/qgis/doc/reference-docs/Terrain_Ruggedness_Index.pdf>`_ (terrain
ruggedness index), `Jenness (2004) <https://doi.org/10.2193/0091-7648(2004)032%5B0829:CLSAFD%5D2.0.CO;2>`_ (rugosity).

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.. code-block:: Python


    import matplotlib.pyplot as plt

    import xdem








.. GENERATED FROM PYTHON SOURCE LINES 22-23

We load the example data.

.. GENERATED FROM PYTHON SOURCE LINES 23-26

.. code-block:: Python


    dem = xdem.DEM(xdem.examples.get_path("longyearbyen_ref_dem"))








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We generate multiple terrain attribute at once (more efficient computationally as some depend on each other).

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.. code-block:: Python


    attributes = xdem.terrain.get_terrain_attribute(
        dem.data,
        resolution=dem.res,
        attribute=["hillshade", "slope", "aspect", "profile_curvature", "terrain_ruggedness_index", "rugosity"],
    )

    plt.figure(figsize=(8, 6.5))

    plt_extent = [dem.bounds.left, dem.bounds.right, dem.bounds.bottom, dem.bounds.top]

    cmaps = ["Greys_r", "Reds", "twilight", "RdGy_r", "Purples", "YlOrRd"]
    labels = ["Hillshade", "Slope (°)", "Aspect (°)", "Profile Curvature (100 / m)", "Terrain Ruggedness Index", "Rugosity"]
    vlims = [(None, None) for i in range(6)]
    vlims[3] = [-2, 2]

    for i in range(6):
        plt.subplot(3, 2, i + 1)
        plt.imshow(attributes[i].squeeze(), cmap=cmaps[i], extent=plt_extent, vmin=vlims[i][0], vmax=vlims[i][1])
        cbar = plt.colorbar()
        cbar.set_label(labels[i])
        plt.xticks([])
        plt.yticks([])

    plt.tight_layout()
    plt.show()



.. image-sg:: /basic_examples/images/sphx_glr_plot_terrain_attributes_001.png
   :alt: plot terrain attributes
   :srcset: /basic_examples/images/sphx_glr_plot_terrain_attributes_001.png
   :class: sphx-glr-single-img






.. rst-class:: sphx-glr-timing

   **Total running time of the script:** (0 minutes 2.243 seconds)


.. _sphx_glr_download_basic_examples_plot_terrain_attributes.py:

.. only:: html

  .. container:: sphx-glr-footer sphx-glr-footer-example

    .. container:: sphx-glr-download sphx-glr-download-jupyter

      :download:`Download Jupyter notebook: plot_terrain_attributes.ipynb <plot_terrain_attributes.ipynb>`

    .. container:: sphx-glr-download sphx-glr-download-python

      :download:`Download Python source code: plot_terrain_attributes.py <plot_terrain_attributes.py>`

    .. container:: sphx-glr-download sphx-glr-download-zip

      :download:`Download zipped: plot_terrain_attributes.zip <plot_terrain_attributes.zip>`


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