.. DO NOT EDIT. .. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY. .. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE: .. "auto_examples/surface_analyses/plot_tissots_indicatrix.py" .. LINE NUMBERS ARE GIVEN BELOW. .. only:: html .. note:: :class: sphx-glr-download-link-note Click :ref:`here ` to download the full example code .. rst-class:: sphx-glr-example-title .. _sphx_glr_auto_examples_surface_analyses_plot_tissots_indicatrix.py: =================== Tissot's Indicatrix =================== Creating a flatmap from a folded cortical surface always introduces some distortion. This is similar to what happens when a map of the globe is flattened into a 2-D map like a Mercator projection. For the cortical surface the amount and type of distortion will depend on the curvature of the surface (i.e. whether it is on a gyrus or a sulcus) and on the distance to the nearest cut. In general, we recommend examining data both in flattened and original 3-D space using the interactive webGL viewer, but it is also informative to visualize the distortion directly. One method to show distortion is to visualize how geodesic discs, which contain all of the points within some geodesic distance of a central point, appear on the flattened cortical surface. This technique is traditionally used to characterize and visualize distortions introduced by flattening the globe onto a map: .. image::https://upload.wikimedia.org/wikipedia/commons/8/87/Tissot_mercator.png .. GENERATED FROM PYTHON SOURCE LINES 26-35 .. image-sg:: /auto_examples/surface_analyses/images/sphx_glr_plot_tissots_indicatrix_001.png :alt: plot tissots indicatrix :srcset: /auto_examples/surface_analyses/images/sphx_glr_plot_tissots_indicatrix_001.png :class: sphx-glr-single-img .. rst-class:: sphx-glr-script-out Out: .. code-block:: none Generating tissots_indicatrix surface info... /opt/hostedtoolcache/Python/3.9.12/x64/lib/python3.9/site-packages/scipy/sparse/linalg/_dsolve/linsolve.py:322: SparseEfficiencyWarning: splu requires CSC matrix format warn('splu requires CSC matrix format', SparseEfficiencyWarning) Adding vertex 88060.. Adding vertex 93467.. Adding vertex 51981.. Adding vertex 142197.. Adding vertex 104363.. Adding vertex 37286.. Adding vertex 34977.. Adding vertex 14831.. Adding vertex 3410.. Adding vertex 34140.. Adding vertex 63509.. Adding vertex 117329.. Adding vertex 151274.. Adding vertex 83445.. Adding vertex 112573.. Adding vertex 69703.. 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Adding vertex 40064.. /opt/hostedtoolcache/Python/3.9.12/x64/lib/python3.9/site-packages/numpy/lib/npyio.py:713: VisibleDeprecationWarning: Creating an ndarray from ragged nested sequences (which is a list-or-tuple of lists-or-tuples-or ndarrays with different lengths or shapes) is deprecated. If you meant to do this, you must specify 'dtype=object' when creating the ndarray. val = np.asanyarray(val) | .. code-block:: default import cortex import matplotlib.pyplot as plt tissot = cortex.db.get_surfinfo("S1", "tissots_indicatrix", radius=10, spacing=30) tissot.cmap = 'plasma' cortex.quickshow(tissot, with_labels=False, with_rois=False, with_colorbar=False) plt.show() .. rst-class:: sphx-glr-timing **Total running time of the script:** ( 0 minutes 33.731 seconds) .. _sphx_glr_download_auto_examples_surface_analyses_plot_tissots_indicatrix.py: .. only :: html .. container:: sphx-glr-footer :class: sphx-glr-footer-example .. container:: sphx-glr-download sphx-glr-download-python :download:`Download Python source code: plot_tissots_indicatrix.py ` .. container:: sphx-glr-download sphx-glr-download-jupyter :download:`Download Jupyter notebook: plot_tissots_indicatrix.ipynb ` .. only:: html .. rst-class:: sphx-glr-signature `Gallery generated by Sphinx-Gallery `_