
.. DO NOT EDIT.
.. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY.
.. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE:
.. "gallery/axisartist/demo_curvelinear_grid.py"
.. LINE NUMBERS ARE GIVEN BELOW.

.. only:: html

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

        Click :ref:`here <sphx_glr_download_gallery_axisartist_demo_curvelinear_grid.py>`
        to download the full example code

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

.. _sphx_glr_gallery_axisartist_demo_curvelinear_grid.py:


=====================
Curvilinear grid demo
=====================

Custom grid and ticklines.

This example demonstrates how to use
`~.grid_helper_curvelinear.GridHelperCurveLinear` to define custom grids and
ticklines by applying a transformation on the grid.  This can be used, as
shown on the second plot, to create polar projections in a rectangular box.

.. GENERATED FROM PYTHON SOURCE LINES 13-120



.. image:: /gallery/axisartist/images/sphx_glr_demo_curvelinear_grid_001.png
    :alt: demo curvelinear grid
    :class: sphx-glr-single-img





.. code-block:: default


    import numpy as np

    import matplotlib.pyplot as plt
    from matplotlib.projections import PolarAxes
    from matplotlib.transforms import Affine2D

    from mpl_toolkits.axisartist import (
        angle_helper, Subplot, SubplotHost, ParasiteAxesAuxTrans)
    from mpl_toolkits.axisartist.grid_helper_curvelinear import (
        GridHelperCurveLinear)


    def curvelinear_test1(fig):
        """
        Grid for custom transform.
        """

        def tr(x, y):
            x, y = np.asarray(x), np.asarray(y)
            return x, y - x

        def inv_tr(x, y):
            x, y = np.asarray(x), np.asarray(y)
            return x, y + x

        grid_helper = GridHelperCurveLinear((tr, inv_tr))

        ax1 = Subplot(fig, 1, 2, 1, grid_helper=grid_helper)
        # ax1 will have a ticks and gridlines defined by the given
        # transform (+ transData of the Axes). Note that the transform of
        # the Axes itself (i.e., transData) is not affected by the given
        # transform.

        fig.add_subplot(ax1)

        xx, yy = tr([3, 6], [5, 10])
        ax1.plot(xx, yy, linewidth=2.0)

        ax1.set_aspect(1)
        ax1.set_xlim(0, 10)
        ax1.set_ylim(0, 10)

        ax1.axis["t"] = ax1.new_floating_axis(0, 3)
        ax1.axis["t2"] = ax1.new_floating_axis(1, 7)
        ax1.grid(True, zorder=0)


    def curvelinear_test2(fig):
        """
        Polar projection, but in a rectangular box.
        """

        # PolarAxes.PolarTransform takes radian. However, we want our coordinate
        # system in degree
        tr = Affine2D().scale(np.pi/180, 1) + PolarAxes.PolarTransform()
        # Polar projection, which involves cycle, and also has limits in
        # its coordinates, needs a special method to find the extremes
        # (min, max of the coordinate within the view).
        extreme_finder = angle_helper.ExtremeFinderCycle(
            nx=20, ny=20,  # Number of sampling points in each direction.
            lon_cycle=360, lat_cycle=None,
            lon_minmax=None, lat_minmax=(0, np.inf),
        )
        # Find grid values appropriate for the coordinate (degree, minute, second).
        grid_locator1 = angle_helper.LocatorDMS(12)
        # Use an appropriate formatter.  Note that the acceptable Locator and
        # Formatter classes are a bit different than that of Matplotlib, which
        # cannot directly be used here (this may be possible in the future).
        tick_formatter1 = angle_helper.FormatterDMS()

        grid_helper = GridHelperCurveLinear(
            tr, extreme_finder=extreme_finder,
            grid_locator1=grid_locator1, tick_formatter1=tick_formatter1)
        ax1 = SubplotHost(fig, 1, 2, 2, grid_helper=grid_helper)

        # make ticklabels of right and top axis visible.
        ax1.axis["right"].major_ticklabels.set_visible(True)
        ax1.axis["top"].major_ticklabels.set_visible(True)
        # let right axis shows ticklabels for 1st coordinate (angle)
        ax1.axis["right"].get_helper().nth_coord_ticks = 0
        # let bottom axis shows ticklabels for 2nd coordinate (radius)
        ax1.axis["bottom"].get_helper().nth_coord_ticks = 1

        fig.add_subplot(ax1)

        ax1.set_aspect(1)
        ax1.set_xlim(-5, 12)
        ax1.set_ylim(-5, 10)

        ax1.grid(True, zorder=0)

        # A parasite axes with given transform
        ax2 = ParasiteAxesAuxTrans(ax1, tr, "equal")
        # note that ax2.transData == tr + ax1.transData
        # Anything you draw in ax2 will match the ticks and grids of ax1.
        ax1.parasites.append(ax2)
        ax2.plot(np.linspace(0, 30, 51), np.linspace(10, 10, 51), linewidth=2)


    if __name__ == "__main__":
        fig = plt.figure(figsize=(7, 4))

        curvelinear_test1(fig)
        curvelinear_test2(fig)

        plt.show()


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

   **Total running time of the script:** ( 0 minutes  1.024 seconds)


.. _sphx_glr_download_gallery_axisartist_demo_curvelinear_grid.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: demo_curvelinear_grid.py <demo_curvelinear_grid.py>`



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

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


.. only:: html

 .. rst-class:: sphx-glr-signature

    Keywords: matplotlib code example, codex, python plot, pyplot
    `Gallery generated by Sphinx-Gallery
    <https://sphinx-gallery.readthedocs.io>`_
