.. 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_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. .. image:: /gallery/axisartist/images/sphx_glr_demo_curvelinear_grid_001.png :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() .. _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 ` .. container:: sphx-glr-download sphx-glr-download-jupyter :download:`Download Jupyter notebook: demo_curvelinear_grid.ipynb ` .. only:: html .. rst-class:: sphx-glr-signature Keywords: matplotlib code example, codex, python plot, pyplot `Gallery generated by Sphinx-Gallery `_