.. DO NOT EDIT. .. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY. .. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE: .. "gallery/XY/NCL_xy_4.py" .. LINE NUMBERS ARE GIVEN BELOW. .. only:: html .. note:: :class: sphx-glr-download-link-note :ref:`Go to the end ` to download the full example code. .. rst-class:: sphx-glr-example-title .. _sphx_glr_gallery_XY_NCL_xy_4.py: NCL_xy_4.py =============== This script illustrates the following concepts: - Drawing a scatter plot - Changing the markers in an XY plot - Changing the marker color in an XY plot - Changing the marker size in an XY plot - Creating your own markers for an XY plot - Drawing a legend See following URLs to see the reproduced NCL plot & script: - Original NCL script: https://www.ncl.ucar.edu/Applications/Scripts/xy_4.ncl - Original NCL plots: https://www.ncl.ucar.edu/Applications/Images/xy_4_1_lg.png and https://www.ncl.ucar.edu/Applications/Images/xy_4_2_lg.png Ways of specifying marks: - matplotlib.markers has an extensive `list `_ of predefined markers - Mathematical symbols described `here `_ can be used - Unicode characters - If you still cannot find the symbol you are looking for, a custom made `Path `_ instance can be used to draw your own marker .. GENERATED FROM PYTHON SOURCE LINES 25-26 Import packages: .. GENERATED FROM PYTHON SOURCE LINES 26-36 .. code-block:: Python import numpy as np import xarray as xr import matplotlib.pyplot as plt import matplotlib.path as mpath import math import geocat.datafiles as gdf import geocat.viz as gv .. GENERATED FROM PYTHON SOURCE LINES 37-38 Read in data: .. GENERATED FROM PYTHON SOURCE LINES 38-46 .. code-block:: Python # Open a netCDF data file using xarray default engine and load the data into xarrays ds = xr.open_dataset(gdf.get('netcdf_files/AtmJan360_xy_4.nc'), decode_times=False) # Extract a slice of the data ds = ds['T'] t = ds.isel(lev=0, lat=32, lon=29, drop=True) .. GENERATED FROM PYTHON SOURCE LINES 47-48 Plot with standard markers: .. GENERATED FROM PYTHON SOURCE LINES 48-76 .. code-block:: Python plt.figure(figsize=(8, 8)) ax = plt.axes() plt.scatter(t.time, t.data, color='red') # Use geocat.viz.util convenience function to set titles and labels gv.set_titles_and_labels( ax, maintitle="Scatter Plot", xlabel=t['time'].long_name, ylabel=t.long_name ) # Use geocat.viz.util convenience function to add minor and major tick lines gv.add_major_minor_ticks(ax, x_minor_per_major=5, y_minor_per_major=4, labelsize=14) # Calculate xlim by rounding the min value down and the max value up to a # multiple of 5 xmin = 5 * math.floor(t.time.min().data / 5) xmax = 5 * math.ceil(t.time.max().data / 5) gv.set_axes_limits_and_ticks( ax, xlim=(xmin, xmax), ylim=(220.0, 232.0), xticklabels=[' ', 131160, ' ', 131170, ' ', 131180, ' ', 131190], yticklabels=np.arange(220.0, 233.0, 2.0), ) plt.show() .. image-sg:: /gallery/XY/images/sphx_glr_NCL_xy_4_001.png :alt: Scatter Plot :srcset: /gallery/XY/images/sphx_glr_NCL_xy_4_001.png :class: sphx-glr-single-img .. rst-class:: sphx-glr-script-out .. code-block:: none /home/docs/checkouts/readthedocs.org/user_builds/geocat-examples/conda/latest/lib/python3.14/site-packages/geocat/viz/util.py:679: UserWarning: set_ticklabels() should only be used with a fixed number of ticks, i.e. after set_ticks() or using a FixedLocator. Otherwise, ticks may be mislabeled. ax.set_xticklabels(xticklabels) /home/docs/checkouts/readthedocs.org/user_builds/geocat-examples/conda/latest/lib/python3.14/site-packages/geocat/viz/util.py:682: UserWarning: set_ticklabels() should only be used with a fixed number of ticks, i.e. after set_ticks() or using a FixedLocator. Otherwise, ticks may be mislabeled. ax.set_yticklabels(yticklabels) .. GENERATED FROM PYTHON SOURCE LINES 77-78 Plot with custom markers: .. GENERATED FROM PYTHON SOURCE LINES 78-134 .. code-block:: Python plt.figure(figsize=(8, 8)) ax = plt.axes() # Divide the data into arbitrary sections so each can be drawn with a different # type of marker data1 = t.data[0:8] time1 = t.time[0:8] data2 = t.data[8:16] time2 = t.time[8:16] data3 = t.data[16:24] time3 = t.time[16:24] data4 = t.data[24:] time4 = t.time[24:] # marker='s' creates a square. This is from matplotlib.markers # This is not to be confused with the kwarg `s` which sets the marker size plt.scatter(time1, data1, color='blue', marker='s', label='matplotlib.markers') # Use a mathematical symbol for a marker plt.scatter( time2, data2, color='green', marker=r'$\Omega$', s=100, label='mathematical symbol' ) # Unicode symbol marker plt.scatter( time3, data3, color='black', marker='$\u2608$', s=100, label='unicode symbol' ) # Create custom path for marker verts = [(-0.5, -0.5), (-0.5, 0.5), (0, 0), (0.5, 0.5), (0.5, -0.5), (0, 0)] path = mpath.Path(verts) plt.scatter(time4, data4, color='red', marker=path, s=100, label='custom path') # Add legend plt.legend() # Use geocat.viz.util convenience function to set titles and labels gv.set_titles_and_labels( ax, maintitle="Make your own marker", xlabel=t['time'].long_name, ylabel=t.long_name ) # Use geocat.viz.util convenience function to add minor and major tick lines gv.add_major_minor_ticks(ax, x_minor_per_major=5, y_minor_per_major=4, labelsize=14) gv.set_axes_limits_and_ticks( ax, xlim=(xmin, xmax), ylim=(220.0, 232.0), xticklabels=[' ', 131160, ' ', 131170, ' ', 131180, ' ', 131190], yticklabels=np.arange(220.0, 233.0, 2.0), ) plt.show() .. image-sg:: /gallery/XY/images/sphx_glr_NCL_xy_4_002.png :alt: Make your own marker :srcset: /gallery/XY/images/sphx_glr_NCL_xy_4_002.png :class: sphx-glr-single-img .. rst-class:: sphx-glr-script-out .. code-block:: none /home/docs/checkouts/readthedocs.org/user_builds/geocat-examples/conda/latest/lib/python3.14/site-packages/geocat/viz/util.py:679: UserWarning: set_ticklabels() should only be used with a fixed number of ticks, i.e. after set_ticks() or using a FixedLocator. Otherwise, ticks may be mislabeled. ax.set_xticklabels(xticklabels) /home/docs/checkouts/readthedocs.org/user_builds/geocat-examples/conda/latest/lib/python3.14/site-packages/geocat/viz/util.py:682: UserWarning: set_ticklabels() should only be used with a fixed number of ticks, i.e. after set_ticks() or using a FixedLocator. Otherwise, ticks may be mislabeled. ax.set_yticklabels(yticklabels) .. rst-class:: sphx-glr-timing **Total running time of the script:** (0 minutes 1.173 seconds) .. _sphx_glr_download_gallery_XY_NCL_xy_4.py: .. only:: html .. container:: sphx-glr-footer sphx-glr-footer-example .. container:: sphx-glr-download sphx-glr-download-jupyter :download:`Download Jupyter notebook: NCL_xy_4.ipynb ` .. container:: sphx-glr-download sphx-glr-download-python :download:`Download Python source code: NCL_xy_4.py ` .. container:: sphx-glr-download sphx-glr-download-zip :download:`Download zipped: NCL_xy_4.zip ` .. only:: html .. rst-class:: sphx-glr-signature `Gallery generated by Sphinx-Gallery `_