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| other:python:matplotlib_by_jyp [2021/02/26 12:45] – More gallery links updates jypeter | other:python:matplotlib_by_jyp [2023/10/26 10:39] (current) – [Useful matplotlib reference pages] jypeter |
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| ====== Working with matplotlib (JYP version) ====== | ====== Working with matplotlib (JYP version) ====== |
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| | <note tip>Note: [[https://matplotlib.org/cheatsheets/|Matplotlib cheatsheets]] ([[https://github.com/matplotlib/cheatsheets#cheatsheets-for-matplotlib-users|pdf version]])</note> |
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| **Summary**: there are lots of python libraries that you can use for plotting, but Matplotlib has become a //de facto// standard | **Summary**: there are lots of python libraries that you can use for plotting, but Matplotlib has become a //de facto// standard |
| * if you need several display windows at the same time, create several figures!\\ <code>win_1 = plt.figure() | * if you need several display windows at the same time, create several figures!\\ <code>win_1 = plt.figure() |
| win_2 = plt.figure()</code> | win_2 = plt.figure()</code> |
| * the [[http://matplotlib.org/faq/usage_faq.html#parts-of-a-figure|parts of a figure]] are usually positioned in //normalized coordinates//: ''(0, 0)'' is the bottom left of the figure, and ''(1, 1)'' is the top right | * the [[https://matplotlib.org/stable/gallery/showcase/anatomy.html|parts of a figure]] are usually positioned in //normalized coordinates//: ''(0, 0)'' is the bottom left of the figure, and ''(1, 1)'' is the top right |
| * You don't really specify the **page orientation** (//portrait// or //landscape//) of a plot. If you want a portrait plot, it's up to you to create a plot that will look higher than it is large. The idea is not to worry about this and just check the final resulting plot: create a plot, save it, display the resulting png/pdf and then adjust the creation script | * You don't really specify the **page orientation** (//portrait// or //landscape//) of a plot. If you want a portrait plot, it's up to you to create a plot that will look higher than it is large. The idea is not to worry about this and just check the final resulting plot: create a plot, save it, display the resulting png/pdf and then adjust the creation script |
| * If you do have an idea of the layout of what you want to plot, it may be easier to explicitly specify the figure size/ratio at creation time, and then try to //fill// the normalized coordinates space of the figure | * If you do have an idea of the layout of what you want to plot, it may be easier to explicitly specify the figure size/ratio at creation time, and then try to //fill// the normalized coordinates space of the figure |
| * The specified ''width'' and ''height'' are supposed to be in inches (1 inch = 2.54 cm) | * The specified ''width'' and ''height'' are supposed to be in inches (1 inch = 2.54 cm) |
| * ''my_page = plt.figure(figsize=(8.3, 11.7))'': create a figure that will theoretically fill an A4 size page in portrait mode (check [[https://www.papersizes.org/a-paper-sizes.htm|Dimensions Of A Series Paper Sizes]] if you need more details about standard paper sizes) | * ''my_page = plt.figure(figsize=(8.3, 11.7))'': create a figure that will theoretically fill an A4 size page in portrait mode (check [[https://www.papersizes.org/a-paper-sizes.htm|Dimensions Of A Series Paper Sizes]] if you need more details about standard paper sizes) |
| * a Matplotlib **//Axis//** is a **plot** inside a Figure... [[http://matplotlib.org/faq/usage_faq.html#parts-of-a-figure|More details]] | * a Matplotlib **//Axes//** (not to be confused with an //**axis**//) is a **(sub-)plot** inside a Figure... [[https://matplotlib.org/stable/api/axes_api.html|(much) More details]] |
| * reserve space for **one plot** that will use most of the available area of the figure/page: | * reserve space for **one plot** that will use most of the available area of the figure/page: |
| * ''my_plot = my_page.add_subplot(1, 1, 1)'' or ''my_plot = my_page.subplot**s**()'' | * ''my_plot = my_page.add_subplot(1, 1, 1)'' or ''my_plot = my_page.subplot**s**()'' |
| * The ''plot'' function will be faster for scatterplots where markers don't vary in size or color | * The ''plot'' function will be faster for scatterplots where markers don't vary in size or color |
| * [[https://matplotlib.org/api/_as_gen/matplotlib.axes.Axes.contourf.html|contour(...) and contourf(...)]]: draw contour lines and filled contours | * [[https://matplotlib.org/api/_as_gen/matplotlib.axes.Axes.contourf.html|contour(...) and contourf(...)]]: draw contour lines and filled contours |
| * **X and Y axes parameters** (see also [[https://matplotlib.org/examples/showcase/anatomy.html|Anatomy of a figure]]): | * **X and Y axes parameters** (see also [[https://matplotlib.org/stable/gallery/showcase/anatomy.html|Anatomy of a figure]]): |
| * **Axis range**: ''my_plot.set_xlim(x_leftmost_value, x_rightmost_value)'' | * **Axis range**: ''my_plot.set_xlim(x_leftmost_value, x_rightmost_value)'' |
| * Use the leftmost and rightmost values to specify the orientation of the axis (i.e the rightmost value can be smaller than the leftmost) | * Use the leftmost and rightmost values to specify the orientation of the axis (i.e the rightmost value can be smaller than the leftmost) |
| * [[https://stackoverflow.com/questions/35479508/cartopy-set-xlabel-set-ylabel-not-ticklabels|Trick source]] | * [[https://stackoverflow.com/questions/35479508/cartopy-set-xlabel-set-ylabel-not-ticklabels|Trick source]] |
| * Trick needs to be used with ''cartopy 0.17.0''\\ Remember to update/remove this information in the future | * Trick needs to be used with ''cartopy 0.17.0''\\ Remember to update/remove this information in the future |
| * Major (and minor) **tick marks location**: ''my_plot.set_xticks(x_ticks_values, minor=False)'' | * Major (and minor) **tick marks location**: ''my_plot.set_xticks(x_ticks_values, minor=False)'' ([[https://matplotlib.org/stable/api/_as_gen/matplotlib.axes.Axes.set_xticks.html|set_xticks]]) |
| * Use an empty list if you don't want tick marks: ''my_plot.set_xticks([])'' | * Use an empty list if you don't want tick marks: ''my_plot.set_xticks([])'' |
| * **Tick labels** (if you don't want the default values): ''my_plot.set_xticklabels(x_ticks_labels, minor=False, fontsize=ticklabels_fontsize)'' | * **Tick labels**: ''my_plot.set_xticklabels(x_tick_labels, minor=False, fontsize=ticklabels_fontsize)'' ([[https://matplotlib.org/stable/api/_as_gen/matplotlib.axes.Axes.set_xticklabels.html|set_xticklabels]]) |
| * ''x_ticks_labels'' is a list of strings that has the same length as ''x_ticks_values''. Use an empty string in the positions where you don't want a label | * If you do not specify labels, the //default labels// will just be the values specifying the ticks' location |
| | * ''x_tick_labels'' is a list of strings that has the same length as ''x_ticks_values''.\\ Use an empty string in the positions where you don't want a label |
| | * The default numerical labels may be too long, due to numerical approximations. You can try to explicitly round the values, or generate correct label strings from the values\\ <code>>>> x_tick_values = np.arange(0, 1, 0.2) |
| | >>> x_tick_values.tolist() |
| | [0.0, 0.2, 0.4, 0.6000000000000001, 0.8] |
| | >>> x_tick_values.round(decimals=1).tolist() |
| | [0.0, 0.2, 0.4, 0.6, 0.8] |
| | >>> x_tick_labels = [ '%.1f' % (t_val,) for t_val in x_tick_values ] |
| | >>> x_tick_labels |
| | ['0.0', '0.2', '0.4', '0.6', '0.8'] |
| | >>> x_tick_labels[0] = 'START' |
| | >>> x_tick_labels[-1] = 'END' |
| | >>> x_tick_labels |
| | ['START', '0.2', '0.4', '0.6', 'END'] |
| | </code> |
| | * You can also use fancy [[https://matplotlib.org/stable/gallery/ticks_and_spines/tick-formatters.html|tick formatters]] |
| * Many more options for ticks, labels, orientation, ... | * Many more options for ticks, labels, orientation, ... |
| * **Grid lines**: | * **Grid lines**: |
| * [[https://matplotlib.org/api/_as_gen/matplotlib.pyplot.plot.html|plot(...)]]: //fmt// (see documentation) or ''marker'' and ''markerfacecolor''/''mfc'' (and ''markerfacecoloralt''/''mfcalt'' for dual color markers), ''markersize'', ''markeredgewidth''/''mew'', ''markeredgecolor'' (use ''markeredgecolor='none''' if you don't want to plot the edge of the markers), ''fillstyle'' (''full'', ''None'', [[https://matplotlib.org/stable/gallery/lines_bars_and_markers/marker_reference.htm|other]]) | * [[https://matplotlib.org/api/_as_gen/matplotlib.pyplot.plot.html|plot(...)]]: //fmt// (see documentation) or ''marker'' and ''markerfacecolor''/''mfc'' (and ''markerfacecoloralt''/''mfcalt'' for dual color markers), ''markersize'', ''markeredgewidth''/''mew'', ''markeredgecolor'' (use ''markeredgecolor='none''' if you don't want to plot the edge of the markers), ''fillstyle'' (''full'', ''None'', [[https://matplotlib.org/stable/gallery/lines_bars_and_markers/marker_reference.htm|other]]) |
| * [[https://matplotlib.org/api/_as_gen/matplotlib.pyplot.scatter.html|scatter(...)]]: ''marker'' (marker type), ''c'' (color), ''s'' (size), ''linewidths'' (linewidth of the marker edges), ''edgecolors'' | * [[https://matplotlib.org/api/_as_gen/matplotlib.pyplot.scatter.html|scatter(...)]]: ''marker'' (marker type), ''c'' (color), ''s'' (size), ''linewidths'' (linewidth of the marker edges), ''edgecolors'' |
| * [[https://matplotlib.org/api/colors_api.html|colors]] and colormaps | * [[https://matplotlib.org/stable/api/colors_api.html|colors]] and colormaps |
| * [[https://matplotlib.org/stable/gallery/color/color_demo.html|color demo]] | * [[https://matplotlib.org/stable/gallery/color/color_demo.html|color demo]] |
| * [[https://matplotlib.org/examples/color/named_colors.html|named colors]] | * [[https://matplotlib.org/stable/gallery/color/named_colors.html#sphx-glr-gallery-color-named-colors-py|named colors]] |
| | * [[https://www.w3schools.com/colors/colors_picker.asp|HTML color picker]] and different ways of choosing colors |
| * Reverting the colors: add ''_r'' at the end of the colormap name | * Reverting the colors: add ''_r'' at the end of the colormap name |
| * Number of colors in the //my_cmap// colormap (usually 256): ''my_cmap.N'' | * Number of colors in the //my_cmap// colormap (usually 256): ''my_cmap.N'' |
| * ''my_cmap.set_over(color='k')'': color to be used for //high out-of-range values// **if** ''extend'' is specified and is //'both'// or //'max'//. Default color is ''my_cmap(my_cmap.N - 1)'' | * ''my_cmap.set_over(color='k')'': color to be used for //high out-of-range values// **if** ''extend'' is specified and is //'both'// or //'max'//. Default color is ''my_cmap(my_cmap.N - 1)'' |
| * ''my_cmap.set_under(color='k')'': color to be used for //low out-of-range values// **if** ''extend'' is specified and is //'both'// or //'min'//. Default color is ''my_cmap(0)'' | * ''my_cmap.set_under(color='k')'': color to be used for //low out-of-range values// **if** ''extend'' is specified and is //'both'// or //'min'//. Default color is ''my_cmap(0)'' |
| * [[https://matplotlib.org/api/_as_gen/matplotlib.figure.Figure.html#matplotlib.figure.Figure.colorbar|colorbar]] | * [[https://matplotlib.org/stable/api/figure_api.html#matplotlib.figure.Figure.colorbar|colorbar]] (see also the [[https://matplotlib.org/stable/api/colorbar_api.html|colorbar api]]) |
| * [[https://matplotlib.org/stable/gallery/subplots_axes_and_figures/colorbar_placement.html|Placing colorbars demo]] | * [[https://matplotlib.org/stable/gallery/subplots_axes_and_figures/colorbar_placement.html|Placing colorbars demo]] |
| * [[https://matplotlib.org/stable/gallery/images_contours_and_fields/contourf_demo.html|contourf + colorbar demo]] | * [[https://matplotlib.org/stable/gallery/images_contours_and_fields/contourf_demo.html|contourf + colorbar demo]] |
| | * Changing the font size of a colorbar (i.e. //changing [[https://matplotlib.org/stable/api/axes_api.html#ticks-and-tick-labels|ticks and tick labels]]//): |
| | * This can be done by manipulating the properties of the //Axes// where the colorbar is plotted\\ e.g. change the tick labels font size with\\ ''cb.ax.tick_params(labelsize='xx-large')'' (where ''cb'' is a //colorbar// object) |
| * [[https://matplotlib.org/api/_as_gen/matplotlib.pyplot.text.html|text(...)]] and [[https://matplotlib.org/tutorials/text/annotations.html|annotations]] | * [[https://matplotlib.org/api/_as_gen/matplotlib.pyplot.text.html|text(...)]] and [[https://matplotlib.org/tutorials/text/annotations.html|annotations]] |
| * Some titles: | * Some titles: |
| * [[https://matplotlib.org/stable/gallery/text_labels_and_annotations/titles_demo.html|Title and labels positions demo]] | * [[https://matplotlib.org/stable/gallery/text_labels_and_annotations/titles_demo.html|Title and labels positions demo]] |
| * ''fontsize'': size in points, or (better!) string specifying a relative size (''xx-small'', ''x-small'', ''small'', ''medium'', ''large'', ''x-large'', ''xx-large'') | * ''fontsize'': size in points, or (better!) string specifying a relative size (''xx-small'', ''x-small'', ''small'', ''medium'', ''large'', ''x-large'', ''xx-large'') |
| * [[https://matplotlib.org/api/text_api.html#matplotlib.text.Text|all the text properties]] | * [[https://matplotlib.org/stable/api/text_api.html|all the text properties]] |
| * [[https://matplotlib.org/api/pyplot_api.html#matplotlib.pyplot.legend|legend(...)]] ([[https://matplotlib.org/examples/pylab_examples/legend_demo3.html|legend demo]], [[https://matplotlib.org/users/legend_guide.html|advanced legend guide]]) | * [[https://matplotlib.org/stable/api/_as_gen/matplotlib.pyplot.legend.html|legend(...)]] ([[https://matplotlib.org/stable/gallery/text_labels_and_annotations/legend_demo.html|legend demo]], [[https://matplotlib.org/stable/tutorials/intermediate/legend_guide.html|advanced legend guide]]) |
| * The legend will //show// the lines (or other objects) that were associated with a //label// with the ''label='' keyword when creating/updating a plot | * The legend will //show// the lines (or other objects) that were associated with a //label// with the ''label='' keyword when creating/updating a plot |
| * If there are some elements of a plot that you do not want to associate with a legend (e.g. there are several lines with the same color and markers, but you want to plot the legend only once), do not specify a ''label='' keyword for these elements, or add a ''_'' at the front of the label strings | * If there are some elements of a plot that you do not want to associate with a legend (e.g. there are several lines with the same color and markers, but you want to plot the legend only once), do not specify a ''label='' keyword for these elements, or add a ''_'' at the front of the label strings |
| [[https://stackoverflow.com/questions/9797520/masking-part-of-a-contourf-plot-in-matplotlib|trick source]] | [[https://stackoverflow.com/questions/9797520/masking-part-of-a-contourf-plot-in-matplotlib|trick source]] |
| |
| | ===== Unsorted matplotlib stuff ===== |
| | |
| | Some useful notes and links that cannot be placed (yet) in a section of the main page |
| | |
| | ==== Plotting arcs (segments of ellipses) ==== |
| | |
| | * [[https://matplotlib.org/stable/api/_as_gen/matplotlib.patches.Arc.html|Offical patches.Arc documentation]] |
| | * A nice [[https://stackoverflow.com/questions/54849976/can-someone-explain-the-different-parameters-in-matplotlib-patches-arc|ellipses and arcs tutorial]] on stackoverflow |
| | |
| | ==== Using hatches with contourf ==== |
| | |
| | * [[https://matplotlib.org/stable/gallery/shapes_and_collections/hatch_style_reference.html|Hatch style reference]] |
| | * [[https://matplotlib.org/stable/gallery/shapes_and_collections/hatch_demo.html|Hatch demo]] |
| | * [[https://matplotlib.org/stable/gallery/images_contours_and_fields/contourf_hatching.html|Contourf hatching]] |
| | * //Collections// trick for [[https://fantashit.com/hatching-color-in-contourf-function/|changing the colors of hatches]] |
| |
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