I copied the code for adding legend via proxy artists from matplotlib's documentation but it doesn't work. I also tried the rest in matplotlib's legends guide but nothing works. I guess it's because the element is a shapely feature which ax.legend() somehow doesn't recognize.
Code
bounds = [116.9283371, 126.90534668, 4.58693981, 21.07014084]
stamen_terrain = cimgt.Stamen('terrain-background')
fault_line = ShapelyFeature(Reader('faultLines.shp').geometries(), ccrs.epsg(32651),
linewidth=1, edgecolor='black', facecolor='none') # geometry is multilinestring
fig = plt.figure(figsize=(15,10))
ax = fig.add_subplot(1, 1, 1, projection=ccrs.PlateCarree())
ax.set_extent(bounds)
ax.add_image(stamen_terrain, 8)
a = ax.add_feature(fault_line, zorder=1, label='test')
ax.legend([a], loc='lower left', fancybox=True) #plt.legend() has the same result
plt.show()
Result
When copying the matplotlib example, you omitted the actual "proxy" artist line!
red_patch = mpatches.Patch(color='red', label='The red data')
plt.legend(handles=[red_patch])
That red_patch is the proxy artist. You have to create a dummy artist to pass to legend(). Your code as written is still passing the unrecognized Shapely feature.
It's tedious, but the relevant code would be something like:
fault_line = ShapelyFeature(Reader('faultLines.shp').geometries(), ccrs.epsg(32651), linewidth=1, edgecolor='black', facecolor='none')
ax.add_feature(fault_line, zorder=1)
# Now make a dummy object that looks as similar as possible
import matplotlib.patches as mpatches
proxy_artist = mpatches.Rectangle((0, 0), 1, 0.1, linewidth=1, edgecolor='black', facecolor='none')
# And manually add the labels here
ax.legend([proxy_artist], ['test'], loc='lower left', fancybox=True)
Here I just used a Rectangle, but depending on the feature, you can use various supported matplotlib "artists".
Related
I have created a plot, which is working just fine.
But I really want to change its shape to a circle.
This is my current plotting code:
import matplotlib.pyplot as plt
fig = plt.figure(figsize=(5,5), dpi=300)
ax = fig.add_axes([0,0,1,1])
ax.plot(30, 80, marker="o", markersize=20, markeredgecolor="#ed6033", markerfacecolor="#ed6033")
ax.spines['left'].set_position('center')
ax.spines['bottom'].set_position('center')
ax.spines['right'].set_color('none')
ax.spines['top'].set_color('none')
ax.xaxis.set_ticks_position('bottom')
ax.yaxis.set_ticks_position('left')
ax.set_facecolor('#8cc9e2')
ax.margins(0.1)
plt.setp(ax.get_xticklabels()[4], visible=False)
plt.xlim(10, 90)
plt.ylim(10, 90)
plt.grid(color='white')
plt.show()
and this is the output I get:
eventually, this is my desired output:
You can clip the path of artists including the background patch using the path of another artist.
Add this snippet before the plt.show() call:
clip_path = plt.Circle(
(0.5, 0.5), 0.5, transform=ax.transAxes, # circle coordinates defined in axes fractions
fill=None, linewidth=0 # makes circle invisible
)
ax.add_patch(clip_path)
ax.patch.set_clip_path(clip_path)
I would like to have a single legend that nicely fits on top of both the subplots (doesn't necessarily need to span the entire width of the plots, but needs to be outside the plot). I know you can work with bbox_to_anchor() but somehow this doesn't seem to work nicely. It always moves one subplot away.
fig, ax = plt.subplots(1, 2)
sns.barplot(x="day", y="total_bill", hue="sex", data=tips, ax = ax[0])
ax[0].legend_.remove()
sns.barplot(x="day", y="total_bill", hue="sex", data=tips, ax = ax[1])
sns.move_legend(ax[1], loc = "center", bbox_to_anchor=(-0.5, 1.1), ncol=2, title=None, frameon=False)
fig.tight_layout()
There are a couple of ways that I would approach closing the gap.
1: Use a sns.catplot:
This potentially requires doubling your data, though if you're plotting different variables in each subplot you may be able to melt your data
import pandas as pd
import seaborn as sns
# Load the dataset twice
tips_a = sns.load_dataset("tips")
tips_b = sns.load_dataset("tips")
# Add a dummy facet variable
tips_a["col"] = "A"
tips_b["col"] = "B"
# Concat them
tips = pd.concat([tips_a, tips_b])
# Use the dummy variable for the `col` param
g = sns.catplot(x="day", y="total_bill", hue="sex", data=tips, kind="bar", col="col")
# Remove the titles and move the legend
g.set_titles("")
sns.move_legend(g, loc="upper center", ncol=2, title=None, frameon=False)
2: autoscale the axes
This still requires a little bit of bbox_to_anchor fiddling and you probably want to change the right y-axis label (and ticks/ticklabels).
import matplotlib.pyplot as plt
import seaborn as sns
fig, ax = plt.subplots(1, 2, figsize=(7, 4))
sns.barplot(x="day", y="total_bill", hue="sex", data=tips, ax=ax[0])
ax[0].legend_.remove()
sns.barplot(x="day", y="total_bill", hue="sex", data=tips, ax=ax[1])
sns.move_legend(
ax[1],
loc="upper center",
bbox_to_anchor=(-0.1, 1.1),
ncol=2,
title=None,
frameon=False,
)
ax[0].autoscale()
ax[1].autoscale()
I am trying to understand the underlying concepts of matplotlib, especially Axes and Figure. Therefore I am trying to plot two scatters and then remove any superfluous space (the red one below) by accessing different APIs & objects in the hierarchy.
Yet I fail to understand where the remaining red space is coming from. This is the code:
# Random data
df = pd.DataFrame(np.random.randint(0,100,size=(100, 2)), columns=list('AB'))
# Create a single Axes and preconfigure the figure with red facecolor.
# Then plot a scatter
fig, axes = plt.subplots(nrows=1, ncols=2, figsize=(10,5), facecolor='r')
ax1 = df.plot(kind='scatter', x='A', y='B', ax=axes[0])
ax2 = df.plot(kind='scatter', x='B', y='A', ax=axes[1])
# Remove except the scatter
for a in [ax1, ax2]:
a.set_xlabel(''), a.set_ylabel('') # Remove x and y labels
for loc in ['left', 'right', 'bottom', 'top']:
a.spines[loc].set_visible(False) # Remove spines
a.set_xticks([], []), a.set_yticks([], []) # Remove ticks
a.set_xmargin(0), a.set_ymargin(0) # No margin beyond outer values
# On figure-level we can make it more tight
fig.tight_layout()
It produces the following figure:
I saw that there is something like..
a.set_axis_off()
.. but this doesn't seem to be the right solution. Somewhere there seems to be some kind of padding that remains. It doesn't look like it's from some X/Y axis as it's the same for all four edges in both subplots.
Any help appreciated.
Solution
Two things are needed:
First we need to initialize the Figure with frameon=False:
fig, axes = plt.subplots(
// ...
frameon=False)
The space between the subplots can be removed using the subplot layout:
plt.subplots_adjust(wspace=.0, hspace=.0)
For the finest level of layout control, you can position your axes manually instead of relying on matplotlib to do it for you. There are a couple of ways of doing this.
One option is Axes.set_position
# Random data
df = pd.DataFrame(np.random.randint(0,100,size=(100, 2)), columns=list('AB'))
# Create a pair of Axes and preconfigure the figure with red facecolor.
# Then plot a scatter
fig, axes = plt.subplots(1, 2, figsize=(10, 5), facecolor='r')
df.plot(kind='scatter', x='A', y='B', ax=axes[0]).set_position([0, 0, 0.5, 1])
df.plot(kind='scatter', x='B', y='A', ax=axes[1]).set_position([0, 0.5, 0.5, 1])
You could also use the old-fashioned Figure.add_axes method:
# Random data
df = pd.DataFrame(np.random.randint(0,100,size=(100, 2)), columns=list('AB'))
# Create a pair of Axes and preconfigure the figure with red facecolor.
# Then plot a scatter
fig = plt.figure(figsize=(10, 5), facecolor='r')
df.plot(kind='scatter', x='A', y='B', ax=fig.add_axes([0, 0, 0.5, 1]))
df.plot(kind='scatter', x='B', y='A', ax=fig.add_axes([0, 0.5, 0.5, 1]))
I would like to generate a centered figure legend for subplot(s), for which there is a single label. For my actual use case, the number of subplot(s) is greater than or equal to one; it's possible to have a 2x2 grid of subplots and I would like to use the figure-legend instead of using ax.legend(...) since the same single label entry will apply to each/every subplot.
As a brief and simplified example, consider the code just below:
import numpy as np
import matplotlib.pyplot as plt
x = np.arange(10)
y = np.sin(x)
fig, ax = plt.subplots()
ax.plot(x, y, color='orange', label='$f(x) = sin(x)$')
fig.subplots_adjust(bottom=0.15)
fig.legend(mode='expand', loc='lower center')
plt.show()
plt.close(fig)
This code will generate the figure seen below:
I would like to use the mode='expand' kwarg to make the legend span the entire width of the subplot(s); however, doing so prevents the label from being centered. As an example, removing this kwarg from the code outputs the following figure.
Is there a way to use both mode='expand' and also have the label be centered (since there is only one label)?
EDIT:
I've tried using the bbox_to_anchor kwargs (as suggested in the docs) as an alternative to mode='expand', but this doesn't work either. One can switch out the fig.legend(...) line for the line below to test for yourself.
fig.legend(loc='lower center', bbox_to_anchor=(0, 0, 1, 0.5))
The handles and labels are flush against the left side of the legend. There is no mechanism to allow for aligning them.
A workaround could be to use 3 columns of legend handles and fill the first and third with a transparent handle.
import numpy as np
import matplotlib.pyplot as plt
x = np.arange(10)
y = np.sin(x)
fig, ax = plt.subplots()
fig.subplots_adjust(bottom=0.15)
line, = ax.plot(x, y, color='orange', label='$f(x) = sin(x)$')
proxy = plt.Rectangle((0,0),1,1, alpha=0)
fig.legend(handles=[proxy, line, proxy], mode='expand', loc='lower center', ncol=3)
plt.show()
I want to completely remove white space around my axes during active plot (not save_fig as others asked).
Here we cannot use bbox_inches='tight'. I can use tight_layout(pad=0).
When axis is on, it works fine, it shows all the ticks and x-y labels.
However, in some cases, I set the axis off. What I expected is to see the contents expand to fill up the empty space where the axes are. However, this does not work. It still keep the padding as there are still x-y labels and axes.
How can I remove the white space of invisible axes objects?
edit:
I am aware that I can use ax.set_yticks([]) and ax.set_xticks([]) to turn those off. But this is clumsy, I have to remember the the ticks before I clear them. And if I remove-then-add those ticks. The ticks cannot automatically update any more.
I wonder is there any more straightforward way to do this?
We can still see there is a small border spacing even after removing all ticks. If someone can come up a way to remove that too. It will be fantastic.
I would also like to keep the title if there is one. Thus the hard-coded ax.set_position([0,0,1,x]) is not very good for this usage. Surely we can still try to get the top spacing when there is a title, but if someone can provide a more direct/simple way to handle this, it will be preferred.
Example code:
def demo_tight_layout(w=10, h=6, axisoff=False, removeticks=False):
fig,ax = plt.subplots()
fig.set_facecolor((0.8, 0.8, 0.8))
rect = patches.Rectangle((-w/2, -h/2), w, h, color='#00ffff', alpha=0.5)
ax.add_patch(rect)
ax.plot([-w/2,w/2], [-h/2,h/2])
ax.plot([-w/2,w/2], [h/2,-h/2])
ax.set_ylabel("ylabel")
ax.margins(0)
_texts = []
if axisoff:
ax.set_axis_off()
_texts.append("axisoff")
if removeticks:
ax.set_xticks([])
ax.set_yticks([])
ax.set_ylabel("")
_texts.append("removeticks")
fig.text(0.5, 0.6, " ".join(_texts))
fig.tight_layout(pad=0)
plt.show()
return fig, ax, text
You may adjust the subplot parameters depending on whether you turned the axis off or not.
import matplotlib.pyplot as plt
from matplotlib import patches
def demo_tight_layout(w=10, h=6, axisoff=False):
fig,ax = plt.subplots()
fig.set_facecolor((0.8, 0.8, 0.8))
rect = patches.Rectangle((-w/2, -h/2), w, h, color='#00ffff', alpha=0.5)
ax.add_patch(rect)
ax.plot([-w/2,w/2], [-h/2,h/2])
ax.plot([-w/2,w/2], [h/2,-h/2])
ax.set_ylabel("ylabel")
ax.margins(0)
_texts = []
fig.tight_layout()
if axisoff:
ax.set_axis_off()
_texts.append("axisoff")
params = dict(bottom=0, left=0, right=1)
if ax.get_title() == "":
params.update(top=1)
fig.subplots_adjust(**params)
fig.text(0.5, 0.6, " ".join(_texts))
plt.show()
Now demo_tight_layout(axisoff=True) produces
and demo_tight_layout(axisoff=False) produces
You need to set the axes position to fill the figure. If you create your figure and plot with
import matplotlib.pyplot as plt
fig = plt.figure()
ax = fig.gca()
ax.plot(some_x_data, some_y_data)
you need to add the following line to fill the figure with the axes:
ax.set_position([0, 0, 1, 1], which='both')
This sets the axes location relative to the figure size in the following way:
[left, bottom, width, height]
So to completely fill the figure use [0, 0, 1, 1] as shown above.
So taking your code, it should look like this (using fill_figure bool to check):
def demo_tight_layout(w=10, h=6, axisoff=False, removeticks=False, fill_figure=False):
fig,ax = plt.subplots()
fig.set_facecolor((0.8, 0.8, 0.8))
rect = patches.Rectangle((-w/2, -h/2), w, h, color='#00ffff', alpha=0.5)
ax.add_patch(rect)
ax.plot([-w/2,w/2], [-h/2,h/2])
ax.plot([-w/2,w/2], [h/2,-h/2])
ax.set_ylabel("ylabel")
ax.margins(0)
_texts = []
if axisoff:
ax.set_axis_off()
_texts.append("axisoff")
if removeticks:
ax.set_xticks([])
ax.set_yticks([])
ax.set_ylabel("")
_texts.append("removeticks")
fig.text(0.5, 0.6, " ".join(_texts))
fig.tight_layout(pad=0)
if fill_figure:
ax.set_position([0, 0, 1, 1], which='both')
plt.show()
return fig, ax, text
ax.set_position needs to be after fig.tight_layout.
If a figure title is needed, there is no direct way to do it. This unluckily can't be avoided. You need to adapt the height parameters manually so that the title fits in the figure, for example with:
ax.set_position([0, 0, 1, .9], which='both')