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ViewsHow to set legend marker size and alpha?
I have a seaborn scatter plot (lmplot) with over 10K points. In order to perceive all the data, it works better when the plot size is larger (making the markers relatively small) and the alpha on the markers is low. However, this makes the markers on the legend difficult to distinguish. How does one set the marker size and marker alpha in Seaborn?
I see that g._legend has a markersize attribute, but directly setting it doesn't do anything.
Example
import numpy as np
import pandas as pd
import seaborn as sns
n_group = 4000
pos = np.concatenate((np.random.randn(n_group,2) + np.array([-1,-1]),
np.random.randn(n_group,2) + np.array([0.2, 1.5]),
np.random.randn(n_group,2) + np.array([0.6, -1.8])))
df = pd.DataFrame({"x": pos[:,0], "y": pos[:, 1],
"label": np.repeat(range(3), n_group)})
g = sns.lmplot("x", "y", df, hue = "label", fit_reg = False,
size = 8, scatter_kws = {"alpha": 0.1})
g._legend.set_title("Clusters")
·
Santiago Trujillo
2 answers
Answer question0
You can do this by setting the alpha values of the legend markers themselves. You can also use _sizes to set the marker sizes in the same for loop:
n_group = 4000
pos = np.concatenate((np.random.randn(n_group,2) + np.array([-1,-1]),
np.random.randn(n_group,2) + np.array([0.2, 1.5]),
np.random.randn(n_group,2) + np.array([0.6, -1.8])))
df = pd.DataFrame({"x": pos[:,0], "y": pos[:, 1],
"label": np.repeat(range(3), n_group)})
g = sns.lmplot("x", "y", df, hue = "label", fit_reg = False,
size = 8, scatter_kws = {"alpha": 0.1})
g._legend.set_title("Clusters")
for lh in g._legend.legendHandles:
lh.set_alpha(1)
lh._sizes = [50]
# You can also use lh.set_sizes([50])
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Santiago Trujillo
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the above did not work for me in a seaborn lineplot. This did:
g = sns.lineplot(data=df, x='X', y='Y', hue='HUE', ci=False, style='STYLE',
markers=True, ms=16, dashes=False)
#get legend and change stuff
handles, lables = g.get_legend_handles_labels()
for h in handles:
h.set_markersize(10)
# replace legend using handles and labels from above
lgnd = plt.legend(handles, lables, bbox_to_anchor=(1.02, 1), loc='upper left', borderaxespad=0, title='TITLE')
·
Santiago Trujillo
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