How to draw a vertical line on a heatmap drawn with Python seaborn
Introduction
Heatmaps are often displayed with spatial coordinates on the horizontal and vertical axes. In addition to that, there are times when you want to take the horizontal axis as time, such as drawing the result of STFT (Short-Time Fourier Transform) where the horizontal axis is time and the vertical axis is frequency. At that time, I wanted to put a vertical line anywhere in the analysis to get a picture of when the event fired. I couldn't find a way to draw a vertical line with seaborn, so I'll leave it as a memorandum.
Target
Put a vertical line in the heatmap
Method
It seems that you can enter it normally using axvline. So I actually tried it.
vline_heatmap.py
import matplotlib.pyplot as plt
import numpy as np
import seaborn as sns
#Sample array creation
arr = np.random.rand(20, 20)
#Heat map display (left side)
fig, (ax1, ax2) = plt.subplots(1, 2)
sns.heatmap(arr, vmin=0, vmax=5, cmap="jet", ax=ax1)
#Display with vertical lines on the heat map (right side)
sns.heatmap(arr, vmin=0, vmax=5, cmap="jet", ax=ax2)
ax2.axvline(x=4, linewidth=2, color="w")
#drawing
plt.show()
Drawing result
The drawing result with no vertical line on the left and with vertical line on the right is shown.
Opinions etc.
Please write in the comments of this article or send to the following email address (change [at] to @).
akira.kashihara[at]hotmail.com
reference
After investigating and tracing the vertical lines with reference to article 1, I came across article 2 and tried it. If you have any other articles that you are writing directly, please let me know.
- Draw a horizontal line at any position on the y-axis in the graph using seaborn
- matplotlib.pyplot.axvline
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