Matplotlib Plot DPI

Matplotlib is a Python library used for creating static, animated, and interactive visualizations in Python. One of the important aspects of visualizations is the resolution of the output image. This is where the concept of DPI (Dots Per Inch) plays a crucial role.

What is DPI?

DPI stands for Dots Per Inch. It is a measure of the number of individual dots that can be placed in a line within the span of 1 inch. DPI is typically used to describe the resolution of an image or print. The higher the DPI, the more dots that can fit within the same area, resulting in a higher resolution image or print.

In the context of Matplotlib, DPI defines the resolution of the image being created from a plot. When a plot is created, it is first rendered in memory as an image, and then it can be saved to disk or displayed on screen. The DPI setting controls the resolution of this rendered image.

Matplotlib Plot DPI

Matplotlib provides an option to set the DPI for a plot using the dpi parameter. The default value of dpi is 100. A higher value of dpi will result in a higher-quality image, but the file size will also be larger. A lower value of dpi will result in a lower-quality image, but the file size will be smaller.

Here is a code snippet demonstrating the use of dpi to create a plot with a resolution of 300 DPI:

import matplotlib.pyplot as plt

# Create some data
x = [1, 2, 3, 4, 5]
y = [10, 8, 6, 4, 2]

# Create a plot
fig, ax = plt.subplots()
ax.plot(x, y)

# Set the DPI
fig.set_dpi(300)

# Save the plot
fig.savefig('my_plot_300dpi.png')

In this example, we first create some data for our plot. Then, we create a plot using ax.plot(). We then set the DPI using fig.set_dpi(). Finally, we save the plot to disk using fig.savefig(). The resulting plot will have a resolution of 300 DPI.

Conclusion

DPI is an important aspect of visualizations, as it controls the resolution of the output image. Matplotlib provides an option to set the DPI using the dpi parameter. By default, the value of dpi is 100. Setting a higher value of dpi will result in a higher-quality image, but the file size will be larger. Setting a lower value of dpi will result in a lower-quality image, but the file size will be smaller.