Step plot-Python(matplot)

Step Plot is a Matplotlib graph that represents data in a stepped fashion. Step plots work best for discrete data rather than continuous data or when values stay fixed at specific intervals. For example, digital signal processing, discrete data visualization, and histogram-like graphing often rely on step plots.

The way to draw a Step Plot in Matplotlib is to use the plt.step() function.

 Basic Usage

The plt.step() function takes in x and y data and plots a staircase graph.

plt.step(x, y, where='pre', label=None, color=None, linestyle='-', linewidth=2, marker=None)

• x: x-axis data.
• y: y-axis data.
• where: Specifies the shape of the staircase (‘pre’, ‘post’, ‘mid’).
• label: Label to be displayed in the legend.
• color: Line color.
• linestyle: Line style (‘-‘, ‘–‘, ‘:’, ‘-.’).
• linewidth: Line thickness.
• marker: show markers on the data points.

where parameter

The where parameter determines the shape of the staircase. The main options are

plt.step(x, y, where='pre', label='pre (default)')
plt.step(x, y, where='post', label='post')
plt.step(x, y, where='mid', label='mid')

• ‘pre’ (default): Draws a horizontal line from each x value to the previous value.
• ‘post’: Draw a horizontal line from each x value to the next value.
• ‘mid’: Draws a horizontal line from the middle of each x value.

Step plot Code

import matplotlib.pyplot as plt

x = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
y = [10, 20, 15, 25, 20, 15, 5, 20, 23, 30]

plt.step(x, y, where='mid')
plt.xlabel('X-axis')
plt.ylabel('Y-axis')
plt.title('Step Plot Example')
plt.show()

Advantages of Step Plots

• Great for representing discrete data: Ideal for non-continuous data where values are held in specific bins.
• Visual clarity: The staircase shape makes changes in data clear and easy to interpret.
• Flexible: The where parameter lets you control the position of steps, allowing for customization.

Cons of Step Plots

• Not suitable for continuous data: Step plots don’t work well for smooth, continuous datasets.
• Can be confusing with complex data: When dealing with a large number of data points, step plots can become cluttered and harder to read.

Use Cases for Step Plots

• Digital signal processing: Ideal for visualizing changes in digital signals.
• Discrete data visualization: Works well for representing discrete datasets, such as daily sales.
• Histogram replacement: Provides a histogram-like representation without using bars.

Step plots are powerful for discrete data but should be used carefully to avoid confusion with complex datasets.

Step Plot vs Line Plot

Example : Step Plot vs Line Plot

x = np.array([1, 2, 3, 4, 5])
y = np.array([1, 3, 2, 4, 3])

plt.plot(x, y, label='Line Plot', marker='o')
plt.step(x, y, where='pre', label='Step Plot', linestyle='--')

plt.title('Step Plot vs Line Plot')
plt.xlabel('X-axis')
plt.ylabel('Y-axis')
plt.legend()
plt.grid(True)
plt.show()

정리

• Step Plot은 이산 데이터를 계단식으로 표현하는 데 유용합니다.
• where 파라미터를 통해 계단의 형태를 조절할 수 있습니다.
• 선 스타일, 색상, 마커 등을 사용하여 그래프를 꾸밀 수 있습니다.
• 연속 데이터보다는 이산 데이터에 더 적합합니다.

Step Plot을 적절히 활용하면 데이터의 변화를 명확하고 직관적으로 표현할 수 있습니다!