Sankey charts are a powerful visualization tool that can help you to effectively map flows between different nodes. These charts are particularly useful when you need to represent large amounts of directional data, making it easy to identify patterns and trends within the data.
In this article, we’ll explore how to create Sankey charts using popular data visualization libraries such as Matplotlib, Plotly, and D3.js. We’ll also discuss the various applications of Sankey charts, and provide some tips for effectively using them in your own data visualization projects.
Creating Sankey Charts with Matplotlib
Matplotlib is a popular Python library for creating a wide range of visualizations, including Sankey charts. The Sankey class in Matplotlib provides an easy-to-use interface for creating these charts. Here’s an example of how to create a simple Sankey chart using Matplotlib:
“`
from matplotlib.gridspec import GridSpec
from matplotlib.sankey import Sankey
import matplotlib.pyplot as plt
Set up the grid for the chart
gs = GridSpec(2, 3)
Create the chart
sankey = Sankey(fig=plt.figure(), axis=plt.subplot(gs[0, :-1]),
connections=[(0, 1, 1.0)],
nodes=[{‘name’: ‘Node A’, ‘x’: 0.5, ‘y’: 1.5, ‘text’: ‘Node A’},
{‘name’: ‘Node B’, ‘x’: 2.0, ‘y’: 1.5, ‘text’: ‘Node B’}])
Add elements to the chart
sankey.add流(源, 目标, 流量, 原始/百分比, 颜色)
sankey.finish()
Set the layout of the chart
ax.settitle(“Example Sankey Chart”)
ax.setxlim(0, 4)
ax.set_ylim(0, 3)
Show the chart
plt.show()
“`
In this example, the Sankey chart is created using a simple grid layout, with two nodes and a single connection between them. The add_flow
method is used to add the flow data for the connection, specifying the source, target, and flow (which can be either a number or a percentage).
Creating Sankey Charts with Plotly
Plotly is a powerful online data visualization tool that can be used to create interactive Sankey charts. To create a Sankey chart with Plotly, you’ll need to use the plotly.graph_objs.Sankey()
method to create the chart, and then specify the necessary details such as the nodes and flows.
Here’s an example of how to create a simple Sankey chart using Plotly:
“`python
import plotly.graph_objs as go
Create the nodes
nodes = go.Sankey(node={‘label’: [‘Category A’, ‘Category B’],
‘x’: [0, 1],
‘y’: [0, 1],
‘marker’: {‘color’: ‘blue’} })
Create the flows
flows = go.Sankey(link={‘source’: [0, 0, 1],
‘target’: [1, 2, 2],
‘value’: [50, 30, 20],
‘color’: [‘green’, ‘red’, ‘orange’]})
Create the chart
chart = go.Layout(title=’Example Sankey Chart’)
Create the figure
fig = go.Figure(data=[node, flow], layout=chart)
Show the chart
plotly.offline.iplot(fig)
“`
In this example, the nodes are created with labels and positions, while the flows are defined using source and target nodes, as well as values and colors for the connections. The go.Figure
method is then used to create the chart object, which is displayed using the plotly.offline.iplot
method.
Creating Sankey Charts with D3.js
D3.js is a powerful JavaScript library for creating custom Web-based data visualizations. To create a Sankey chart using D3.js, you’ll need to use the Sankey module included in the D3.js library.
Here’s an example of how to create a simple Sankey chart using D3.js:
“`javascript
var sankey = d3.sankey()
.size([width, height])
.nodes([[], []])
.links([]);
sankey.update({ values: [{ source: 0, target: 1, value: 50 },
{ source: 1, target:
SankeyMaster
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