Multi-Line Graph: Purpose, Code, and Description
Explore how to create multi-line graphs in D3.js by grouping complex data, applying color coding, and adding interactive features. Understand how to pivot data using d3.group, draw multiple lines for different stock symbols, and implement show/hide controls for clarity in your visualizations.
We'll cover the following...
Purpose
Creating a multi-line graph is a pretty handy thing to be able to do, and we worked through an example earlier in the course as an extension of our simple graph. In that example, we used a CSV file that had the data arranged with each line’s values in a separate column.
date,close,open
1-May-12,68.13,34.12
30-Apr-12,63.98,45.56
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This is a common way to have data stored. But if you are retrieving information from a database, you may not have the luxury of having it laid out in columns. It may be presented in a more linear fashion where each line’s values are stored on a unique row with the identifier for the line on the same row. For instance, the data above could just as easily be presented as follows:
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