When it comes to charts, what usually comes to mind are bar charts, pie charts, trend charts, and so on. This is a classification of charts based on graphical dimensions, which often leads to the misuse of charts.

The purpose of charts is to help us better understand the data. The primary question to answer when choosing a chart is "What data do I have, and what do I need to do with the chart?" rather than "What does the chart look like?". Therefore, we classify charts from the perspective of data and functionality.