The Heat Map is a two-dimensional representation of data, in which values are encoded in colors and thus provide viewers with convenient, visualized information. Essentially, this type of chart is a data table with rows and lines denoted by different sets of categories. Each table cell can contain a numerical or logical value that determines the cell color based on a given color palette.

Due to all these peculiarities, heat maps are a convenient data visualization tool for comparing categories, using color to emphasize relationships between data values that would be much harder to understand in a simple table with numbers.

To make such a chart easier to grasp, it is possible to make cells display values such as amounts for numerical data or symbols (dots, ticks, etc.) for logical (Boolean) values.