What is a 'heat map' in data visualization?

A heat map is defined as a diagram displaying data values using a color gradient, which allows for the visual representation of data through variations in color. This format effectively communicates the intensity or frequency of data at different locations, making it easier for viewers to discern patterns, correlations, or areas of concentration across a dataset.

For example, in a heat map representing website activity, warmer colors might indicate higher traffic levels, while cooler colors show lower engagement. This quick visual reference can highlight significant trends or outliers in a dataset, facilitating data analysis, understanding, and better decision-making.

Other chart types, such as bar charts or line graphs, provide different forms of data representation, which may not convey the same level of intensity or density as a heat map does. While a table of numerical data presents factual values clearly, it lacks the ability to quickly highlight trends or patterns visually.