A Heatmap or heat map is a visualization of color-coded cells in the form of a table. It has categorical data on both the X and Y-axis, respectively. The cells represent the numeric values or color as you desired. We can even use shades of the same color in visualization, the darker the color, the higher would be its value and vice versa. There is also a color legend associated with the chart that gives a brief insight, which color represents a positive outcome and which one shows negative.
Why do you need it?
We need a heatmap to visualize two categories, and the values associated with them using colors. The use of color shades makes it easy to understand the data in a sight without giving any stress to the brain. Furthermore, the use of this data helps to acquire profitable outcomes.
What kind of data you can visualize with it?
A heatmap is best suited for categorical-data. Assume you have to represent the attendance of an employee, then the heatmap is an alternative for you. You can use colors like green for 90%-100% attendance, orange for 70%-90% attendance, yellow for 50%-70%, and red for below 50%. This will help every employee to visualize at what position they stand.