Heat maps use cell size and color to display complex information in an intelligible way.
The heat map is one of the most useful and powerful data-analysis tools available in business intelligence. It is a visualization feature that presents multiple rows of data in a way that makes immediate sense by assigning different size and color to cells each representing a row. A color slider at the bottom or on the side of the heat map allows the end-user to easily spot the high and low outliers in the column represented by color.
For example, suppose you manage a sales force of 100 reps. On a data table, you have 100 rows, each representing one of your reps, plus a number of columns displaying (for instance) year to date dollars sold, year to date orders taken, etc.
If you were to represent this data on a conventional bar chart, the resulting visual would be so cluttered it would be practically useless. Instead, on a heat map, you can assign a cell to each rep, year to date dollars sold to cell size and year to date orders taken to cell color. The heat map will immediately sort your data by cell size, thereby allowing you (in our example) to see which rep has sold the most dollars year to date.
Color will immediately show you which reps have taken the most or the least orders; this is further facilitated by the color slider, which will intensify the colors on the high and low end of the spectrum and let the user see outliers.
What to Look for in Web-based Heat Maps
To be even more useful, a Web-based heat map feature within a BI solution should have the following benefits:
Easy integration with other applications such as dashboards
Easy setup even by end-users within an ad-hoc reporting environment
Flexibility to let the end-user choose which data columns to display through cell size and color
Drill-down and drill-through capabilities