Create a Heatmap in Excel by Jonathan Schwabish.
From the post:
Last week, I showed you how to use Excel’s Conditional Formatting menu to add cell formats to highlight specific data values. Here, I’ll show you how to easily use the Color Scales options in that menu to create a Heatmap.
Simply put, a heatmap is a table where the data are visualized using color. They pop up fairly regularly these days, sometimes showing the actual data values and sometimes not, like these two I pulled from FlowingData.
In addition to this post, there are a number of other Excel-centric visualization posts, podcasts and other high quality materials.
Even if you aren’t sold on Excel, you will learn a lot about visualization here.