A heat map is a chart that utilizes a matrix of colors to represent data. Each value is assigned a particular color. The chart is used across industries and sectors with the most heavy use concentrated in molecular biology and computer science.
Heat maps are a preferred option because they offer more clarity and speed in interpretation than other tools like numeric values listed on a spreadsheet. They are primarily a replacement for spreadsheets, and are superior to them in most aspects of use. Spreadsheets are vulnerable to errors in analysis an interpretation as they increase in size and complexity. Heat maps not only allow for smooth comparison of large data sets, but they do so within limited space; furthermore, clarity is not sacrificed or negatively impacted (with the aid of software).
Heat maps are commonly used within computer science to represent areas of a web page that have received the most views by visitors. Users find that they offer insight other methods do not. Biology heat maps often represent gene expression across samples.
The most widely used color scheme in heat maps is the rainbow color map. This is because it is easier for humans to perceive various colors than shades of color, however, in smaller heat maps, shades of color are effective because different colors lack the natural perceptual ordering offered by shades of color.
The complex nature of heat maps demands the use of software in their creation and use. Software accelerates what would be a tedious process, and also allows the maps to be interpreted quickly and accurately; for example, software will allow the user to clarify gradient differences and quantify them when necessary, and there is additional functionality like selecting certain regions for comparison or other analysis.