Heat maps are generally used to illustrate
- measurements, for example heat images or distributions in population density maps or
- evaluations, for example of the results of (effect) correlations, such as in hotspot analyses.
This form of graphical representation takes advantage of the fact that viewers intuitively associate increasing temperatures from cold to hot with certain color sequences, for example blue, green, yellow, orange and red. This can be interpreted in a further association step, depending on the context, for example as "increasing significance".
However, since different associations of colors with temperatures are possible depending on technical references or cultural groups, the colors should be directly assigned to the ratings in a legend. For example: Yellow = low significance, Orange = medium significance, Red = high significance.
