God! I didn't expect this from randians.
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A heat map is a false color representation which used colors towards red in the spectrum to indicate higher values and the color towards blue to indicate lower values. So on a glance you can see the where things are high and where things are relatively lower.
Few examples of heat map which is used to depict things other than obviously heat
Pressure on foot https://davidchoy.me/StanfordME218d/
Gene expression https://bitesizebio.com/34121/show-disparity-gene-expression-heat-map/#:~:text=A%20heat%20map%20is%20a,of%20multifarious%20high%2Dthroughput%20tryouts.