TreeMap Charts are supposed to illustrate the hierarchical data. It usually looks like a table with cells of different width and height because of the value they represent, colored according to the Color Scale.
This sample of a TreeMap Chart demonstrates how many Starbucks coffeehouses are in each country. The countries are divided into 5 groups, each is formed according to the number of Starbucks: under 10, from 10 to 100, from 100 to 500, from 500 to 1000 and over 1000. The maximum number of Starbucks is in its country of origin, i.e. in the USA - 13 026. The minimum is observed in Cambodia, there is an only Starbucks coffeehouse in the country. The tooltips of a chart are formatted to suit the chart's view far better.