How is Italy the country with the highest number of students?
I get the answer from the table, but the chart doesn't tell any story. France, UK and Italy have the same heights.
You can say London is the most popular city in UK. Same way Paris is for France based on the chart, but the about question remains unanswered from the chart.
The Treemap chart visualizes the number in each group and sub-group using the same unit of area. The group with larger area occupied gives the higher population.
You can see that Italy (with Blue color) has the largest area (fixed height, higher width) among the other countries. The same applies for any rectangle within the Treemap.
Please let me know if you still have any other doubts.