Treemap charts are used to compare the relative size of groups of data. They can also use a nested data structure, allowing a user to drill down into a group to see its constituent data points.

The default height of treemap is 400px and can be changed. The default height is in pixel units, but can also use percentage string (percentage would be that of the width. For example, height:"50%" would mean that the height is 50% of the width). This allows for preserving the aspect ratio across responsive sizes.

For more information, see: highcharts/chart.height.