Treemap
A treemap is a data visualization technique that displays hierarchical data as a set of nested rectangles, where each branch of the tree is represented by a rectangle, which is then tiled with smaller rectangles representing sub-branches. It is commonly used to visualize part-to-whole relationships and compare proportions within a dataset, such as file system sizes, market shares, or budget allocations. The area of each rectangle is proportional to a specified dimension in the data, often with color encoding additional variables like categories or performance metrics.
Developers should learn and use treemaps when they need to visualize large hierarchical datasets in a space-efficient manner, especially for applications like disk usage analyzers, financial dashboards, or interactive data exploration tools. They are particularly useful for identifying patterns, outliers, or dominant categories within complex structures, making them valuable in fields like business intelligence, software development (e.g., codebase analysis), and data science for exploratory data analysis.