Treemap
Treemap
What Is This Report Type?
A Treemap displays hierarchical data as a set of nested rectangles. Each branch of the hierarchy is represented as a rectangle, and its sub-branches are tiled within it. The area of each rectangle is proportional to the value it represents, making it easy to compare the relative size of items within the same parent category and across the entire dataset at once.
Why Is It Used?
Treemaps are used when you need to visualize part-to-whole relationships across a hierarchy and the total number of categories is too large for a pie or donut chart. They maximize screen real estate by filling the entire canvas with data—every pixel communicates information about relative size and category structure.
Key Features and Characteristics
| Feature | Description |
|---|---|
| Area-Encoded Values | Rectangle size is proportional to the value—larger rectangles = larger values. |
| Hierarchical Nesting | Parent categories contain nested child rectangles, revealing structure and composition simultaneously. |
| Color Coding | Color encodes a secondary dimension (e.g., growth rate, category) overlaid on the size dimension. |
| Labels | Category name and value are displayed directly on each rectangle when space permits. |
| Space Efficiency | Uses the full canvas, making it one of the most data-dense chart types available. |
When to Use It (Use Cases)
- Budget Breakdown: Visualizing company spending by department → cost category → individual line item.
- Product Revenue: Showing revenue contribution by product category → sub-category → SKU.
- File System Analysis: Mapping disk usage by folder → subfolder → file size.
- Portfolio Exposure: Displaying investment portfolio by asset class → sector → individual holding.
Real-Time Business Example
Scenario: A CFO wants a single-screen view of the company’s $10M operating budget broken down by department and cost category.
Visualization: A Treemap shows four large parent rectangles: Engineering (40%, largest), Sales (30%), Marketing (20%), and G&A (10%). Inside the Engineering rectangle, nested sub-rectangles show Salaries (60%), Cloud Infrastructure (25%), and Tools & Licenses (15%). The CFO immediately sees that Engineering-Salaries is the single largest cost item by area—no table scanning required.
Common Metrics Displayed
- Revenue Contribution: Revenue by product line → sub-category → individual product.
- Cost Structure: Operating expenses by department → cost center → line item.
- Market Share: Market capitalization by sector → industry → company.
- Inventory Value: Stock value by warehouse → category → SKU.
User Interactions
| Interaction | Behavior |
|---|---|
| Filters | Filter by parent category or date range to focus on a specific branch of the hierarchy. |
| Hover / Tooltip | Hovering reveals the category name, hierarchy path, value, and percentage of parent/total. |
| Click / Drill-Down | Clicking a rectangle zooms into that category, expanding its children to fill the full canvas. |
| Breadcrumb Navigation | A breadcrumb trail above the chart allows navigation back up through the hierarchy levels. |
| Export | Export to Excel. |
Creation Steps
- Select Treemap as the report type.
- Group By: Drag a hierarchy field (e.g., Department) or multiple fields for nested levels (e.g., Department → Cost Category).
- Metrics: Drag the value field for rectangle sizing (e.g., Budget Amount).
- Color (Optional): Drag a secondary field for color encoding (e.g., Growth Rate).