Power BI - How to Create a Treemap?

A TreeMap in Power BI is a visualization that helps us to display hierarchical data through a set of nested rectangles. Each rectangle represents a category or subcategory and their size reflects the value they represent. Larger values are shown as larger rectangles making it easy to identify trends and patterns in the data. They are useful for displaying parent-child relationships and data distribution across categories.

Use of a Treemap

Here are a few reasons why we should consider using a TreeMap:

1. Visualize Hierarchy: TreeMaps are ideal for displaying hierarchical data which helps in showing how smaller categories fit within larger ones. This helps understand the relationship between different levels of data.
2. Spot Patterns Quickly: The size and color of each rectangle help highlight key trends or outliers in our data which makes it easier to analyze large datasets and spot anomalies.
3. Compact Representation: Instead of using multiple charts or visuals, a TreeMap consolidates everything into a single view. This compact representation makes it easier to compare categories and subcategories in a clear and simple way.

Loading Dataset for a TreeMap in Power BI

When creating a TreeMap in Power BI there are several options. Here we’ll see a real-life example by using a dataset of employees for better understanding. Let’s see through the step-by-step implementation process:

Stepwise Implementation

Step 1: Prepare the Dataset

For this example, we will use the employee dataset which can be downloaded from here and it includes columns like:

• Department
• Employee Name
• Salary
• Bonus.

Step 2: Visualizations section, click on the Treemap chart.

Step 3: An empty treemap will be created. This treemap does not contain any fields. Our next task is to add columns to it.

Step 4: Drag the Department column and drop it into the Category field of the TreeMap. At this point, we will not see any rectangles but this will be resolved in later steps.

Step 5: Under the values section, drag and drop the Salary column. We can see that a treemap is created with three rectangles in it which represents the 3 departments.

Step 6: Details section can be used to form a child of the parent i.e category. Drag and drop Employee Name into the Details section. Now, we can observe that for each department, we have the names of the employees separately showing their Salary. Here Employee's Name is the child and Department is the parent.  

Step 7: Our next task, is to add Tooltips to the map. Tooltips provide additional information whenever we hover at a data point in our TreeMap. In the below image, we can see that we have hovered at the employee ihsura and we view the previously added tooltips i.e Department IT, Employee Name ihsura, Sum of Salary 50K. These tooltips appeared as we have added these measures previously.

Now think what if we want to add a Bonus to this list. Drag and drop Bonus under Tooltips. Now again hover at employee ihsura. We can see that a Bonus of 50K is added. 

By following these steps, we can effectively create and customize a TreeMap in Power BI which helps in making it easier to visualize and interact with hierarchical data for deeper insights.