Insights for ArcGIS - Create and use a treemap

Treemaps can be used to view your data in a hierarchical format using nested rectangles. A treemap is like a tree diagram that uses differently sized rectangles to convey numeric values for each branch. The larger the rectangle, the higher the numeric value.

Treemaps can answer questions about your data, such as: What are the proportions of categories to the total?

Examples

An insurance company is reviewing the types of policies it offers to compare its current offerings to the findings from a recently completed market research project. One step in the review is to compare the total value of policies in each policy class. A treemap can be used to visualize the proportion of total insured value (TIV) in each policy class.

Treemap of policy classes and total insured value

This treemap has four rectangles (one for each policy class), with each rectangle representing a portion of the total insured value.

The insurance company decides to limit its focus to states that share coastline along the Gulf of Mexico. Using the location field, the analyst can create a spatial treemap that shows the total insured value for each state (Texas, Mississippi, Louisiana, Alabama, and Florida), with the states organized by their geographic location.

Spatial treemap of total insured values for states on the Gulf of Mexico

This spatial treemap has five rectangles representing the total insured value of each state bordering the Gulf of Mexico.

Create a treemap

To create a treemap, complete the following steps:

Steps:

Select one of the following combinations of data:
- One or two string fields
- One or two string fields plus one or two number or rate/ratio fields
Note:
If you do not select a number or rate/ratio field, your data will be aggregated and a count will be displayed.
Create the treemap using the following steps:
1. Drag the selected fields to a new card.
2. Hover over the Chart drop zone.
3. Drop the selected fields on Treemap.

Additionally, you can create a spatial treemap that displays your data in the same way as a standard treemap, but it's suitable for the arrangement of data with a geographic component because it creates tessellated cartograms for geovisualization (Wood, J., Dykes, J., 2008).

Tip:

You can also create charts using the Chart menu above the data pane or the Visualization type button on an existing card. For the Chart menu, only charts that are compatible with your data selection will be enabled. For the Visualization type menu, only compatible visualizations (including maps, charts, or tables) will be displayed.

Create a spatial treemap

To create a spatial treemap, complete the following steps:

Steps:

Select one of the following data options:
- A location field
- A location field and a string field
- A location field and one or two number or rate/ratio fields
- A location field , a string field , and one or two number or rate/ratio fields
Note:
If you do not select a number or rate/ratio field, your data will be aggregated and a count will be displayed.
Create the spatial treemap using the following steps:
1. Drag the selected fields to a new card.
2. Hover over the Chart drop zone.
3. Drop the selected fields on Treemap.

Usage notes

Treemaps that use no or one number field are symbolized using unique symbols. You can use the Legend button Legend to view the categories and corresponding colors and select features on the chart. To change the color associated with a category, click the symbol, and choose a color from the palette or enter a hex value.

Treemaps that use two number fields can be displayed using graduated colors.

The string field selected on the y-axis groups the data by unique categories that are displayed as proportional rectangles in different colors. Hovering over each rectangle provides a sum or count for each category.

Use the Visualization type button to switch directly between a treemap and other visualizations, such as a unique values map, summary table, bar chart, or line graph.

When you create a treemap, a result dataset Results with the string and number fields used to create the chart will be added to the data pane. The result dataset can be used to find answers with nonspatial analysis using the Action button Action .

How treemaps work

Two types of treemaps can be created in ArcGIS Insights: spatial treemaps and nonspatial treemaps. Categorical values or feature locations define the structure of a treemap, and numeric values define the size or color of the individual rectangles. With either type of treemap, the area represents the numeric value shown on the x-axis. A subcategory can be added, which is nested inside a category, with categories being identified by their different colors. A second numeric field can be used to classify the treemap values using natural breaks.

References

Wood, Jo and Jason Dykes. "Spatially Ordered Treemaps," IEEE Transactions on Visualization and Computer Graphics 14, no. 6 (Nov–Dec 2008): 1348-1355.