A treemap makes relative file sizes visible as rectangles. A sunburst makes the folder hierarchy visible as rings. Both help you explore a disk, but they emphasize different parts of the same information.
A treemap divides a rectangle into smaller rectangles. A file's area represents its value under the chosen size metric, while files in a folder form a group. Large items stand out even when their names would be hard to spot in a long directory listing.
This view is useful when your question is “Which items dominate this folder?” It can reveal both a single large video and a dense collection of smaller build products. Its limitation is that a deeply nested path can be less obvious without a breadcrumb or inspector.
02 A sunburst makes the path visible
A sunburst arranges a hierarchy around a center. Each ring represents another level, and a child segment sits within its parent's angle. You can follow a broad segment outward to see how a large folder divides into smaller folders and files.
Compare angular width among siblings. The area of a segment at an outer ring is not directly comparable with the area of a segment near the center: the radius changes too. Read the selected item's numeric size when making a precise comparison.
The layout is useful for the question “Which branch should I follow next?” Deep hierarchies and very small items can become difficult to select, so drill-down behavior and the accompanying file list matter as much as the chart. DaisyDisk's disk map guide illustrates how its sunburst navigation works.
03 Choose the view for the task
What you want to do
Treemap
Sunburst
Find a few dominant files
Rectangular areas make large items prominent.
Large sibling segments lead you into the relevant branch.
Understand nested folders
Grouping helps; use the path and inspector for depth.
Rings make parent-child relationships explicit.
Inspect many small files
Zoom into the group to separate small tiles.
Drill into a segment to give its children more room.
Compare exact sizes
Read the numeric values using the same size mode.
Read the numeric values using the same size mode.
Neither view can tell you that a file is disposable. The map answers where the storage is represented; your project knowledge decides what to do with it.
04 Try both on the same folder
Choose a folder you know well, such as Downloads or a completed project.
In the treemap, identify the largest tile or cluster. Read its path and size.
In the sunburst, follow the corresponding branch. Notice whether the parent-child structure helps explain the cluster.
Preview a few candidates and check the file list. Choose the view that makes the next decision easier.
For example, a large Downloads folder may contain one video export and many installers. The treemap helps you see the export's relative weight. The sunburst becomes more useful when those downloads are organized into nested client or project folders. This is a workflow example, not a performance benchmark.
05 The size mode matters more than the shape
Before comparing two maps, check whether both scanned the same location with the same access and size settings. Logical file size, allocated size, and space recovered after deletion are different measurements. APFS shared blocks and snapshots add another reason not to equate a shape with a guaranteed saving.
A different picture may reflect a different size mode or incomplete scan, rather than a better layout. Read Counting bytes on APFS for the accounting details.
06 Use both views in Delve
Delve includes a treemap and a sunburst so you can switch perspective while inspecting your storage. Use the map to locate an area, the path to identify it, and Quick Look to understand a file before adding it to the Collector.