What Are Packed Bubble Charts?

See also "How to Make a Bubble Chart" by clicking here.

For background on 3-dimensional (3D) bubble charts, see "What are 3D Bubble Charts" by clicking here.

For background on 2-dimensional (2D) bubble charts, see "What are Bubble Charts" by clicking here.

Packed Bubble charts or packed circle charts show the relationships between data objects in 1-dimension. There are no X or Y axis with packed bubble graphs,instead the bubbles are packed tightly into the area of the chart. Thy are extremely useful graphs for comparing the relationships between data objects by the bubble size.

Packed Bubble Chart Example 1: This chart shows the relationship between costs of the represented projects as represented by the bubble area.

Differentiating Bubbles in Packed Bubble Charts

Bubbles are usually differentiated by color, pattern, number or name labels, or a combination of these. Colors are usually adequate for small numbers of bubbles, but subtle differences in colors become difficult to distinguish in larger number of projects. Therefore, bubble labels or numbers corresponding to a legend can be a more useful method of quickly distinguishing bubbles.

Packed Bubble Chart Example 2: The same as Example 1, but using bubble labels instead of a legend.

Data Proportional to Radius or Area?

Bubble charts can be misleading if care isn’t taken to understand the relationship between bubble size and the data the size represents. If the data is proportional to the bubble radius, the data will be skewed because bubble area grows exponentially as the square of the radius (Area=π*r^2). For a proportionally accurate representation of the data, bubble data should be represented directly by the area using the circumference of the circle, which grows the bubble area linearly in relationship to the diameter (circumference=π*diameter).

Packed Bubble Chart Example 3: The same as Bubble Chart Examples 1 and 2, but the bubble size has been changed to be proportional to the radius. Notice how the bubble sizes compare to Example 1.

Using Blinking Bubbles to Differentiate Bubbles

You can also select individual or groups of bubbles to "blink" on and off. This is a great way to visualize and track specific bubbles in different bubble charts. You can toggle blinking "on" and "off" by clicking a button at the bottom of the form, and you can set the blinking speed in the preferences form.

Packed Bubble Chart Example 4 with Blinking Bubbles.

Crowded or Congested Packed Bubble Charts

Finally, congestion and overlapping bubbles can be a problem with charts that have large numbers of bubbles or tight clusters of small bubbles. This is a significant barrier to using bubble charts for analyzing such data, however, using features like the “Zoom-Boxes” in Bubble Chart Pro™ to instantly expand congested areas makes analyses of these types of charts much easier.

"I highly recommend Bubble Chart Pro for anyone tasked in Project Governance processing. I especially love the zoom function as it allows you to drill into crowed quadrants to see a cleaner picture. Once you start to use it, you’ll never want to display relationships any other way."
Phil F., Administrative Director - Program Management Office, Health Care Industry

Packed Bubble Chart Example 5: This shows how a Bubble Chart Pro™ “Zoom-Box” can be used to expand congested chart areas.

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