Working with Bubble Plots

About Bubble Plots

A bubble plot displays the values of at least three measures by using differently sized plot markers (bubbles) in a scatter plot. The values of two measures are represented by the position on the plot axes, and the value of the third measure is represented by the marker size.

You can create animated bubble plots to display changing data over time.

Data Roles for a Bubble Plot

The basic data roles for a bubble plot are:

X axis

specifies the measure that is assigned to the X axis.

Y axis

specifies the measure that is assigned to the Y axis.

Bubble size

specifies the measure that determines the marker size.

In addition to the basic data roles, you can assign these roles:

Group

groups the data based on the values of the category data item that you assign. A separate set of points is created for each value.

Note: You cannot assign both the Group role and the Color role at the same time.

Color

specifies a data item that determines the color of the bubbles. If you specify a category, then each value of the category is represented by a different bubble color. If you specify a measure, then the measure value is represented by the bubble color.

Note: You cannot assign both the Group role and the Color role at the same time.

Lattice columns

creates a lattice of charts with a column for each value of the category data item that you assign.

Lattice rows

creates a lattice of charts with a row for each value of the category data item that you assign.

Animation

specifies a datetime data item that is used to animate the bubble plot.

Note: The Animation role is enabled only if you assign a data item to the Group role.

Specify Properties for a Bubble Plot

On the Properties tab, you can specify the following options:

Name

specifies the name of the visualization.

Title

specifies the title that appears above the graph.

Note: The Title option is disabled if you select Generate graph title.

Generate graph title

specifies that the graph title is generated automatically based on the data items in the visualization.

Show grid lines

displays grid lines for each tick on the response axis.

Size scale

specifies the type of scaling that is used to draw the bubbles. Select one of the following values:

Linear

specifies that the bubble sizes are scaled relative to the minimum and maximum values (or frequencies) in your data. A negative value is displayed as a smaller bubble than a positive value.

For the Linear scaling type, the difference in bubble sizes might not be proportional to the difference in values.

Magnitude

specifies that the bubble sizes are scaled relative to zero and the greatest absolute value in your data. A negative value is displayed as a hexagon.

For the Magnitude scaling type, the difference in bubble sizes is proportional to the difference in absolute values.

Frequency

specifies whether the frequency is displayed as a count (Count) or as a percentage (Percent).

Note: The frequency values are based on the data that is shown in the visualization (after filters and other data selections have been applied).

Note: This option has no effect if a measure is assigned to the Bubble size role.

Color gradient

selects the gradient colors for the visualization.

You can click the Edit color gradient button

to select the values that are used to assign the colors. See Specify a Custom Data Range.

Reference Lines

adds reference lines to the visualization. To create a reference line, click Create new reference line

, and then specify the parameters for the line in the New Reference Line window.

The name of each reference line appears below the Reference Lines option. You can edit or delete your reference lines by using the icons next to each name.

Using Animated Bubble Plots

About Animated Bubble Plots

An animated bubble plot displays the changes in your data values over time. Each frame of the animation represents a value of the datetime data item that is assigned to the Animation data role.

For example, if you assign a category with the YEAR format to the Animation data role, then each frame of the animation displays a bubble plot of your data for a specific year.

Create an Animated Bubble Plot

To create an animated bubble plot:

Select an existing bubble plot, or create a new bubble plot.
Assign a data item to the Group data role.
Assign a data item with a datetime format to the Animation data role.

Display an Animated Bubble Plot

For an animated bubble plot, a set of animation controls appears at the bottom of the visualization.

Animation Control Tasks
Task	Action
Start the animation.	Click .
Go to the previous animation frame.	Click .
Go to the next animation frame.	Click .
Jump to a specific animation frame.	Use the slider.
Specify whether to repeat the animation.	Select or deselect Loop.
Select the animation speed.	Use the Speed slider.
Track the movement of a specific bubble.	Click the bubble that you want to track.

Note: If you select a bubble to track, the selected bubble is not highlighted.