A bubble graph is a graph in which data is represented by the location and size of round data markers (bubbles).
You use bubble graphs to show correlations among three measures, especially when you have a number of data items and you want to see the general relationships.
You could use a bubble graph to plot salaries, years of experience, and productivity for your work force. You expect higher salaries for more experienced employees, and you expect these employees to be more productive.
If this is true, your bubble graph would show large bubbles in the upper-right quadrant of the graph. If, however, you find that most of the large bubbles appear in the lower-left quadrant, then you might want to look at your salary structure or your definition of productivity.
The following types of bubble graphs are available:
BUBBLE
-- Has one Y-axis.
BUBBLE_2Y
-- Has two Y-axes.
The DepthRadius
and DepthAngle
properties of the
Graph
object together specify whether an area graph appears to
have depth.
The following figure shows the data structure of a bubble graph.
The data structure for bubble graphs is as follows:
A group is a three-column set or, if data columns are shown as series, then three-row set of data. A group is represented by all the bubbles for the same dimension member, such as Eastern Region. Groups are hard to identify in a bubble graph, but it is not as important to identify groups. You generally are looking more for the overall pattern of the data markers. Groups have marker text as their labels; the marker text is not visible by default.
A series is represented by all the markers of the same color and is labeled by legend text, such as VHS Camcorder.
Each data marker in a bubble graph represents three group values:
The first measure value is the X value. It determines the marker's location along the X-axis.
The second measure value is the Y value. It determines the marker's location along the Y-axis.
The third measure value is the Z value. It determines the size of the marker.
Bubble graph data has the following guidelines:
Graphs display numeric data only.
Bubble graphs require at least three columns of data (or three rows, if columns represent series). If you pass fewer than three columns (or rows), then the Graph bean displays a message about insufficient data, instead of displaying a graph.
For more than one group of data, the data must be in multiples of three,
such as three columns (or rows) for Tokyo, three for Paris, and so on. If
the last group does not have three columns (or rows), then the graph does
not display that group. The graph notifies any registered AlertListeners
of this problem by sending an AlertEvent
, with DATA_PARTIAL_GROUP
as its ID.
The following bubble graph is populated with the Sales, Units, and Quota measures, in that order. For simplicity in this example, each series of data has only one marker in it. Normally, bubble graphs have a number of markers.
The following crosstab shows the same data as the graph. Notice that there are three
columns of data for each marker in the graph. This picture assumes that
isDataRowShownAsASeries
returns true
.
Handling Problems
in Graph Data
Specifying Data for a Graph
Example: Setting JDBC Data on
a Bubble Graph
Example: Setting Data from a
File on a Bubble Graph