Working with Scatter Plots

About Scatter Plots

A scatter plot displays the values of measures by using markers. When you apply more than two measures, the visualization displays a scatter plot matrix. A scatter plot matrix is a series of scatter plots that display every possible pairing of the measures that are applied to the visualization.

If you create a scatter plot that has a very large number of data values, then the scatter plot is rendered either as a heat map (for two measures) or as a correlation matrix for three or more measures.

Data Roles for a Scatter Plot

The basic data role for a scatter plot is a measure. You can assign any number of measures. If you assign a single measure to a scatter plot, then the values are plotted along a line.

In addition to measures, you can assign a Group variable. The Group variable groups the data based on the values of the category data item that you assign. A separate set of scatter points is created for each value of the group variable.

You can add data items to the Data tips role. The values for the data items in the Data tips role are displayed in the data tips for the scatter plot.

Specify Properties for a Scatter 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 plot axes.

Marker size

specifies the size of each marker in pixels.

Fit Line

adds a fit line to the scatter plot. For information about the fit types that are available, see Fit Lines.

Note: Fit lines are not available if a grouping variable is assigned to the scatter plot.

Reference Lines

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

, 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.

Applying Data Analysis

About Data Analysis

For scatter plots, you can apply the following data analyses:

Correlation

identifies the degree of statistical correlation between the variables in the visualization. For more information, see Correlation.

Fit Line

plots a model of the relationship between the variables in the visualization.

There are many types of fit lines, including linear fit, quadratic fit, cubic fit, and penalized B-spline. For more information, see Fit Lines.

Correlation is applied to your visualization automatically when you add a linear fit line. It is not available with other fit types.

Enable Data Analysis

To add a fit line to your visualization, select the Options

drop-down list from the visualization toolbar, and then select Fit Line and select the fit type. For details about the fit types that are available, see Fit Lines.