Working with Heat Maps

About Heat Maps

A heat map displays the distribution of values for two data items by using a table with colored cells. If you do not assign a measure to the Color data role, then a cell’s color represents the frequency of each intersection of values. If you assign a measure to the Color data role, then a cell’s color represents the aggregated measure value for each intersection of values.

Data Roles for a Heat Map

The basic data roles for a heat map are:

X axis

specifies the data item that is assigned to the X axis.

Y axis

specifies the data item that is assigned to the Y axis.

Color

specifies a measure that determines the cell color. If you do not assign the Color role, then the cell color indicates frequency.

Specify Properties for a Heat Map

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.

Bin count

specifies the number of value ranges that are represented as cells. Bin count affects only measures.

Show borders

specifies that the borders between cells are visible.

Rotate axis labels

displays the category labels at an angle.

Note: The Rotate axis labels option affects only the values on the X axis.

Note: The Rotate axis labels option has no effect if the heat map contains no categories.

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.

Fit line

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

Note: Fit lines are not available if a category is assigned to the heat map.

Applying Data Analysis

About Data Analysis

For heat maps, 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

[fit-type]. For information about the fit types that are available, see Fit Lines.

Note: Fit lines are not available if your heat map contains categories or hierarchies.