Matrix heat charts analyze relationships between two categorical fields, which can be visualized by count or summarized by a numeric field. Each cell in a matrix heat chart corresponds to the intersection of the categories from the Column and Row fields, and all records sharing those two category values will be aggregated into the same cell. For example, in the following diagram, all records with a value of C in the Row field and with a value of X in the Column field will be aggregated into the same cell.
Variables
Matrix heat charts aggregate pairings between the Column and Row fields into a grid of cells.
Note:
The Column and Row fields must be of type date, integer, or text.
By default, a matrix heat chart displays the count of occurrences between the Column and Row field categories. Optionally, a numeric variable can be summarized by choosing a Number field and an Aggregation method. Applying a numeric variable is helpful when you want to investigate the patterns for a secondary field when two categories intersect. The aggregation method can be one of the following:
- Count—The number of records in each cell
- Sum
- Mean
- Median
- Minimum
- Maximum
Appearance
Titles and description
Charts and axes are given default titles based on the variable names and chart type. These can be edited on the General tab in the Chart Properties pane. You can also provide a chart Description, which is a block of text that appears at the bottom of the chart window.
Color
Grid cells are symbolized using graduated colors that correspond to a count or summarized value in the category pairings between the Column and Row fields. A color classification Method, number of Classes, and Color scheme can be adjusted on the Data tab in the Chart Properties pane.
Examples
Create a matrix heat chart to identify the flights that have the highest average arrival delay time between origin and destination city, by setting the following properties:
- Column—DestCity
- Row—OrigCity
- Aggregation—Mean
- Number—DelayTime
Create a matrix heat chart to identify the cities that have the highest count of flights between origin and destination, by setting the following properties:
- Column—DestCity.
- Row—OrigCity.
- Aggregation—Count.
- Number—Leave this property unset.
