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Calendar heat chart

Calendar heat charts visualize patterns in temporal data by aggregating incidents into a calendar grid.

A calendar heat chart can be used to visualize how incident patterns fluctuate within a year, or within a week.

In a year view, each row in the calendar grid corresponds to a month, and each column corresponds to a day of the month.

Calendar heat chart month grid

In a week view, each row in the calendar grid corresponds to a day of the week, and each column corresponds to an hour of the day.

Calendar heat chart week grid

Each cell in a calendar heat chart corresponds to the specific calendar unit defined by the intersection of the row and column, and all incidents sharing those two dimensions will be aggregated into the same cell. For example, when visualizing a dataset spanning multiple years into a year grid, all incidents with the dimensions October and 22 will be aggregated into the same cell, regardless of year. Similarly, when visualizing a dataset spanning multiple weeks into a week grid, all incidents with the dimensions Wednesday and 12pm will be aggregated into the same cell.

Variables

Calendar heat charts aggregate a Date field into a calendar grid. The calendar grid can be divided into one of two Types: Year by month and day of month, or Week by day of week and hour of day.

Note:

The Date field must be of type Date.

By default, a calendar heat chart displays the count of records that took place in each temporal unit. Optionally, a numeric variable can be summarized by choosing a Number field and an Aggregation method. The aggregation method can be one of the following:

  • Count—The number of records in each temporal unit
  • Sum
  • Mean
  • Median

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 taking place in each calendar unit. A color classification Method, number of Classes, and Color scheme can be adjusted on the Data tab in the Chart Properties pane.

Example

Create a calendar heat chart to identify which days of the week and during which times of day most car accidents take place.

  • Date—Date
  • Type—Week by day of week and hour of day
  • Aggregation—Count
  • Number—<empty>

Calendar heat chart showing patterns in car accidents by day of week and hour of day