Histograms visually summarize the distribution of a continuous numeric variable by measuring the frequency at which certain values appear in the dataset. The x-axis in a histogram is a number line that has been split into number ranges, or bins. For each bin, a bar is drawn in which the width of the bar represents the range of the bin, and the height of the bar represents the number of data points that fall into that range.
The histogram below visualizes distribution of dissolved oxygen in water bodies.
Data
The Data tab configurations include the value that is used to create a histogram, the number of bins, and the overlays that are displayed on the chart. Histograms require one continuous number value on the x-axis.
Bins
The default number of bins is 5. You can adjust this by changing the Bins value on the Data tab. You can change the color, text, and labels of a histogram's bins on the Bins tab .
Overlays
The following descriptive statistics are calculated and displayed on histograms:
- Normal distribution—A bell-shaped curve used to compare data to a normal distribution
- Mean—A single vertical line indicating the mean value of the dataset
- Median—A single vertical line indicating the median value of the dataset
- Standard deviation—Two vertical lines indicating the values of one standard deviation above and below the mean
You can change the color, opacity, and thickness of the line or curve on the Overlay tab.
Axes
The X Axis and Y Axis tab configurations are used to change the specifications for the x-axis and y-axis. You can format the way the x- and y-axis displays titles, as well as labels and other settings that appear in the histogram.
Actions
In an interactive dashboard, a histogram can be configured as either the source or target of an action.
When used as the source of an action, a histogram can support single or multiple selection. This determines how many bins can be selected at one time. Because a bin represents a range of values rather than a single value, selections are based on value ranges. Intermediate bins include their lower boundary and exclude their upper boundary, while the final bin includes its upper boundary to ensure the maximum value is represented.
When a histogram is the target of an action, the action filters the data displayed in the histogram. In some cases, the filtered results may not contain enough variation to generate a meaningful distribution. For example, this can occur when the action resolves to a single feature, when all filtered records contain the same value, or when minimum and maximum values cannot be determined. This is especially common when field mapping is used to filter the same numeric field displayed by the histogram or when a range filter narrows the results to a single value.
Embedded content, details, and feature-based rich text elements are not recommended as action sources for a histogram. These elements typically represent or select a single feature, whereas a histogram is designed to visualize the distribution of values across multiple records. As a result, actions originating from a single-feature context may not produce a meaningful histogram display.