Heatmap visualization

Select the Heatmap option from the visualization dropdown in the upper left.

Heatmaps divide data points into “bins” – segments of the visualization with upper and lower bounds for both . The Bin Size option determines the bounds for each bin. The total number of points that fall within a bin determine the its value and color. Warmer or brighter colors represent higher bin values or density of points within the bin.

Data

• X Column: Select a column to display on the x-axis.
• Time Format: Select the time format. Options include:
  • DD/MM/YYYY HH:mm:ss.sss
  • MM/DD/YYYY HH:mm:ss.sss
  • MM/DD/YYYY HH:mm:ss.SSS
  • YYYY/MM/DD HH:mm:ss
  • HH:mm
  • HH:mm:ss
  • HH:mm:ss.sss
  • MMMM D, YYYY HH:mm:ss

Options

• Color Scheme: Select a color scheme to use for your heatmap.
• Bin Size: Specify the size of each bin. Default is 10.

X Axis

• X Tick Prefix: Prefix to be added to x-value.
• X Tick Suffix: Suffix to be added to x-value.
• X Axis Domain: The x-axis value range.
  • Auto: Automatically determine the value range based on values in the data set.
  • Custom: Manually specify the minimum y-axis value, maximum y-axis value, or range by including both.
    • Min: Minimum x-axis value.
    • Max: Maximum x-axis value.

Y Axis

• Y Axis Label: Label for the y-axis.
• Y Tick Prefix: Prefix to be added to y-value.
• Y Tick Suffix: Suffix to be added to y-value.
• Y Axis Domain: The y-axis value range.
  • Auto: Automatically determine the value range based on values in the data set.
  • Custom: Manually specify the minimum y-axis value, maximum y-axis value, or range by including both.
    • Min: Minimum y-axis value.

The following example explores possible correlation between CPU and Memory usage. It uses data collected with the Telegraf and CPU input plugins.

Join CPU and memory usage

The following query joins CPU and memory usage on _time. Each row in the output table contains _value_cpu and _value_mem columns.

Use a heatmap to visualize correlation

In the Heatmap visualization controls, _value_cpu is selected as the and is selected as the Y Column. The domain for each axis is also customized to account for the scale difference between column values.

Differences between a heatmap and a scatter plot

Heatmaps and Scatter plots both visualize the distribution of data points on X and Y axes. However, in certain cases, heatmaps provide better visibility into point density.

For example, the dashboard cells below visualize the same query results:

Related articles

• Scatter visualization