A heatmap shows a single measure across two categorical dimensions at once, as a grid of colored cells - one dimension along the bottom, one along the side, and color intensity standing in for the value at each combination. It is the chart type for spotting which combinations of two categories are unusually high or low, without reading a full table of numbers.

Which field becomes the X-axis and which becomes the Y-axis?

The first dimension field you assign becomes the X-axis (bottom), and the second becomes the Y-axis (side). The order you drop the two fields into Column determines which one runs along the bottom versus the side - there is no separate control to swap them after the fact, so assign them in the order you want them to appear.

What do the colors mean, and can I change them?

Color represents the measure's value at each cell, scaled between a low-value color and a high-value color set in Visual Map - by default a theme sequential gradient, but Low Value Color and High Value Color let you set your own two-color gradient instead. The scale's min and max are calculated automatically from the data; there is no manual override.

Can viewers interact with the color scale?

Yes, when Interactive Range is enabled in Visual Map (on by default). Viewers can drag the ends of the color legend to narrow the highlighted value range, which fades out cells outside that range without changing the underlying data. This is useful for isolating just the hottest or coldest cells in a dense grid.

How many fields does a heatmap need?

Exactly two dimension fields and exactly one measure - no more, no fewer. Unlike a Highlighted Table, which accepts up to 10 dimensions and 10 measures, a heatmap's grid layout only works with exactly two categorical axes and one value driving color.

When should I use a heatmap instead of a Highlighted Table?

Use a heatmap when you specifically want to compare a value across two categories laid out as a grid - day of week against hour of day, region against product line. Use a Highlighted Table when you have one dimension and want exact numbers with a magnitude cue, or when you need more than two dimension columns.

Do long category labels get cut off?

The Y-axis labels truncate automatically with an ellipsis if they would otherwise crowd the chart, based on the available space and font size - this happens automatically and adjusts as you resize the chart or change font size, with no manual truncation length required.

Heatmap | Edilitics Docs

Show how a measure varies across two categories at once, shaded by intensity in a grid. Best for spotting hot and cold spots across a matrix of combinations.

A heatmap shows a single measure across two categorical dimensions at once, as a grid of color-shaded cells. Drop exactly two categorical or date fields into Column - the first becomes the X-axis, the second the Y-axis - and exactly one numeric field into Row to drive the color. Use it when the question is "which combination of these two categories stands out," not when you need to read exact numbers.

When to Use

A heatmap trades exact-number precision for at-a-glance pattern recognition across two dimensions simultaneously - day of week against hour of day, region against product category, agent against ticket type. Every cell's color tells you roughly how high or low that combination is relative to the rest of the grid, so a hot spot or dead zone jumps out without scanning a table row by row.

Field order decides axis placement. The first dimension field you assign becomes the X-axis along the bottom, the second becomes the Y-axis along the side. There's no swap control after the fact - if the grid looks rotated from what you intended, reassign the fields in the order you want them to appear.

Switch to a different chart when:

You need exact numbers alongside the magnitude cue, not just color - use Highlighted Table
You have one dimension, not two, to shade by value - use a Highlighted Table with a single column
You want to see the shape of a single measure's distribution, not a two-dimension comparison - use a Histogram

Scenario	X-Axis Dimension	Y-Axis Dimension	Measure
Support ticket volume by day and hour	Hour of day	Day of week	Count of tickets
Website engagement by page and device	Page	Device type	Average session duration
Sales performance by region and product line	Product line	Region	Revenue
Server load by service and time window	Time window	Service name	Average CPU utilization
Survey sentiment by question and respondent group	Question	Respondent group	Average score

Required Inputs

Field	Type	Count
Dimension	Categorical or Date	Exactly 2
Measure	Numeric	Exactly 1

For step-by-step build instructions, see Build Your First Chart.

Formatting Options

The Format tab unlocks after both dimension fields and the measure are assigned.

Style

Use the chart title to state what the grid compares, since two-axis category labels alone don't always make the relationship obvious.

Control	What it does
Show Chart Title	Shows or hides the title.
Enter Chart Title	Title text. Maximum 50 characters.
Font family	Font applied to the title.
Font size	5 to 30.
Bold / Italic	Weight and style.
Alignment	Left, center, or right within the chart container.

Heatmap Styles controls the grid cells' border and the in-cell value labels, in one place.

Control	What it does
Border Color	Color of the thin line separating each cell from its neighbors.
Show Labels	Prints each cell's exact value on top of its color. Off by default on dense grids, since labels can crowd small cells.
Font Family / Color / Font size / Bold / Italic	Styling for the in-cell labels, when shown. Font size up to 18.
Number Type	Default, Scientific, Decimal, or Percentage, for the in-cell labels.
Display Unit	None, Thousand, Million, or Billion, for the in-cell labels.
Decimal Places	0 to 6. Only shown when Number Type isn't Default.

Data Label is a second path to the same in-cell labels controlled in Heatmap Styles above - the Show toggle and styling here write to the same settings. The Vertical Position control in this panel has no visible effect on a heatmap, since cell labels always render centered inside each cell regardless of this setting.

Control	What it does
Show Data Labels	Same toggle as Heatmap Styles' Show Labels.
Font Family / Color / Font size / Bold / Italic	Same styling as Heatmap Styles.
Number Type / Display Unit / Decimal Places	Same number formatting as Heatmap Styles.

Axes

Axis Name labels what each axis represents - the dimension field's name by default, editable per axis.

Control	What it does
Show Axis Name	Shows or hides the axis title. Falls back to the assigned field's name in Title Case when no custom label is set.
Custom label	Overrides the automatic field-name label for that axis.
Font Family / Color / Font size	Styling for the axis name text.

Axis Line controls the visibility and color of the line each axis sits on.

Control	What it does
Show Axis Line	Shows or hides the line itself.
Line Color	Color of the axis line.

Axis Label controls the category names printed along each axis - the X-axis categories along the bottom, the Y-axis categories along the side.

Control	What it does
Show Axis Label	Shows or hides the category labels.
Font Family / Color / Font size	Styling for the labels.
Text Case	Uppercase, lowercase, capitalize, or none.
Max Length	Truncates long Y-axis category names with an ellipsis. The chart also auto-shrinks this based on available space, so labels rarely overflow even without a manual value.

Y-axis label truncation is automatic by default - the chart calculates how much horizontal space labels can use based on chart width and font size, then truncates to fit. Max Length only needs to be set manually if you want a stricter limit than the automatic calculation provides.

Interactivity

Visual Map is the color legend that defines the heatmap's color scale - and the one panel unique to color-scaled chart types like this one.

Control	What it does
Show Visual Map	Shows or hides the color legend entirely. The color scale still applies to the cells either way - this only controls the legend's visibility.
Orientation	Vertical or horizontal placement of the legend.
Vertical / Horizontal Position	Where the legend sits within the chart area.
Interactive Range	When on (default), viewers can drag the legend's handles to narrow the highlighted value range, fading out cells outside it without changing the data.
Low Value Color	The gradient's low end.
High Value Color	The gradient's high end.

The scale's min and max are always calculated automatically from the data currently in the grid - there is no manual override. If you filter the data, the color scale recalculates against the new range, so the same value can shade differently before and after a filter.

The tooltip appears on hover over any cell, showing both category values and the cell's exact measure value.

Control	What it does
Show Tooltip	Shows or hides the tooltip entirely.
Header / value text styling	Font, size, and color for the category and value lines shown in the tooltip.

Animation controls the grid's transition when the chart first renders or the data changes.

Control	What it does
Enable Animation	Turns the transition animation on or off.
Duration	How long the transition takes.
Delay	How long the transition waits before starting.
Easing Function	The transition curve.

Emphasis controls the visual response when hovering over a cell - a scale-up effect and a drop shadow. Off by default.

Control	What it does
Show Emphasis	Turns hover effects on.
Focus Type	Item, Series, or None.
Enable Scale	Scales the hovered cell up slightly.
Scale Size	1.0x to 2.0x.
Shadow Blur / Color / Offset X / Offset Y	Drop shadow styling on the hovered cell.
Border Width	Border added around the hovered cell.

Enable the Toolbox when viewers need to export the heatmap or inspect its underlying data.

Control	What it does
Show Toolbox	Shows or hides the toolbox icon bar.
Save as Image	Adds a download icon that saves the heatmap as a PNG.
Data View	Adds an icon that opens the underlying data table in a separate view.

Best Practices

Assign dimensions in the order you want them to appear. The first Column field becomes the X-axis, the second becomes the Y-axis, with no swap control afterward. If the grid reads backwards from what makes sense for your audience, reassign the fields rather than trying to fix it in formatting.

Reserve in-cell labels for grids small enough to read them. A 5-by-5 grid can comfortably show exact values on top of the color; a 30-by-30 grid cannot. Use Show Labels in Heatmap Styles only when the cell count is small enough that the numbers stay legible.

Pick a gradient with enough contrast to read at a glance. The default sequential theme gradient works for most cases, but if your low and high values need to be unmistakably different, set Low Value Color and High Value Color in Visual Map to two clearly distinct colors rather than two shades of the same hue.

Don't expect the color scale to stay stable across filtered views. Because min and max are recalculated from whatever data is currently in the grid, the same value can shade differently before and after a filter is applied. A heatmap is not a reliable way to compare color across two different filtered views of the same data - use Interactive Range to explore one view at a time instead.

Use a heatmap only when both axes are genuinely categorical or date-based. A heatmap's two dimensions must be exactly two fields - if your real comparison needs more than two grouping dimensions, a heatmap can't represent that, and a Highlighted Table with multiple measure columns is the better fit.

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