> ## Documentation Index
> Fetch the complete documentation index at: https://cubed3-feat-druid-driver-streaming.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Heatmap

> Visualize a measure across two categorical dimensions as a color-coded grid.

Heatmaps render data as a grid where each cell's color encodes a measure value at the intersection of two dimensions. Use them to spot patterns, dense clusters, and outliers across two categorical axes at once.

## Variant

### Color-scaled grid

One dimension on the X axis, one on the Y axis, and one measure mapped to the **Color** channel. Each cell's color encodes that measure's value for its row/column pair.

## Color palette

A continuous gradient palette is applied by default — low values map to the lighter end, high values to the darker end. Change or reverse the palette in the **Color** section of the Style tab.

For custom palettes, see [Color & stacking](/docs/explore-analyze/charts/configuration/color-and-stacking).

## Data structure

A heatmap requires exactly:

* One dimension on the **X axis**
* One dimension on the **Y axis**
* One measure on the **Color** channel

Cells with no data in the result set are left blank.