---
layout: example
title: Heatmap Example
permalink: /examples/heatmap/index.html
spec: heatmap
image: /examples/img/heatmap.png
---

A [heatmap](https://en.wikipedia.org/wiki/Heat_map) of annual temperatures in Seattle, organized by day versus hour. How do different choices of color palette affect the clarity of the patterns? For an alternative design using area charts, see the [Annual Temperature example](../annual-temperature). This example uses a grid of [`rect`](../../docs/marks/rect) marks. For an example that instead generates heatmaps as rendered [`image`](../../docs/marks/image) marks, see the [Density Heatmaps example](../density-heatmaps).

{% include example spec=page.spec %}
