A heatmap is like a choropleth map in that it displays the density of data points in a given area by using colors and shading. Heatmaps are different in that the data represented is not confined to geographical or societal boundaries. For example, the effects and impacts of weather and other natural phenomena are often represented using heatmaps, as they can be better understood when reference to traditional geographical boundaries is removed. A heatmap is created by interpolating discrete points to create a continuous surface. The resulting surface, also known as the density surface, is visualized by a range of colors that represent the density of points in a particular area. Heatmaps help us see the “shape” of the data and highlight areas of concentration where many points are clustered closely together.
A note of caution: While heatmaps are a visually appealing technique, they are probably one of the most commonly misused map types. For more on how heatmaps are misused, read Kenneth field’s blog post: When is a heatmap not a heatmap?
In the following tutorial, you will use Mapbox Studio to create a heatmap that displays the location of meteorite strikes around the world, based on data collected by NASA:
- How is a heatmap like a choropleth map? How is it different?
- What type of data is most appropriate for a heatmap?
- Reflecting on Kenneth Field’s blog post, describe how heatmaps are commonly misused.