ColorBrewer

A large collection of palettes based on research into map design and readability, including colour-blindness and the ability to survive photocopying. Palettes are grouped into three types: divergent, qualitative and sequential.

• Divergent: Changes in lightness and often the saturation of two different colours which meet in the middle at an unsaturated colour are used to plot data that deviates around zero or has a critical middle value, like topography.

• Qualitative: Miscellaneous colours typically used to represent information which does not have ordering or relationships.

• Sequential: Incremental changes in lightness and often the saturation using a single hue are used to represent information that has a sequential order.

The numbers at the beginning of each name indicate the number of colours:

Colours from www.ColorBrewer.org by Cynthia A. Brewer, Geography, Pennsylvania State University.