Color Scales

Color Map

Assign colors to data values

Data values might be discrete, e.g., ordinal or categorical data, or continuous, e.g., quantitative data representing continuous data such as temperature or humidity.
A color map is a scheme to assign colors to data values, i.e., map a discrete/continuous domain of data values to a discrete/continuous range of colors.
In D3, color scales are used to map data values defined in a domain to a range of colors.
Quantitative data: continuous interpolation from data to hue (color), value, and saturation (probably also to transparency)
Categorical or ordinal data: discrete mapping from data to a set of discrete and distinct colors.

This applicating visualizes different colors scales implemented in D3.