Color to represent data values

• Colors can be used to represent data values: incomes, temperature, speed.
• Sequential color scale
  
• This sequence will indicate
  • which values are larger or smaller
  • color scale needs to be perceived to vary uniformly across range
  • how distant two specific values are from each other
    
  • may be based on a single hue (light blue to dark blue) or multiple hues (light yellow to dark red)
  • multi-hue scales follow a color gradient that is considered “natural”

Example: choropleths. Map of annual median income within each county in Texas.