Map Accessibility & Color-deficient Vision

Color Oracle

Our free Color Oracle software simulates color impaired vision, and shows how people with common color vision impairments see maps and other information graphics. This allows designers to ensure that their graphics are barrier-free.



Code on Github for Mac and Java
  • Stacks Image 537
    A color wheel as seen by people with normal color vision.
  • Stacks Image 538
    5% of all men have deuteranopia or a milder form. They confuse red and green colors.
  • Stacks Image 539
    2.5% of all men have protanopia or a milder form. They also confuse red and green colors.
  • Stacks Image 549
    Tritanopia is very rare and only affects 0.3% of women and men.

Accessible Color Design

Eight percent of men are affected by color vision impairment – they have difficulties distinguishing between colors. Barrier-free color design is important for this relatively large group of readers.

The paper below discusses color combinations and alternative visual variables for map symbology that those with color vision impairments can distinguish unambiguously. The presented techniques help the cartographer produce maps that are easy to read for those with color vision impairments and still look good for those with normal color vision.
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Jenny, B. and Kelso, N. V. (2007)
Color design for the color vision impaired.
Cartographic Perspectives, 58, p. 61-67. High resolution for print (20 MB).

Jenny, B. and Kelso, N. V. (2007)
Designing maps for the colour-vision impaired.
Bulletin of the Society of Cartographers SoC, 41, p. 9-12.