Color blindness affects 4.5% of the population, approximately 1 in 12 men (8%) and 1 in 200 women (0.5%). Worldwide, there are approximately 300 million people with color blindness, almost the same number of people as the entire population of the USA.
Most people with the conditions that cause color blindness are able to see images clearly but are unable to fully ‘see’ red, green or blue light. There are different types of color blindness which result in different levels of color perception, as well as extremely rare cases where people are unable to see any color at all.
The different anomalous conditions are:
Deuteranomaly which is a reduced sensitivity to green light and is the most common form of color blindness.
Protanomaly, which is a reduced sensitivity to red light.
Tritanomaly which is a reduced sensitivity to blue light.
The color palette being used on our existing thematic maps was designed to be accessible for the majority, including those with some degree of vision deficiency. However, we realized it was not adjustable for everyone. Those with specific color vision deficiencies (also known as color blindness) were not able to visualize and analyze data properly on GIS data web tools.
Looking at the Color Blind Vision image, one can experience how colors 2-3, 4-5-6, and 6-7 are difficult for some website visitors to distinguish clearly. They can be interpreted as the same hue in the eyes of a person with color blindness.