When do you need to pay attention to color‑deficiency issues? If you ever design
a map for anyone other than yourself (supposing that you are not color‑deficient)
or your immediate work group, it would be wise to design it as if someone with a
color‑deficiency were going to view your map. Certainly on maps that will be widely
distributed or shown at a conference, you will want to ensure that the colors
are visible
to all audiences, including the color‑blind, by running it through a color‑deficiency
simulation algorithm, such as Vischeck.4 This is a type of Web site where you can
upload a map and have it transform it into a graphic that shows you what your map
would look like to a color‑deficient person. Another option is to begin with a color
palette that is specifically designated as visible to color‑deficient individuals. The
Color Brewer Web site is a handy reference for such palettes