Results from research on the consistent use of basic color names, on c
olors that look the same with impaired color vision, and on changes in
color appearance caused by surrounding colors have application in car
tography. These results are synthesized to recommend the following pai
rs of hues of use on thematic maps suited to diverging color schemes:
red/blue, orange/purple, and yellow/purple. These recommendations are
robust because they may be communicated verbally and require no partic
ular color charts or color measurements for use. These color pairs wil
l aid in producing maps of differences and of changes that can be read
accurately by all map users.