64
MaP Design
Color Preferences
As mentioned above, color is one of the most frequently criticized aspects of a map.
People have definite color preferences. However, although
studies have been done
testing color preferences, they often look at color in the abstract, not color used for
specific purposes. Thus, a person might like red cars, but not want to sleep in a red
bedroom. Preferences appear to change with age, different cultures seem to have dif-
ferent preferences, and men and women have different preferences. Although the lit-
erature on color preference dates back to work by Goethe, and supposed preferences
have been exploited on propaganda maps (Tyner, 1974), color preference is normally
not a good basis for choosing colors on maps.
Color associations and Connotations
Color associations and color connotations can be considered, but must be used with
care. Colors have been associated
with a variety of attributes, such as smell and
temperature, but many of these associations are either individual or cultural. Tem-
perature is one of the few associations that approaches universal:
colors are com-
monly described as “warm” or “cool.” Reds, oranges, and yellows are warm colors
and blues, purples, and greens are cool colors. This association is strong enough that
maps showing temperature typically use warm colors for hot temperatures and cool
colors for cold ones. Blue for water is another common association that is used almost
universally on maps, even for polluted water features.
Sometimes these conventions create confusion. Climate maps commonly repre-
sent desert areas in shades of tan or orange and rainy areas in blue. Hypsometric (ele-
vation) maps, which show only elevation, frequently represent lowlands with greens
and highlands with reddish browns. This is based on the idea that cool colors appear
to recede and look farther away and warm colors look closer to the viewer. Unskilled
readers often interpret these hypsometric colors not as indications of elevation, but
as representations of vegetation, climate, or rainfall. The green areas (lowlands) are
perceived erroneously as moist and lush and the brown areas as hot and dry. Clear
legends are important.
Colors also have connotations, such as red for danger and yellow for caution; we
speak of “feeling blue” or “seeing red.” These connotations can be taken into con-
sideration and have been used on maps, but again, one must remember that these are
not universally accepted meanings and vary by culture.
It might seem that associating red with courage and yellow with cowardice would
have no relationship to the use of color on maps, but coloring a country yellow on a
map might prompt an unfavorable reaction because the people of that country are
offended by the supposed symbolism. It is always a serious mistake to use stereotypi-
cal skin colors for maps showing racial patterns because the likelihood of causing
offense is great. It is easy to use more abstract colors.
In the United States, income and other financial
subjects are often shown in
shades of green. This makes some sense because U.S. paper money is primarily green,
but it doesn’t work in other countries where the currency might be pink or purple.
It is impossible to take into account all the possible reactions to specific colors,
but it is helpful to be aware of some of the more common color associations. Henry
Color in Cartographic Design 65
Dreyfuss’s
A Symbol Sourcebook is a valuable reference for the symbolic meaning of
color.
As with other design decisions, when choosing colors for a map, ask who is my
audience, what is the nature of the data, where and how will the map be viewed, and
what is the purpose of the map?
audience
When considering the audience, the user’s
visual abilities, color preferences,
color
associations, and color connotations come into play. Color blindness affects a por-
tion of the population. There are varying kinds of color blindness, such as red–green,
blue–yellow, and monocromatism. The percentage of color blindness within a society
varies from culture to culture, but generally more men are afflicted than women.
While normally one isn’t designing a map strictly for that segment of the population,
it is wise to choose colors that do not create problems.
Viewing
the Map
Where and how the map will be viewed is a major consideration. As we have seen,
primary colors differ for light and pigment and a color scheme that looks good on
a high-quality monitor will look quite different when printed. Colors on a monitor,
because they are based on additive primaries, look
different from printed colors,
which are based on subtractive primaries. Therefore, even if designing a print map on
screen using a CMYK pallette, the color scheme needs to be tested on paper. Maps
that will be viewed through a data projector, as for PowerPoint projections, need to
be designed for that purpose (if possible). Unfortunately, the cartographer has no con-
trol over the type of projector used and how it has been calibrated, but some schemes
work better than others. ColorBrewer (see below) suggests color schemes that are
appropriate for projectors.
