62
MaP Design
RGB (red, green, blue), HSB (hue, saturation, brightness), grayscale, and LAB (CIE);
Adobe Illustrator CS allows HSB, CMYK, RGB, and grayscale. Other software has
similar capabilities. Doing a print preview in grayscale lets the mapmaker see what
the map would look like if printed in black and white.
choosIng coloRs
Color should not be used indiscriminately on maps. It should serve a purpose; if one
invests the extra effort and cost called for by color, the effect should justify that extra
effort and cost. Color should be anticipated in the stages of map design, not added as
an afterthought.
Arthur Robinson (1967, pp. 50–61) gave three reasons for the use of color in
cartography:
1. It acts as a clarifying and simplifying element.
It increases the number of
visual levels and acts as a unifying agent.
2. The use of color seems to have remarkable effects on the subjective reactions
of the map reader.
3. It has a marked effect on the perceptibility on the map.
To these might be added:
4. It attracts attention.
5. It leads the eye.
Uses of color
Color as a Clarifying
and simplifying element
This is probably the reason most cartographers would cite for using color. Color is
one of the visual variables of map symbols (see Chapter 7). Different values of a hue
can be used to symbolize numerical values. Different-shaped symbols can be given
the same hue to indicate objects within the same family. Hue can be used to distin-
guish symbols that have the same shape, such as different colored lines for different
routes or kinds of transportation lines. Colored dots can be used to illustrate two
different products or crops on a dot map.
Closely tied to this reason is the use of color to
enhance perceptibility on a map.
Figure 4.6 illustrates a black-and-white route map. Although one can distinguish the
different line patterns and they are explained in the legend, the map would be much
clearer if even one additional color had been used to differentiate the lines (Plate 4.5)
Color is also one of the simplest ways to create a clear figure–ground relationship and
establish visual hierarchies.
Color in Cartographic Design 63
attention attraction
We really do not know why color attracts the eye and is an
attention getter, but it is
undisputed that this is so. It is also not clear which colors have the greatest attractive
power; there are conflicting test results and opinions. Generally, it appears that the
attention-getting value depends on visibility. Therefore, the color that can be seen at
the greatest distance is the one that attracts the eye quickest. It has also been pointed
out that pure hues have greater visibility than tints or tones. However, visibility also
depends on the background. Yellow when next to a blue-black is highly visible, but
when printed on a white page it has very low visibility.
There is also a difference
between
the color used for areas, for typography, or for lines or points.
Study of actual printed maps reveals that cartographers, whether intellectually
or instinctively, accept red as the color highest in attention value since this is the color
most often used when only one color is chosen in addition to black and white. Many
studies certainly indicate that red rates highly as an attention getter. Some textbooks
have used brown or green in addition to black and white on maps. While brown is
generally rated fairly low in attracting the eye, the mere fact that it is the only color
on the page makes it stand out. When only one color is used on a map, such as a red
arrow or one country or region in red, the purpose is usually to draw attention to a
specific feature and to lead the eye.
