Text Material and Typography 51
Parts
of the Letter
Letters are positioned on a
base line (Figure 3.9). The distance from the base line to
the
mean line is called the
x-height, which is literally the height of the letter
x; this
measurement is important in determining type size for maps. Lowercase letters either
rise to the
ascender line, such as
b and
d, or extend down to the
descender line, such
as
p,
q, and
g.
Serifs are short extensions from the ends of the main strokes of a letter;
and
some letters have bowls and
loops (Figure 3.10).
Fonts
A font is all the variations of a typeface of a given size possible. A well-developed
typeface will include roman (upright) forms, italic (slant) forms, and differences in set
or width, giving normal, condensed, and extended forms, and differences in weight,
giving light, medium, and bold faces. Not all standard fonts available on computers
include all of these forms (Figure 3.11).
Typefaces
Thousands of
typefaces or styles are available, although not all are suitable for carto-
graphic work. For ease of study, these faces may be placed into categories according
to the appearance of the letters. A very simple categorization is serif or sans serif, but
because there are some faces that don’t fit into this categorization we can add decora-
tive faces. These faces are only used on maps when a special effect is desired. Often
these are advertising maps. Examples would be
comic book styles, Courier, and
