"Some of the most important aspects of cartography are those which are most subtle like colors and fonts."
-Matthew Gilmore, IT Specialist
District of Columbia Department of Consumer and Regulatory Affairs
In typography, a font (also fount) is traditionally defined as a complete character set of a single size and style of a particular typeface. A simple definition for font is “all the variations of a typeface of a given size possible” —including variations in weight, italics, and kerning.  For example, italicized Times New Roman at 24 point is a different font than italicized Times New Roman at 28 point. Another way to think of it is that the typeface is a family and one font is an individual family member.
In traditional manual printing (letterpress), the font is a complete set of metal type that is used to typeset an entire page. Unlike a digital typeface, it does not include a single definition of each character. Commonly used characters (such as vowels and periods) have more physical type-pieces included. A font would often be sold as 12pt 14A 34a, meaning that it would be a size 12 point font containing 14 uppercase 'A's, and 34 lowercase 'A's. The rest of the characters would be provided in quantities appropriate for the distribution of letters in that language. Some metal type required in typesetting, such as dashes and line-width spacers, were not part of a specific font in pre-digital usage but were separate, generic pieces. Line spacing was called "leading", because the lead strips used were made of lead.
In the late 1800s, "hot lead" typesetting was invented, in which type was cast as it was set, either piece by piece (as in the Monotype technology or entire lines of type at a time (as in the Linotype technology).
Besides the character height, there are several characteristics which may help identify distinct fonts based on the script(s) that the typeface supports. In European alphabetic scripts, i.e. Latin, Cyrillic and Greek, the main properties are stroke width(weight), and the style or angle.
The regular, or standard font, is often labeled roman, both to distinguish it from bold or thin and from italic or oblique. The keyword for the default, regular case is often omitted for variants and never repeated. Otherwise, it would be Bulmer regular italic, Bulmer bold regular, and even Bulmer regular regular.
Different fonts of the same face may be used in the same work for various degrees and types of emphasis.
The weight of a particular font is the thickness of the character outlines relative to their height. Applying bold to a font makes the font wider relative to the height. A typeface may come in fonts of many weights, from ultra-light to extra-bold or black. It is common for a typeface to have four to six weights, and a few typefaces have as many as a dozen. Many typefaces for office, web, and non-professional use come with a normal and bold weight. If no bold weight is provided, many renderers (browsers, word processors, graphic and DTP programs) can "fake" a bold font by rendering the outline a second time at an offset or smearing it slightly at a diagonal angle.
The base weight differs among typefaces; that means one normal font may appear bolder than some other normal font. For example, fonts intended to be used on posters are often quite bold by default, while fonts for long runs of text are rather light. Therefore weight designations in font names may differ in regard to the actual absolute stroke weight or density of glyphs in the font.
Attempts to systematize a range of weights led to a numerical classification first used by Adrian Frutiger with the Univers typeface, although therein only ranging from 3 to 8. The TrueType font format introduced a scale from 100 through 900, also used in CSS and OpenType. The first algorithmic description of fonts was perhaps made by Donald Knuth in his Metafont and TeX system of programs.
The method of describing font weight differs between type foundries and designers. However, the relative order is generally uniform and is something like the following:
- normal / regular / roman / plain
- demi / semi-bold
- extra-bold / extra
- ultra / ultra-black
The terms normal, regular and plain, sometimes also book, are being used for the standard weight font of a typeface. Whether "book" is lighter or heavier than regular is not entirely consistent across typefaces, though "lighter" seems to be more common.
In today's European typefaces, especially Roman ones, the font style is usually connected to the angle. When the normal, Roman or upright font is slanted – usually to the right in left-to-right scripts – the lowercase character shapes change slightly as well, approaching a more handwritten, cursive style. In this italic type, character edges may even connect, and ligatures are more common. Although rarely encountered, a typographic face may be accompanied by a matching calligraphic face, which might be considered a further font style of one typeface.
In many sans-serif and some serif typefaces, the characters of the italic fonts are only slanted (oblique), which is often done algorithmically, without otherwise changing their appearance. On the other hand, there are typefaces with upright characters that take a more cursive form without a change in angle. For example the Cyrillic minuscule ‘?’ may look like a smaller form of its majuscule '?', or more like a roman small "m" as in its standard italic appearance; in this case, the distinction between styles is also a matter of local preference.
In Frutiger’s nomenclature the second digit for upright fonts is a 5, for italic fonts a 6.
The two Japanese syllabaries, katakana and hiragana, can be seen as two styles or typographic variants of each other, but are usually considered distinct character sets.
Cursive-only scripts such as Arabic also have different styles. Examples of this are Naskh and Kufic, although these often depend on application, area or era.
There are other aspects that can differ among font styles, but more often these are considered immanent features of the typeface. These include the look of the minuscules, which may be smaller versions of the capital letters (small caps) although the script has developed characteristic shapes for them. Some typefaces do not include separate glyphs for the cases at all, thereby abolishing the bicamerality. While most use uppercase characters only, some labeled unicase exist which choose either the majuscule or the minuscule glyph at a common height for both characters.
Italic and Oblique
As demonstrated in the Typography section, an italicized font differs from an oblique font. While both are slanted, an italicized font is drawn with a more calligraphic style. Oblique fonts are normalized font types that are slanted usually 8 - 12 degrees. 
Some typefaces include fonts that vary the width of the characters (stretch). Narrower fonts are usually labeled compressed, condensed or narrow. In Frutiger’s system, the second digit of condensed fonts is a 7. Wider fonts may be called wide, extended or expanded. Both can be further classified by prepending extra, ultra or the like. These separate fonts have to be distinguished from techniques that alter the letter-spacing to achieve narrower or smaller words, especially for justified text alignment.
Some professional digital typefaces include fonts that are optimised for certain sizes. There are several naming schemes for such variant designs. One such scheme, invented and popularized by Adobe Systems, refers to the variant fonts by the applications those are typically used for, with the exact point sizes intended varying slightly by typeface:
- Poster (extremely large sizes, usually larger than 72 point)
- Display (large sizes, typically 19-72 point)
- Subhead (large text, typically about 14-18 point)
- (regular is usually left unnamed, typically about 10-13 point)
- Small text (SmText, typically about 8-10 point)
- Caption (very small, typically about 6-8 point)
Type Size Measurements
Fonts are measured by a unit of measure called a point. A point is 1/72 or .0138 of an inch (~0.0353 cm). For example, when one is using 12 point font, the size is 12/72 or 1/6 of an inch. In most software programs, type size is labeled as pt, which is simply an abbreviation of point. In typography, a point is the smallest unit of measurement. The current standardized unit for measuring type size is the desktop publishing point (DTP). One important thing to note is that the point size displays itself differently for each typeface and font. For example, in the processing program Microsoft Word using 12 point font size in Times New Roman will look larger than using 12 point font size in Angsana New.
A pica, like the point, is another size or unit of measure for fonts or type. A pica is 12 points, or 1/72 of a foot.
Font metrics refers to metadata consisting of numeric values relating to size and space in the font overall, or in its individual glyphs. Font-wide metrics include cap height, x-height, ascender height, descender depth, and the font bounding box. Glyph-level metrics include the glyph bounding box, the advance width (total space for the glyph), and sidebearings (space that pads the glyph outline on either side).
Serifs are the details on the end of strokes in letters and symbols. They are, in essence, the decoration. Serif fonts can be divided into four categories: old style, transitional, modern, and slab serif.
- Old style or humanistic serif fonts originated during the 15th century and are based on humanistic calligraphy. These font types have very little distinction between the thick and thin lines that comprise a letter. They also display diagonal stress, which means the thinnest parts of the letter are those that are at an angle. These fonts are almost always bracketed and often considered the easiest to read. Garamond is an example of old style.
- Transitional serif fonts are in between old style and modern fonts, hence the name. The distinction between thick and thin lines is more pronounced than the old style, but not quite as bold as the modern style. These are among some of the most commonly used fonts, such as Times New Roman.
- Modern serif fonts have very distinct differentiation between thick and thin lines. They are generally more difficult to read than the other fonts. Bodoni MT is an example of modern.
- Slab serif or Egyptian fonts have virtually no distinction between thick and thin lines. Rockwell and Courier New are examples of slab serif.
Sans comes from the Latin term sine (without), and serif (short lines), which originates most likely from the Dutch word schreef (stroke), or from Middle Dutch schriven (write), or from Latin scribere (write).  Hence sans-serif is without the decorative flourishes. Readers tend to prefer sans serif fonts over serif fonts when reading content on a screen.  Readers also tend to comprehend content faster and easier with sans serif fonts. ( Determining to Use Serif or Sans Serif in Labeling)
Proportion between characters is split into two types, proportional and monospace. Proportional uses various lengths of proportion depending on the character used and is often found to be more visually appealing. Monospace uses the same space for each character regardless of character size. The main difference is found in the widths of the fonts. Letters such as 'o' and 'l' will have different widths in proportional fonts, but will have the same width proportion in monospace. Examples of monospace fonts are Courier New, Fixedsys, Monaco, and Andale Mono. Times New Roman, Arial, and Comic Sans are examples of proportional fonts.
The modern use of font in computer use is characterized by the use of an electronic data file containing glyphs and symbols. These fonts are separated out into three separate data formats. Bitmap fonts- These are composed of a matrix of pixels that are brought together to represent the glyph. Outline Fonts- These are composed of vector lines or curves that make each glyph scalable to any size. Stroke Fonts- These are composed of a grouping of lines that have added embedded information that describe each glyph while making them unique.
The term font, a cognate of the word fondue, derives from Middle French fonte, meaning "(something that has been) melt(ed)", referring to type produced by casting molten metal at a type foundry. English-speaking printers have used the term fount for centuries to refer to the multi-part metal type used to assemble and print in a particular size and typeface.
Usage in Cartography
Font choice is important in cartography, as there is often text in many places, such as the title, legend, and labels. As a general rule of thumb, a map should have no more than two different fonts, and of those two, one should be serif and the other sans-serif. Labels typically are in a serif font, and hydrographic features are usually italicized. Since labels can often be very small, it is important to choose a font that can be easily read at small size.
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