MAPS AND THE NEWS
Journalism provides the public with one of its most valuable
sources of information about other places and to that end,
journalists have used maps to communicate with readers
for many years. Francis Galton prepared the first weather
map, published in The Times of London on April 1, 1875.
It is now a standard in newspapers worldwide. American
journalists used maps as a central reporting technique in covering one of the seminal events of the nineteenth century—the Civil War. Maps displayed the relative location
and movement of troops as well as the terrain and vegetation influencing the outcome of battles. In the twenty-first
century, most Americans have become familiar with the
“red states” and “blue states” that make maps synonymous
with American presidential elections.
Improvements in technology gave the press the ability
to use maps more frequently. In the late nineteenth century,
photoengraving technology made it possible for newspapers
to increase their use of graphics although such publications
as Joseph Pulitzer’s New York World and William Randolph
Hearst’s New York Journal took advantage of these developments to sensationalize the news. Aside from weather
maps, the use of news maps by newspapers was rare before
the twentieth century. The New York Times began to expand
its use of news maps in the 1930s, but not until 1940 did it
average using one non-weather map per issue. (The London
Times reached that average in 1920.) Other papers in the
United States were slower to use maps. Not until 1970 did
the Christian Science Monitor average using a news map
each day, and as late as 1985, the Wall Street Journal used
news maps on average only every other day (Monmonier
1989, 55), The arrival of film technology and then television
increased the use of visuals in news reporting. Maps were
a staple of newsreel coverage of World War II, for example.
With the spread of television during the 1950s, news maps
were seen regularly by millions of viewers. As color television became more common during the 1960s and 1970s,
maps became more sophisticated.
Television surely provided an impetus for newspapers to
use images more often and new technology made it possible for them to do so. During the 1970s, a major advance
occurred in newspaper production with the adoption of
photocomposition, or computer-generated “cold type.”
Improvements in offset printing and the use of electronic
color-separation scanners made it possible for mid-sized
and large dailies to use color during the 1970s and 1980s.
More recently journalists have turned to Geographic Information Systems (GIS) software to take their mapping communication to a higher level. GIS software not only enables
journalists to display data from the U.S. census and similar government sources, but to also map data of their own
creation. Reporters from the Miami Herald were among
the first journalists to use GIS, mapping structural damage
from Hurricane Andrew in 1992. GIS not only revealed the
spatial pattern of hurricane damage, but also revealed its
connection with poor construction and lax building inspections which added significantly to the damage. Their work
earned the Pulitzer Prize for the Herald and introduced
journalists to the discovery qualities of GIS and cartographic analysis. Since 1992, print and broadcast media in
San Diego, Charlotte, Providence, Philadelphia, Chicago,
and Washington have been among the numerous news outlets to employ GIS and mapping to examine such topics as
school busing, lead poisoning, property assessments, drunk
driving, and the Florida ballot controversy in the 2000 presidential election.
A properly selected and constructed map is an indispensable tool for any journalist addressing the questions of
where and why. It is important to understand what type of
map works most effectively in an article and what form of
data is most appropriate for conveying the message. A good
map is a visually striking, highly efficient means of communication, if principles of map design and data presentation are observed.
Location can be defined in absolute and relative terms,
and maps effectively convey both. A news article utilizing the visual qualities of a map enables the reader to see,
for example, the size and location of Iraq relative to Israel,
Saudi Arabia, and Syria, and to better understand the results
of U.S. military activity in Iraq. Mapping the location of
the Kurdish concentration makes it immediately apparent
why Turkey closely monitors events in northern Iraq. More
locally, a map displaying the proposed path of new power
lines in a city tells readers whether their neighborhood is to
be affected. A map depicting a spatial cluster of robberies
tells readers not only the exact location of the crimes, but
also how close the problem is to their residence. To borrow
from the old cliché, if a picture is worth a thousand words,
maps are worth many more.
Mapping information can often provide answers to a
second important question: why? Effective maps demonstrate clusters or other spatial concentrations which help
to explain why events or phenomena occur where they do.
This ability to display spatial patterns makes the map a far
more effective means of communication than a list or table
of information by location. Lists require the reader to have
a well-developed mental map of the areas being described.
For example, only a small portion of the reading public has
the ability or knowledge to recognize the meaningful spatial patterns in the alphabetized list of corruption convictions shown in Table 1.
In contrast to an alphabetized list, a map of the same
information reveals patterns of corruption in the continental
United States that suggest possible reasons why this crime
occurs more frequently in some states rather than others.
Many of the states in the cluster spanning from New York
to Illinois have long histories of urban corruption synonymous with big city machine politics. Is this tradition still at
work? The swath of public corruption convictions along the
U.S. southern and coastal border raises the specter of a drug
connection. Lastly, the lack of public corruption in northern New England and much of the West is striking. Are
officials in these regions more honest than elsewhere? If so,
why? Maps reveal patterns and raise questions which are
virtually indiscernible in an alphabetized list. These inherent qualities invariably make their use far more effective in
telling a story.
Selecting the Appropriate Map Technique
While maps may greatly enhance a message, selecting the
proper type of map to display data is crucial to their effectiveness. Among the cartographic techniques available to a
writer, choropleth, dot distribution, graduated symbol and contour (isoline) maps are the most common and easily
understood by readers.
To determine which of these forms best fits an article,
journalists who have used maps effectively in the past have
considered three criteria: scale, geographical unit and the
discrete or continuous character of the data surface. Scale
refers to the amount of local detail the writer wishes to
display on a map. The map scale increases proportionately
to the local geography displayed. Thus large scale maps
display a small amount of the earth’s surface, but in much
greater detail than small scale maps. Conversely, a global
map would be considered a small scale display because,
although it portrays a large surface, very little detail can be
communicated about any particular location. Each of the
map types illustrated in Figure 2 varies in its effectiveness
as a large or small scale map. Graduated symbols are particularly problematic in smaller scale formats. There is a
tendency for the symbols to overlap one another to such an
extent that they obliterate the pattern on the map. Dot distribution maps are better suited to larger scales. On small
scale maps, such as a global or national depiction, there is
insufficient space to avoid severe over-lapping of the dot
symbols.
Journalists have used contour and choropleth maps frequently in their work because both map types are effective
in large or small scale displays, are sufficiently familiar to readers and usually contain patterns that are easily
discerned.
The contour, or isoline, map is especially familiar to
readers of the daily weather map. In this type of map, isolines—lines of equal value—are used to communicate the
continuous change in values across an area. In an isoline map the reader is able to determine the quantitative value at
any point on the surface by assessing the distance between
contours and noting the values of these isolines. The key is
to recognize that contour/isoline maps are only suitable for
data that are geographically continuous, i.e., values which
change continuously from point to point within the area
displayed on the map. Examples of geographically continuous data include precipitation, temperatures, terrain and
population density. In each case, these data are based upon
points rather than areal units.
When a writer wishes to compare geographical units
such as states, countries or counties, the choropleth map is
the ideal means of communication. Choropleths are areas
of equal value, meaning that values are assumed to be the
same throughout a spatial unit and are limited to the boundaries of that territory. Choropleth values are therefore geographically discrete. They are geographically confined to
that spatial unit and are equal in value throughout the territory. A presidential candidate either wins a state’s entire
electoral allotment by carrying a plurality of its popular
vote, or receives none if he/she fails to do so. Given these
discrete qualities, a choropleth map has historically been
the most effective means of communicating U.S. presidential election results.
Proper Map Construction
Choropleth maps have been used often in news reporting,
but not always correctly. Among the most common misuses
has been the failure to properly shade the geographical units
displayed on the map. In constructing a choropleth map,
the writer must remember that a reader’s eye will naturally
gravitate towards the shade or color of greatest intensity,
assuming (correctly) that intensity is related to quantity.
Choropleth maps become unreadable or misleading if this
principle is not observed. Consider the map in Figure 3.
This map in Figure 3 fails to use a logical monochromatic scale, leading the reader to assume that the greatest
concentration of guns available to children is in mid-Southern states. In fact, states in the Southwest and Southeast
are far more dangerous to children. This misimpression
was created because the shade depicting the greatest value
was among the lightest on the map, while mid-level values
are shaded much more intensively. Whether in gray tone
or color, it is imperative that a progressive monochromatic
scale be directly related to the values being mapped. It is
also important that the shade patterns used in a choropleth
map be easily distinguishable. In Figure 3 it is not immediately apparent, for example, that Maryland and New Jersey have markedly different numbers of guns available to
children.
There are other principles of good map design that are
applicable to an effective choropleth map. In addition to an
effective map title, legends must also have a clear title to
indicate what numerical units are being displayed on the
map. In Figure 3 no legend title was provided, leaving the
reader to wonder if the values represent numbers of guns or
children. A close reading of text should not be necessary to
make that distinction. An effective choropleth map should
be able to “stand alone” in it readability. Applying these
principles to Figure 3, its revised continental U.S. version
might appear as Figure 4.
A final and highly important consideration in using maps
for news reporting has been the need to recognize the difference in the message produced by data in absolute versus per
capita form. A map is a highly effective means of answering the question “how much is found at each location?” but
the spatial variation in quantity can change significantly according to whether absolute or per capita values are used.
The failure to recognize this distinction can produce maps
that convey little more than population size. For example,
the spatial pattern of corruption convictions shown in Figure 1 may primarily be a function of the population sizes of
each of the forty-eight continental states. This is often the
case when mapping the absolute amount of a phenomenon.
In some instances absolute volume is the message of the
story. But consider the different message produced by reexamining the corruption story through a map of the data in
per capita form (Figure 5).
California, which has more corruption convictions
among its public officials than any other state, virtually disappears in significance when its population size is taken
into account in Figure 5. The populations of the Dakotas
and Montana are among the smallest in the United States,
but apparently the proportion of their public officials who
were convicted for corruption was among the highest in the
country. In 2005, much attention focused on the effectiveness of the government’s response to damage from Hurricanes Rita and Katrina. Figure 5 might lead to interesting
speculation as to whether there is any connection between government hurricane response and the high concentration
of per capita official corruption in Louisiana and Mississippi—a pattern that is only revealed by mapping the data
in relation to the size of each state’s population.
In 2007, there were a number of commercially available
mapping packages, products developed by ESRI being predominant. In addition to using them, modern journalism
enterprises had ample opportunities to employ graduates of
geography and Geographic Information System programs.
There was an exponential growth in the number of individuals with GIS and computer mapping skills, and the
news media were well-positioned to take advantage of their
capabilities.
Further Reading
Bosse, David (compiler). Civil War Newspaper Maps, A Cartography of the Northern Daily Press. Westport, CT: Greenwood Press, 1993.
Herzog, David. Mapping the News. Redlands, CA: ESRI Press,
2003.
Monmonier, Mark S. Maps with the News: The Development of
American Journalistic Cartography. Chicago: University of
Chicago Press, 1989.
Robert M. Pierce