248 A HISTORY OF AMERICA IN 100 MAPS
As shown on the previous page, the physician
Abraham Verghese used maps to understand the
outbreak of AIDS in his rural community of Eastern
Tennessee. At the same time, Pensylvania State
University geographer Peter Gould used early
digital techniques to map from 1982 to 1988 the
geographical distribution of HIV infection at two-
year intervals. Gould organized the data into what
geographers refer to as “heat maps,” showing
the spread of the epidemic from cities to the
entire nation.
To capture the soaring rates of the epidemic,
Gould measured the incidence of the disease not
incrementally, but in qualitative shifts. Areas with
the lowest rates of the outbreak are marked in blue,
with each successive color marking a level of infection
that is seven times greater than the last. In this regard,
Gould felt restrained by his flat, two-dimensional
representations. He imagined a more powerful
visualization in three dimensions, one that would
accurately capture the magnitude of the epidemic
in urban centers by showing a vertical measure
that dwarfed its incidence elsewhere. This type of
geographical modeling was well established within
a few years, as shown in the 2001 map of labor in the
meat processing industry on page 252.
Seen in sequence, the maps demonstrated the
pervasive and national threat of HIV by the late 1980s.
Gould noticed that the virus initially exploded in
urban areas, but when it inevitably spread beyond
the cities it did so not just by seeping outward as
epidemics had in the past, but also by leaping
across the country via air routes and along other
transportation corridors. In a context where every
infected patient is also a carrier, and where carriers
might live years before manifesting symptoms of the
disease, HIV was particularly difficult to contain.
But without a proactive and coordinated effort to
share information, Gould argued, there was little
hope of limiting the disease.
To bring home the seriousness of the situation,
Gould designed a final map projecting the extent of
the epidemic by 1990. Though his worst predictions
were not realized, the death toll of AIDS continued.
By 2000, it had killed 400,000 Americans, and nearly
nineteen million people worldwide. Like Verghese,
Gould turned to the map to uncover paths and
patterns of AIDS that were otherwise invisible. And
both men used maps not just to document its
history, but to guide future decisions and policies.
However flawed, these maps powerfully facilitated
spatial thinking.
Peter Gould, number of AIDS cases
in 1982, 1984, 1986, 1988, 1990
(published 1999)