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PIXELS AND CENSELS: PUTTING PEOPLE IN THE PICTURE 
Robert W. Marx* 
Chief, Geography Division 
U.S. Bureau of the Census 
Washington, D.C. - U.S.A. 
ISPRS Commission VII 
The Geography Division, one component of the United States Bureau of the Census, developed the TIGER System to 
automate the full range of cartographic and geographic support processes necessary to serve the data collection, 
tabulation, and dissemination needs of the 1990 decennial census. In doing this, the Geography Division provided a 
new “tool” that could support the cartographic and geographic requirements of all the other statistical programs at 
the Census Bureau — the economic, agriculture, and governments censuses; the numerous monthly, quarterly, and 
annual sample surveys; and the analytical needs of those staff members using geographic information system (GIS) 
technology to study the results of its statistical programs. The Census Bureau also has made this new tool available 
to support the work of other Federal agencies, state and local governments, academic institutions, and those 
commercial organizations that share an interest in GIS applications. 
Although the TIGER data base is not a GIS in the traditional context of such systems, the way in which the Census 
Bureau collects and tabulates data is by “polygon.” The geographic structure of the 1990 census, as documented in 
the TIGER data base, provides machine-usable geographic units (polygons) similar to the ones used by the people 
collecting and studying soils or land use/land cover information. More importantly, in creating its “people 
polygons,” the Census Bureau routinely uses as the boundaries for its geographic units the same earth surface 
features most people appear to want — and that many already include — in their GIS: streets, roads, streams, 
railroads, governmental unit boundaries, and so forth. Thus, the TIGER data base is a very valuable source of 
information that can form a critical component of a GIS. 
In a GIS environment, a data analyst using the TIGER data base can examine numerous geographically distributed 
data sets in the context of the governments responsible for managing an area, in the context of the characteristics of 
the people who occupy the land, in the context of those people’s homes and farms, and in the context of the businesses 
and industrial activities that support the economy. The Census Bureau completed release of the second TIGER 
Extract product — the Precensus TIGER/Line files — in February 1990; they contain more than 19 gigabytes of 
geographic information that can be used in a GIS. For most data users, the quickest and easiest way to start using 
the TIGER/Line files is to obtain, from a vendor, software appropriate for the specific task envisioned and for the 
computer hardware available in the office where the files are to be used. 
To prepare for the future and the ongoing maintenance of the TIGER data base, the Census Bureau is participating 
in several experimental programs with other Federal agencies and some state governments to evaluate possible 
methodologies for updating the feature and geographic entity information. The approach finally selected probably 
will be some combination of cooperative programs and traditional approaches. 
KEY WORDS: TIGER, 1990 census, GIS, polygons, census geography. 
Many years ago, Miguel de Cervantes recognized the 
value and intrigue of maps by having his creation, the 
crazy but occasionally profound dreamer Don Quixote, 
exclaim that “...in a map, one could journey over all the 
universe, without the expense and fatigue of traveling, 
without suffering the inconveniences of heat, cold, 
hunger, and thirst.” 
Even in his wildest dreams, Don Quixote could not have 
conceived of the maps people are creating these days. 
Using computerized mapping and geographic infor 
mation system techniques, people can create map 
visualizations that range in coverage from the vastness 
of outer space, through the familiar range of small- and 
large-scale maps, to the largest end of the map scale 
continuum where humans constantly strive for greater 
and greater detail, which demands greater and greater 
accuracy in observation and measurement. The fore 
going leads, somewhat inexplicably at this point in the 
paper, to a discussion about tigers. 
BACKGROUND 
People normally visualize a tiger as a large, yellow, cat 
like animal with black stripes. The TIGER to which this 
paper refers is an altogether different creature. It is an 
acronym that the United States Bureau of the Census 
* Robert W. Marx has been responsible for planning, 
administering, and coordinating all geographic and 
cartographic activities that affect and support the 
statistical programs of the Census Bureau since April 
1983. Most significant among these activities has been 
the development of the TIGER System. 
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created to refer to its new computerized geographic 
support system: the Topologically Integrated Geo 
graphic Encoding and Referencing System (Marx, 1986; 
U.S. Bureau of the Census, 1985b). 
The Goal 
The Geography Division, one component of the Census 
Bureau (U.S. Bureau of the Census, 1988), developed the 
TIGER System in response to a major goal the agency 
set in 1981: 
To automate the full range of cartographic and 
geographic support processes necessary to serve the 
data collection, tabulation, and dissemination needs 
of the 1990 decennial census - the Bicentennial 
Census of the United States. 
The charge to the Geography Division included having 
the initial set of cartographic and geographic products 
from the TIGER System ready when the preparatory 
field activities for the 1990 census began in early 1988. It 
also included providing other geographic services and 
products at specified times throughout the 1990 census 
cycle (Marx, et al., 1990b). This charge gave the 
Geography Division six short years: 
• To design, develop, test, and implement a computer 
data structure like none in existence before (Kinnear, 
1987); a data structure that would handle both the carto 
graphic and geographic tasks for which the Geography 
Division is responsible within the Census Bureau. 
• To identify, procure, install, and - most significantly 
- learn to use, the graphic work stations, computer- 
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