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Spring 2005
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GIS Helps Homebuyers, Business Ventures, Nonprofit Organizations, and Local Governments

U.S. Census Bureau's American FactFinder Provides Easy Access to a Wealth of Data

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A thematic map of median household income for 60614 showed a census tract near one of Jenkins' possible restaurant locations with a median income of $127,031.

The United States Census Bureau understands that there are hundreds of thousands of people who have a great idea yet need detailed statistical and geographic information to help in analysis and decision making. To help these people, the Census Bureau developed the American FactFinder Web site (, which has become the Census Bureau's primary Internet tool for access to official and current demographic, economic, and geographic data. American FactFinder generates online customizable reference and thematic maps for users to visualize detailed information. Using only the default settings, users can link data to mapped geographic areas to create more than 18 million maps.

American FactFinder regularly helps people make informed decisions. Many local governments already make extensive use of Census Bureau data to identify the locations of target populations for services and to allocate facilities and resources to serve target populations most effectively. Nonprofit organizations frequently access language statistics to determine areas where information should be distributed in a language other than English. Potential homebuyers compare housing values and high school graduation rates across different communities to make an informed home buying decision. Using the Internet, the Census Bureau returns the valuable data it collects to the individuals and organizations that provide it, supporting and enhancing their business, policy, and personal decision making.

American FactFinder thematic maps, reference maps, and geographic address searching capabilities were developed using ArcIMS and ArcSDE technology. Esri was selected for this project because of its comprehensive approach to GIS requirements across the Census Bureau. ArcSDE is utilized for the retrieval and management of all spatial data. ArcIMS provides the interactive mapping capabilities used to search for and visualize data with spatial components through Web browsers.

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American FactFinder's reference map for 60614 illustrates geographic boundaries along with selected features, such as streets and major highways, helping the user better visualize the location.

To support data visualization and site navigation, American FactFinder provides a range of geospatial features, including map-based geographic selection to support data queries, reference maps to visually identify survey boundaries, thematic maps to aid data visualization, and geocoding services to support search-by-address queries.

Maps displayed in American FactFinder are drawn using an Albers equal area conic projection, which is predominantly used to map regions of large east-west extent, in particular the United States.

American FactFinder's mapping capabilities are supported by more than 1,000 layers in the ArcSDE spatial database. Detailed layers display actual geographic boundaries. Projected layers are needed for the smallest map scales in American FactFinder to minimize distortion in representing the three-dimensional earth in a two-dimensional space. Generalized layers are used to display appropriate features and boundaries at various zoom levels. American FactFinder's 140 AXL files reference multiple layers in the ArcSDE database and specify which layers to use for certain zoom levels.

Hypothetical Organic Food Restaurant: How to Target Potential Customers

To help show exactly how American FactFinder works, this article proposes the following hypothetical, nonetheless detailed, step-by-step example of how analyzing the comparative merits of several potential restaurant locations in Chicago, Illinois, could be made easier using Census Bureau thematic and reference maps.

Let's say that late in 2003, Howard Jenkins noticed the lack of organic food restaurants in Chicago and decided to evaluate potential business opportunities in this market. Jenkins himself was an excellent cook and decided to seriously consider opening a restaurant that featured organic ingredients. For his new business to be a success, Jenkins knew that his restaurant would need to be located in a high-income area because of the high cost of organic ingredients. He found several potential restaurant locations available in various Chicago area ZIP Codes, but he was unsure of which site locations would be in closest proximity to the appropriate clientele.

Jenkins' small business "how-to" guides touted using U.S. Census Bureau statistics for targeting potential customers, analyzing site locations, assessing the competitive environment, and forecasting potential growth. His local librarian then referred him to the American FactFinder Web site.

Jenkins began his research by looking for basic demographic information for each of the Chicago area 5-digit ZIP Codes where restaurant locations were available. He started with American FactFinder's Fact Sheet, which gave him basic information on each of the areas he was considering—including the population count, median household income, education level, and average household size.

Jenkins then decided to try looking at the data in map format, to more easily identify patterns across multiple geographic areas. Using links from the Fact Sheet to thematic maps of population density, median age, household income, and average household size, he noticed significant differences in median income across the various ZIP Codes under consideration. He pinpointed the 5-digit ZIP Code tabulation area with the highest median income in the group he was considering: 60614. According to the 2000 Census, ZIP Code area 60614 had a median annual household income of $68,324, significantly higher than the national median of nearly $42,000. Further analysis also showed that the median age in 60614 was 31.0 years—much younger than the national average and a desirable demographic indicator since younger adults tend to eat out more often than older people.

To help convince potential lenders, Jenkins downloaded the thematic maps in PDF format for insertion into his business plan. He also downloaded the associated data into Microsoft Excel format for further offline analysis, allowing him to integrate Census Bureau data with industry specific data obtained from restaurant trade associations.

Analyzing Site Locations

Jenkins' next task was to choose the specific restaurant location within his selected ZIP Code. Because the Census Bureau has data available for more small geographic areas than any other survey organization, Jenkins was able to further analyze median household income in the immediate neighborhood of each potential restaurant. Using American FactFinder's search-by-address tool, he displayed a map of ZIP Code area 60614 subdivided by census tract, each of which included an average of only 4,000 inhabitants. American FactFinder maps include streets and major highways in addition to demographic data—allowing Jenkins to easily find and compare the characteristics of possible restaurant neighborhoods.

Jenkins decided he'd struck gold when the map of median income (TM-P063) for 60614 showed a census tract (#720) near one of his possible restaurant locations with a median household income of $127,031.

Assessing Competitive Environment

Jenkins next visited American FactFinder's Business and Government page to learn more about the competitive environment of the restaurant industry in the Chicago area. Restaurant industry highlights—including data on annual revenues, number of locations, and number of employees-were available from the 2002 Economic Census Quick Reports. Jenkins analyzed Cook County, Illinois, data and then narrowed his search to look at local trends by individual ZIP Code for the restaurant industry. Possible restaurant offerings were developed using statistics on full-service restaurants. Data in the County Business Patterns showed the growing state of the restaurant business in Cook County, Illinois.

Forecasting Future Growth

Another important factor in Jenkins' hypothesized restaurant site selection was the forecast of future growth based on population trends. Jenkins wanted to see how population for cities and towns within Cook County had changed between 2000 and 2003 to identify trends affecting his potential site. American FactFinder supplied a thematic map from the Population Estimates program that illustrated population growth in the outer suburbs of Cook County between 2000 and 2003 and population decline in the city of Chicago in the same time period. Jenkins used this information to substantiate his forecast of future revenue growth for his planned restaurant. Having access to Census Bureau information gave Jenkins the answers he needed to create his blueprint for success.

For more information, contact Marian Brady, Data Access and Dissemination Systems Office, U.S. Census Bureau (e-mail:, or visit American FactFinder (

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