DATA, MAPS, AND MORE AT THE U.S. CENSUS BUREAU INTERNET SITE

Abstract

"Government has no more powerful tool to serve customers than information technology. It is central to the Administration's goals of rebuilding the economy and improving the quality of life for Americans."

Vice President Al Gore's National Performance Review
September 1994

Introduction

Historically, the Census Bureau has been at the forefront of developing and using state of the art technology to accomplish its Constitutional mandate to conduct a population and housing census every ten years, and then disseminate the resulting information quickly and accurately (Anderson 1988). Recent developments from the 1990 census, such as the TIGER data base and the early use of CD-ROM technology for data dissemination, have facilitated governmental, commercial, and research applications well-beyond the scope of census-taking. These developments, coupled with the more recent and widespread diffusion of the Internet, may provide a major impetus to the ongoing development of a robust national spatial data infrastructure.

The Census Bureau's use of the Internet as a tool to disseminate data in a more timely fashion, publicize Bureau programs, and foster discussions and research, is part of a larger effort among federal agencies to electronically document and deliver data to the public. In this context, and encouraged by the Clinton Administration's National Performance Review, the recent and widespread diffusion of the Internet promises to play an increasingly important role at the Census Bureau.

The Census on the Web

The World-Wide Web, developed in 1989 by CERN labs in Geneva, is a hypertext system which links images, sounds and text, collectively known as hypermedia. A user "navigates" the World-Wide Web, traveling from page to page, and browses information via mouse "clicks" on text and images. Alternative key pad methods of selecting a link are used for non- graphical browsers. The Census has also set up gopher and file transfer protocol (FTP) sites which can be reached through their own protocols and through the home page.

At the Bureau's home page, one finds a wide and increasing variety of links to census and survey data, geographic files, data look-up services, and other Bureau information. Links to other Internet sites carrying census-related information are continually being updated. The Census Bureau home page, like other Internet home pages, will likely go through many visual and functional transformations based on technical advancements, customer feedback, and the marketing dictum to keep things novel.

The Census Bureau's development of a public Internet site was initially dependent on the ability to ensure security of the Census Bureau's internal computer network. A protected firewall was established by the Census Bureau to separate the internal network from the Internet or external network. Additional security measures and encryption techniques are being investigated to ensure security and confidentiality of sensitive data.

Electronic Mail

Along with faxing, email is used at the Census Bureau to distribute information to customers who prefer electronic mail over standard postal service "snail mail" (Morton 1995). Advantages of electronic mail distribution include timeliness, convenience, lower costs, "less paper", and less likelihood of getting lost or damaged. However, while the Internet helps in the distribution of information, many more Census Bureau customers have access to fax machines and printed reports than have access to electronic mail. The Internet remains an alternative to and not a replacement of other conventional means of distribution.

Internet mailing lists provide a forum for discussion on selected topics. The Bureau administers the GeoWEB mailing list which fosters discussions on projects seeking to develop shared geographic resources, for example mapping interfaces, geospatial data, metadata, and data archives on the Internet. One such project is the TIGER Mapping Service discussed later in this paper. There are approximately 780 subscribers who comprise the virtual community of the GeoWEB list.

Statistical Data and Data Retrieval Tools

The Census Lookup consists of a series of hierarchical forms which prompt the user for the type of information needed. The forms allow the user to request data for various levels of legal and statistical geography including state, county, census tract and metropolitan statistical area. For example, through forms, the user can query the number of persons per households for Redlands, California. The Census Lookup returns the following data table:

	Current Level: State--Place

	Redlands city: FIPS.STATE=06, FIPS.PLACE90=59962

	PERSONS IN HOUSEHOLD
	Universe: Households
	1 person			5329
	2 persons			7020
	3 persons			3796
	4 persons			3437
	5 persons			1595
	6 persons		        528
	7 or more persons	  	425

Another tool for obtaining on-line Census data is DataMap . This tool employs the concept of an 'imagemap' - a clickable image of the United States - to provide state and county profiles and population estimates. Imagemaps provide a spatial, intuitive method for obtaining geographically referenced data. The user clicks on a state and an image then comes up of that state and its counties. The user then clicks on a county to get the county profile. Information available with DataMap was taken from the 1994 USA Counties CD ROM, which users can order over the Internet. Additional census and non-census data could easily be added or linked to these image maps. While the DataMap interface requires a graphical browser, the data it accesses can be downloaded using any browser.

Other statistical data files available at the Census Bureau Internet site using any browser include:

• Population Data
• Statistical Abstract of the United States
• U.S. International Trade Statistics
• Continuous Measurement Public Use Microdata
• County Business Patterns
• County and City Data Book (Top 77 City Rankings)
• Financial Data for State and Local Governments and Schools.

Geographic Data

Users also can download point files and boundary files of varying formats extracted from the TIGER Data Base. Files exist which include the following geographic entities:

• 1990 State (ST)
• 1990 County (CO)
• 1990 Minor Civil Division (MC)
• 1990 Census Tract/Block Numbering Area (TR)
• 1990 American Indian Reservation/Alaska Native village
• 1990 Alaska Native Regional Corporation (AN)
• 1993 Metropolitan Areas (MA)
• 103rd Congressional District (CD)
• ZIP Code centroids

As part of the effort to create better interfaces to Census data, the experimental TIGER Mapping Service, which requires a graphical browser, allows users to view 1992 TIGER/Line® files over the World-Wide Web by creating maps on-the-fly. This service is part of the greater GeoWEB project, started in May of 1994 as a joint venture between staff at the Census Bureau and the University of New York at Buffalo, though there are now participants world-wide. The GeoWEB, in conjunction with the Alexandria Project and the FGDC, explores methods of creating a spatial data clearinghouse as envisioned by the National Spatial Data Infrastructure (Nebert 1994).

The TIGER Mapping Service interface experiments with using the World-Wide Web as a source for custom maps from a single data source. The user can zoom, pan, or directly enter new map coordinates to navigate to different areas in the United States. Maps show water features, roads, military sites, and city and county boundaries. The maps currently lack text, although basic labeling is a planned enhancement.

Many of these map interface developments as well as the boundary and point files available are, in large part, a by-product of efforts to replicate on the Internet many of the software capabilities of the recently released LandView II product. The development of this public domain mapping software by the Environmental Protection Agency, in conjunction with the National Oceanic and Atmospheric Administration and the Census Bureau and driven by public access legislation, links and displays environmental, socio-economic, and demographic data using an extract of the TIGER data base. LandView II software can perform simple panning, zooming, and feature selection, link geographic and attribute data, perform limited geocoding, calculate distances and radius data aggregation, create on-the-fly thematic map displays, and a number of other capabilities. A demonstration version of this software can be obtained from the Census Bureau FTP site at ftp://ftp.census.gov/pub/tiger/lvdemo/lvdemo.zip.

Conclusion

Future uses of the Internet include electronic publication, data distribution and interchange, custom generation of products, providing user specified thematic map displays of census data, and enhancing census field operations. These uses may lead to a fundamental change in data collection and distribution methods by the Census Bureau.

Security issues are of central importance to the Census Bureau as it investigates the broader use of the Internet for future census programs and processes (e.g., address list sharing between local governments, the USPS and the Census Bureau, protecting credit card information of customers ordering census products electronically). Ensuring confidentiality of protected data while expanding data access remains a major and constant concern. An FGDC sponsored conference on Data Security will be held in April 1995 to address some of these issues.

Although the Census Bureau envisions a day, in the not too distant future, when most data will be disseminated electronically, we are still mindful of the many customers not connected to the Internet. The role of government in the emerging national information infrastructure must establish a careful balance between efficiency and access.

Census Bureau URLs