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Geodemography


Susan Haynie
Ph.D., Demographic Consulting,
Inc., USA
shaynie@geodemo.com


Shuming Bao
Ph.D., China Data Center,
The University of Michigan USA
chinadata@umich.edu

INTRODUCTION
The term census “originally referred to the enumeration and registration of people and property, often for the purpose of taxation.” (Peters & MacDonald, 2004). The knowledge gained from a census about the numbers of people, their characteristics, and their housing is of critical importance to governments, businesses, researchers and service providers. This paper describes the availability of Census data in the U.S. and China, and the advantages of using GIS and geo-spatial analysis to help analyze that data.

Geodemography, the linkage of geographic and demographic information, is a powerful tool, useful for many applications. Applications of geodemographics are discussed, particularly those relating to business and commercial applications.

Specialized geodemographic tools (Marketing Information Systems) make data access easier. New user interfaces can automate analytic projects, report packages, and thematic maps of census data. The result is that more end-users can easily access the information they need. These software and data products are customizable to the end-user’s experience level and data needs. Extensive GIS training is not required to retrieve the automated results. This leads to greater efficiency and cost savings.

Geospatial analysis can create new information. In the past, the reporting of census information was typically limited to standard administrative units. The power of geospatial analysis allows data to be retrieved for custom geographic areas (for example, a one km radius around a store, or a buffer along a transportation corridor.) In this new era of electronic data, the internet, and GIS, geospatial tools have removed the limitations of printed reports and standard administrative boundaries. The result is a fundamental change in how Census data can be utilized.

CENSUSES AND GEODEMOGRAPHICS
A census is used to collect measures of characteristics of populations (“demographics”). Geodemography is the linkage of demographic data with spatial location. Examples of demographics include how many persons are in specific categories of age, race, ethnicity, education, occupation, etc. Demographics can also refer to housing characteristics, such as number of rooms in a residence, home ownership, housing value, and availability of utilities such as plumbing, electricity or telephones, etc.

Demographics about populations can be collected in a variety of ways. The most comprehensive collection of demographics is via a Census. Typically, a Census is conducted with the goal of counting every member of a population. Often conducted (and paid for) by a country’s government, a Census provides extremely valuable information for planning purposes.

This paper addresses Census information for two countries: People’s Republic of China (China) and the United States (U.S.). Both countries have a history of censuses collected by the national government. The first U.S. Census was in 1790, and has been conducted every 10 years since then. China’s recent population censuses include 1953, 1964, 1982, 1990 and 2000.

A critical aspect of Census data, whether in China, the U.S., or other countries, is that the data is typically reported as geographic totals. Data about individuals is usually not publicly available (at least not in a form that can identify specific individuals). Rather, it is summarized to a variety of geographic levels. Table 1 lists some of the geographic levels reported in the U.S. and Chinese Census data.