Mapping Socioeconomic Data Reveals Trends
In October 2006, the U.S. Census Bureau announced that the nation's population had reached 300 million people a number that has tripled since 1915. This milestone raises critical questions regarding where people live or don't live in the U.S. that help feed high-level decisions on where to allocate government resources on education, health and other services.
To put these and other vital statistics into visual context, the Center for International Earth Science Information Network (CIESIN), part of The Earth Institute at Columbia University, has created the U.S. Census Grids, 2000 Web site, an online resource that provides spatial data maps showcasing a wide range of socioeconomic characteristics of the population of the United States and Puerto Rico based on Census information from 2000. By converting the statistical units of U.S. Census data to a raster format a rectangular grid of values the U.S. Grids allows researchers to look at Census data in new ways, comparing or combining data for potentially greater insights and wider application.
"Even though our data refer to the year 2000, they do depict trends that are being covered in the media, such as the concentration of population along U.S. coastlines," said Lynn Seirup, CIESIN Staff Associate. Such information is critical to revealing trends that may affect government resource allocation and spending. For example, as more people move to locations along the country's coasts, they may be more vulnerable to natural hazards such as hurricanes and flooding. In addition to population and housing statistics, downloadable data and maps are available for approximately 35 different variables, such as the number of individuals living below the poverty line or the number of households without a vehicle. The raster format of the data allows analysis at a higher resolution for a larger area than is feasible using Census statistical units.
According to Seirup, raster format makes it easier to combine data to support social vulnerability analysis; for example, studying how particular social groups were affected by Hurricane Katrina. Calculating the number of households in a watershed or the number of elderly in a disaster zone is far easier with raster data. Using this format, the U.S. poverty maps are able to reveal critical information, specifically, that some of the poorest areas of the country are where there is less population density. Native American reservations are heavily poor, as are Appalachia and West Virginia.
Seirup, an expert at spatial data mapping, says she was surprised at how much the maps reveal about population trends. "I was particularly surprised at the map on housing age. The majority of housing units in the Midwest were built before 1970, while housing units in the South and West were built primarily after 1970. The differing growth rates within the U.S. are starkly evident from this map," said Seirup.
The CIESIN team hopes that the maps will promote the value of data spatial mapping for a range of uses, particularly in planning programs and budgets. "We need to educate people on the value of mapping socioeconomic data," said Seirup, who once worked for New York City's Office of Emergency Management. "The Census Bureau does an incredible job of making their information available but people still need help figuring out how to use that data. We hope that the gridded data will make this information more available to a new group of researchers and planners."
The data and Web site are products of the NASA Socioeconomic Data and Applications Center (SEDAC), operated by CIESIN. The U.S. Census Grids, 2000, are available at http://sedac.ciesin.columbia.edu/usgrid/