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Geographic Information System (GIS)
A Geographic Information System (GIS) is the high-tech equivalent of a map. Unlike traditional paper maps, which are usually made to fit a single purpose and, once printed, go out of date fairly quickly, a GIS may be used for any number of different purposes and may combine countless sources of data that can be manipulated and updated at any time.
A GIS is a computerized tool used to map and analyze the spatial relationships between the earth’s features and events. A typical GIS set-up includes a high-powered computer, specialized mapping software and one or more digital databases containing information about a particular feature or event along with geographic information about where that feature or event is located on the earth. An informative presentation on geographic information systems is available at the U.S. Geological Survey (USGS) website.
Using a GIS, researchers can relate otherwise disparate data on the basis of common geography, creating new information from existing data resources. “Hidden” in most data is a geographic component: an address, postal code, census block, city, county or latitude/longitude coordinate. GIS software allows researchers to explore and analyze data by location, revealing patterns, relationships and trends that are not readily apparent in the text of the data itself.
For example, a GIS can be used to map where people diagnosed with a particular disease live. A good example of using GIS for this type of research is illustrated by the National Cancer Institute’s GIS website. Mapping diseases can help epidemiologists recognize disease trends or outbreaks. Additionally, a GIS can be used to overlay the locations of people diagnosed with a disease with the locations of possible causes of that disease. GIS technology, used in conjunction with rigorous epidemiologic analyses, can help epidemiologists to link together diseases and their causes.
This is the application for which the Environmental Health Investigations Branch (EHIB) has developed its Geographic Information System. With its GIS, EHIB has analyzed data on environmental exposures, such as automobile traffic, pesticides and drinking water, and human health outcomes, such as cancer and respiratory problems. EHIB maintains GIS workstations that enable its staff of specialists to map and analyze spatial correlates of case and exposure data. EHIB's GIS provides access to and utilization of a wide range of digital geographic data from both commercial vendors and public domains including Federal, State and University organizations.
EHIB has also realized the power of the World Wide Web for exchanging GIS data and functions to its partners. Over the coming years, stakeholders within the California Department of Public Health as well as the California public will witness a sharp increase in the availability of enterprise GIS offerings through our web portal. Check this page periodically to see about changes in our GIS infrastructure.
Papers
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California's New Environmental Health Tracking Programs
(04/01/2004)
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In the wake of 9/11, renewed resources and attention have been given to the nation's public health infrastructure, especially in the areas of surveillance of acute infectious illnesses and monitoring the...
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Changes in the spatial pattern of low birth weight in a southern California County: The role of individual and neighborhood level factors
(05/23/2002)
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Individual-level maternal risk factors have been able to explain only a small proportion of low birth weight (LBW) births in the US to date and neighborhood-level factors have not been recognized as...
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Hierarchical modeling of spatio-temporally misaligned data: Relating traffic density to pediatric asthma hospitalizations.
(03/14/2000)
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Bayes and empirical Bayes methods have proven effective in smoothing crude maps of disease risk, eliminating the instability of estimates in low-population areas while maintaining overall geographic trends...
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Maternal Residence Near Agricultural Pesticide Applications and Autism Spectrum Disorders Among Children in the California Central Valley
(07/30/2007)
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Background: Ambient levels of pesticides ("pesticide drift") are detectable at residences near agricultural field sites....
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Pesticide Use in California: US/Mexico Border Region, Final Report
(03/14/2000)
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Analytical Procedures, Methodologies, and Field Protocols to Monitor and Determine Environmental Contaminants To assist the U.S....
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Post office box addresses: a challenge for geographic information system-based studies
(07/15/2003)
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Background: Geographic information system (GIS)-based health studies require information on the physical location of data points, such as subject addresses....
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Progress in Pediatric Asthma Surveillance I: The Application of Health Care Use Data in Alameda County, California
(07/01/2006)
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Introduction: The ability to conduct community-level asthma surveillance is increasingly crucial for public health programming and child health advocacy....
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Progress in Pediatric Asthma Surveillance II: Geospatial Patterns of Asthma in Alameda County, California
(07/01/2006)
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Introduction: As with many diseases, the epidemic of asthma among children over the past few decades has been shaped by a social and environmental context that is becoming progressively more evident....
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The California Environmental Health Tracking Program: New Online GIS Tools for Investigating Diseases and the Environment
(04/30/2008)
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Diseases, such as asthma, are related to environmental risk factors, which have a large spatial component....
Related Tools
- Geocoding
- Agricultural Pesticide Use Web Mapping Service
- Drinking Water Systems Geographic Reporting Tool
Related Projects
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Border GIS and LANDSAT Project: Pilot study of feasibility of using satellite imagery to predict cropping patterns in Imperial and Mexicali Valleys
-- In 1998, EHIB used satellite imaging methods to estimate the types of crops grown in the agricultural Mexicali Valley of Mexico and the land uses for this region....
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California Environmental Health Tracking Program (CEHTP)
-- California Environmental Health Tracking Program Improving Public Health With Better Information air quality asthma birth defects cancer carbon monoxide poisoning climate change drinking...
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Childhood Cancer - Etiologic Clues Using Geographic Information Systems
-- Little is known about the causes of childhood cancers, but there has been increasing public concern that environmental toxicants may contribute to the risk of developing this heterogeneous group of...
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Community Vulnerabilities and Resiliencies to Heat Waves
-- California has suffered a number of heat waves (HW) which have resulted in considerable morbidity and mortality....
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Exposure Insights Using GIS in a Case-Control Study
-- Little is known about the causes of childhood leukemia, but there is considerable public concern about the potential contribution of environmental toxicants....
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Geographic Information System (GIS) for the Border Region
-- Initiated in 2007, the Border GIS project inventories various types of environmental data for the Border region and assesses Environmental Health Indicators....
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Perchlorate in Drinking Water and Newborn Thyroid Function
-- Historic waste disposal practices at the Aerojet-General Corporation facility in Rancho Cordova contaminated some of that city's underground drinking water supply with perchlorate, starting in the late...
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Pesticide Use in the U.S.-Mexico Border Region
-- EHIB analyzed pesticide use data from 1991 to 1995 in Imperial and San Diego Counties, to investigate areas where potential pesticide exposures could occur in children living along the US-Mexico border....
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Regional Variations in Breast Cancer Rates in California
-- Geographic location is among the greatest predictors of breast cancer incidence, with more than a ten-fold difference among regions of the world....
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Testicular Cancer: Etiologic Factors
-- Although testicular cancer is the most common cancer in young males in the United States, and its incidence is increasing worldwide, not much is known about the etiology of this illness....