Appendix D: The Pennsylvania Geographic Information System (GIS) Program
The Pennsylvania GIS Program
The Pennsylvania Department of Health, Bureau of Epidemiology, Environmental Health Epidemiology, Health Assessment Program has developed the following program to use geographic information system (GIS) information to determine the proximity of child care facilities to facilities that use or generate hazardous materials.
Sources of Data
Esri open source data
- Topographic maps and rooftop aerials.
U.S. Environmental Protection Agency (EPA) Envirofacts
- Environmental sites: EPA brownfields, EPA National Priority List sites, and Toxic Release Inventory data.
- Resource Conservation and Recovery Act of 1976 (RCRA) Small Quantity Generators (SQG): dry cleaners, print shops, machine shops, laboratories, and furniture manufacturing and restoration.
Pennsylvania Spatial Data Access (PASDA)
- Pennsylvania Department of Environmental Protection sites and facilities: land recycling/brownfield sites, landfills, storage tank locations, air permit facilities, municipal waste generators, and Environmental Justice locations.
Pennsylvania Department of Public Welfare (PADPW)
- PADPW open child care facilities.
- Department of Defense (DOD)
- Formerly used DOD sites.
- Department of Energy (DOE)
- Formerly used DOE sites.
- U.S. Census
- Census maps and data, including block and census track locations
- The American Community Survey — a yearly survey that provides information about our nation and its people.
To determine the closeness of child care centers to environmental sites and RCRA small quantity generator (SQG) facilities, PADOH uses ArcGIS 10.0. The locations of the open child care facilities, environmental sites and EPA RCRA reporting facilities are geocoded by address or latitude and longitude coordinates in ArcGIS. Two analysis procedures are then performed in ArcGIS. The first is a “buffering” analysis that allows for setting a radius or buffer around the facilities. PADOH uses half the size of a typical city block (or 200 feet) to estimate the buffer distance from the SQG to a child care center. For other sites, including brownfields and NPL sites, PADOH uses an initial search buffer of 1/8 of mile. Next, an “intersect” analysis is performed to overlay the buffered child care locations with the environmental site data and SQG locations.
Based on these analyses, ArcGIS identifies a list of sites and facilities located within the search radius from the child care centers. For the SQG, the locations of co-located facilities are confirmed via ArcGIS rooftop mapping, to determine if the child care centers and waste generators potentially share a wall, and then by Google Street View. This additional step using Google Street View helps to determine if a facility was located across the street, on a different block or potentially sharing a wall as well as determining misidentifications.