GIS Data Sources Thomas Talbot Chief, Environmental Health Surveillance Section Bureau of Environmental & Occupational Epidemiology New York State Department of Health
Outline Sources of Data Census, health, environmental, base layers Data Accuracy Data Sharing (NYS GIS Clearinghouse) GIS web services Street Address Mapping (NYS SAM)
US Census The US Census is mandated by the Constitution. The population is enumerated every 10 years. Results used to allocate Congressional seats, and government funding. The Census Bureau is responsible for the Census. The first census was taken in 1790, under Secretary of State Thomas Jefferson. For years between decennial census, the Census Bureau makes estimates using the American Community Survey.
US Census TIGER Files New York State - 2010 County - 62 Minor Civil Division (Town) 1,013 Census Tract 4,902 Block Group 15,241 Census Block 350,162
Census Geography, Albany County
Census Geography, City of Albany
Other Census Areas Census designated places Delmar, Slingerlands, Westmere Incorporated villages Voorheesville Altamont Cities Binghamton City ZCTA Native American Reservations School Districts Congressional Districts
Other Features in TIGER Transportation features (CFCC Codes) Streets & highways (with street number range & name Railroads Ferry Crossings Foot paths Airports Water features (rivers, lakes, streams, ocean) Other features (landmarks, parks, malls, power lines)
Decennial Census Basic demographic information Age Sex Race Ethnicity Number of Housing Units Group Quarters Household relationships
American Community Survey A large, continuous demographic survey 250,000 Households nationwide every month Housing unit address is the sample unit not people Produces annual and multi-year estimates of the characteristics of the population and housing
American Community Survey Sample of households. Census views it as producing characteristics distributions, NOT counts Produces information for small areas including tracts, block groups & population subgroups
American Community Survey
Multiple numbers for the same area Data Release Every Year Period rather than point estimates 2010 release for areas of 65,000 or more 1-year estimate (2009 collection) 3-year estimate (2007-2009 collection) 5-year estimate (2005-2009 collection) 2010 release for areas of 20,000 to 65,000 3-year estimate (2007-2009 collection) 5-year estimate (2005-2009 collection) 2010 for areas areas under 20,000 5-year estimate ONLY (2005-2009)
FTP S
FTP Site Provides Comma Separated Value (CSV) Files Data which can imported into spreadsheet, statistical or GIS software If you want to import census attribute data to your GIS you need to assign variable names and the select which variables and geographic areas you need. The census and others have developed programs for extracting data and naming the variables.
Health Data Vital statistics. Birth and death (ICD Codes) Cancer Incidence Congenital Malformations Alzheimer & Dementia Registry AIDS Infectious Diseases Hospital Discharge Data (SPARCS)
Exposure Registries Occupational Heavy Metals Registry Childhood Blood Lead Reporting System Radon Registry Volatile Organic Compound Registry Pesticide Registry
Environmental Exposure Sources Toxic Release Inventory Inactive Hazardous Waste Sites Municipal landfills Discharges to water (SPDES) Household measures of radon Soil sample data Drinking water contaminants Air pollution modeled and measured Contaminants in fish Power plants Contaminants in raw and finished drinking water
Base Layer Data and Other Streams, Rivers, lakes, wetlands Elevation Aerial Imagery Topographic Maps Soils & geology Land use / land cover Flood zones
US Census TIGER Files Topologically Integrated Geographic Encoding & Referencing Digital database developed to support Census s mapping needs. The data base defines the location and relationship of streets, rivers, railroads, and other features to each other.
Census Tracts Census tracts are small, statistical subdivisions of a county. Uniquely numbered in each county with a numeric code Census tracts average about 4,000 inhabitants Minimum Population 1,200 Maximum Population 8,000 31
Updating Census Tracts Census tracts are designed to be relatively permanent over time. Any changes are documented so data can be compared from decade to decade. Census tracts with more than 8,000 people are split into 2 or more tracts Census tracts with less than 1,200 people are merged with a neighboring tract Small boundary corrections are sometimes allowed as well. 32
Census Tracts are Merged as Population Decline below 1,200
Data Accuracy Attribute Accuracy Spatial Accuracy Temporal Accuracy Determine level of accuracy needed for project. Examples: How many people live within an 30 minute drive to an emergency room. Who lives within 250 feet from a hazardous waste site.
ACS Statistical Quality Impute missing data ACS products (sample) Reported at 90-percent confidence level Summary Files also have Standard Errors May affect uses of the data Denominators Regression analysis
The census does not always put populations in the correct census area. Merge these blocks before using aggregation tool From 2000 census 40
Census Enumeration Errors 831 persons living in Colonie Shopping Center 0 persons living in neighboring apartments
Intercensal Estimates are Unreliable example: several disease cases have recently occurred in this area, the intercensal Claritas estimate = 0 population New construction Census 2000 0 Persons 2008 Intercensal Estimate 0 persons 42
Temporal Accuracy TIGER Streets Real Property Points
Spatial Accuracy Census TIGER Files (2000)
New York ALIS Street Files (2005)
Data Sharing New York Stat Clearinghouse Model
Geographic Databases Framework Data Additional Base Data Land Ownership Transportation Surface Waters Boundaries Geodetic Control Elevation Ortho Imagery Flood Zones Wetlands Landcover Water Lines Sewer Lines Soils 47
NYS GIS Data Sharing Cooperative Government, NFP, Academics Contacts Feedback 48
Orthoimagery Program 4-Bands (R, G, B, and N-IR) 1-ft GSD in urban areas, +/- 4-ft 2-ft GSD in rural areas, +/- 8-ft NYC Specs 0.5-ft Color, +/- 2-ft All structures in Manhattan orthorectified Structures above 5-stories in outer boroughs orthorectified June flight for Manhattan Ground Sampling Distance (GSD) - distance between pixel centers
ArcGIS Provides Access to a Number of On-line Base Maps Example : World Street Maps
USA Topographic Maps
Adding a Web Map Service (WMS) to your Map NYS GIS Clearinghouse Orthoimagery http://www.orthos.dhses.ny.gov/arcgis/services/latest/mapserver/wmsserver?
Street Address Mapping(SAM) Create a statewide authoritative address point database to support next-generation 9-1-1 and other purposes
SAM Big Picture Next Generation 911 requires GIS data Huge range of needs for address data statewide Building to highest level requirements (i.e. 911) will support all lower requirements Not a re-addressing project; we re just mapping what you've got Address point data will Support 9-1-1 dispatch Be publicly available for widespread uses Support high-quality geocoding Contain no personal or sensitive information Contain unique IDs
61 Apartment Building Complex 70 Mc Carty Ave Building 1, Apt 1; Building 2, Apt 4; etc.
Homework Read: Chapter 3: Cromley & McLafferty, GIS & Public Health Mills JW, Curtis A, et al. The clearinghouse concept: a model for geospatial data centralization and dissemination in a disaster. Disasters, 2008 32(3): 467-479 Explore: US Census Web site: www.census.gov New York State GIS Clearinghouse: http//gis.ny.gov The End