Census Bureau Geographic Entities and Concepts Presented by Mike Ratcliffe [email protected] 1 Census Geographic Concepts Legal/Administrative Statistical Areas Areas Examples: Examples: •Census county divisions •States •Census designated places •Counties •Census tracts •Minor civil divisions •Metropolitan and •Incorporated places micropolitan statistical areas •Congressional districts •Urban areas •Legislative areas •Public Use Microdata Areas •School districts •Traffic Analysis Zones 2 Hierarchy of Census Geographic Entities 3 Hierarchy of American Indian, Alaska Native, and Hawaiian Entities 4 5 Hierarchy: State File Summary Levels State County County Subdivision Place (or place part) Census tract Block group Block 6 Blocks • Smallest units of data tabulation—decennial census only, but used by ACS for sample design • Cover the entire nation • Form “building blocks” for all other tabulation geographic areas • Generally bounded by visible features and legal boundaries • 4-digit block numbers completely change from census to census 7 Block Groups • Groups of blocks sharing the same first digit • Smallest areas for which sample (decennial census “long form” as well as ACS) data are available • Size: optimally 1,500 people; range between 300 to 3,000 • Proposed change in minimum threshold to 1,200 people/480 housing units 8 Census Tracts • Small, relatively permanent statistical subdivisions of a county or a statistically equivalent entity. • Increased importance over time for data analysis. • Will be used to present ACS data as well as decennial census data. • Relatively consistent boundaries over time • Size: optimally 4,000 people; range between 1,000 and 8,000 • Proposed change in minimum threshold to 1,200 people • Approximately 65,000 census tracts in U.S. • Defined nationwide for the first time in Census 2000; however Block Numbering Areas (BNAs) and tracts covered the entirety of the United States in 1990 9 Blocks, Block Groups, and Census Tracts 3006 T A s e 1007 3004 ve Lau r rel Av 3008 w e 2010 Boundaries e W Ma e t n ple M st S Ave 3007 t L 2013 t 3003 3002 S s S h Ph t y '00 Census Tract 3000 ai h r P 9 a 3007 3008 t Marylandl l 2014 6 C 2 8001.05 t 2015 Go rman A S '00 Block Group ve h 3013 3012 t 2019 2016 Way W 0 h t 1 1002 i te S 3001 3010 Arb 3011 2018 '00 Block 1 or r Wa h 2020 y C r t t D D y 1 1001 1 n n o t 2021 t la 1000 C 1 l t 1006 K Features e A Turney t n ay r S l Ave S re C u rd a t Ct 1003 th P a 1016 a l 1016 W K L 2 l St 1007 5th St 3007 e 1 a 0th Kay Street 1004 e 1015 1 r v 1008 n D 3009 3005 3006 B o 3008 A ris M t ar a H t rs n S 1009 S A ha 3001 h th 3010 rm ll C w t 1017 2005 t a 8 t l 1005 1 s 3000 S tr r 30 Marton St 1 i th on 7 3004 g Ma 3003 a C r F t 3011 sh l 2004 a Carissa 2003 ll A Ln P v Maryland G 2002 e 1011 d r 013 een 1012 8001.07 n Hill 3012 A a A rm l ve L t M s n r t Dr on ro u n 2007 Fairlawn Ave tro g o A se ve 2015 C Do A C m ve t r 2008 e 3003 Ln 2006 r D A i s v l d l e i v m l 2000 r B A b t g d 2010 S g 013 e r h a l t t l o am f 4 S e h G 2012 s B 2001 3005 A A Cherry Ln 2009 ylesford 005 Cir 2004 2011 2003 3006 d L Aylesfor n d Ln 2001 3007 2000 3008 2002 3009 2999 3010 3011 10 Exercise: Finding the census tract, block group, and block for an address • Use American Factfinder to search an address: – Select “Address Search” in lower left on AFF main page – Key in your address, click “Go” – Click “Map It” to see a map – Select one of the geographic areas listed and click “OK” to obtain data 11 12 Geographies containing 1326 Confidentiality Blvd, Cantreleaseville, Maryland, 00000 Select a geography and click “OK” 13 Exercise: Look up data using AFF • On AFF main page, select “Data Sets” then “Decennial Census” • Default is Summary File 1. Select “Detailed Tables” • Select Geographic Type: Census Tract • Select State, County, Tract from lists • Click “Add”, highlight the geographic area, then click “Next.” • On next screen, select data variable(s), add to window, click “Show Result” 14 15 Geographic Identifiers • After obtaining data for your geographic area, pull down window under “Options” tab. • Select “Show Geographic Identifiers” 16 17 Unique Geographic Identifiers To create unique identifiers for census geography: State County Place Tract** FIPS*: 47 103 25920 9754.00 Incorporated place code: 4725920 Concatenate State + Place codes, as places can cross county lines Tract code: 47103975400 Concatenate State + County + Tract codes, as tracts nest within state and county * FIPS codes can be found on the Understanding Census Geography on the Census Bureau Geography homepage: http://www.census.gov/geo/www/reference.html ** Tract codes are not designated in the FIPS codes 18 Places Incorporated Places • Legally bounded entity • Referred to as cities, boroughs, towns, or villages, depending on the state Census Designated Places (CDPs) • Statistical entity • Created to present census data for an area with a concentration of population, housing, and commercial structures that is identifiable by name, but not within an incorporated place • Example: Columbia, MD; Paradise, NV 19 Number of CDPs and Incorporated Places in the US, Puerto Rico, and the Island Areas: 2000 Incorporated CDPs Places United States 5,698 19,452 Puerto Rico 225 0 American Samoa 0 73 Guam 32 0 Northern Marianas 16 0 US Virgin Islands 6 3 20 21 Gadsden CDP, Yuma County, AZ 22 County Subdivisions Minor Civil Divisions (MCDs) • Legally bounded entity • Subcounty entities in 28 states, the District of Columbia, Puerto Rico, and the Island Areas. • May have a formal government with elected officials Census County Divisions (CCDs) • Statistical entity • Subcounty units that have stable boundaries and recognizable names in 22 states. • No minimum or maximum population guidelines 23 County Subdivisions 24 Place and County Subdivision Data in Census Bureau Tabulation Programs Tabulation Incorporated Census Minor Civil Census County Program Places Designated Divisions Divisions Places Decennial All All All All Census Population All None In 20 states only None Estimates American All, but subject All, but subject to All, but subject All, but subject Community to pop threshold pop threshold to pop threshold to pop threshold Survey requirements requirements for requirements requirements for 1-, 3-, and 1-, 3-, and 5-year for 1-, 3-, and for 1-, 3-, and 5-year averages averages 5-year averages 5-year averages Economic 5,000+ pop or 5,000+ pop or 5,000+ pop or None Census 5,000 + jobs, all 5,000 + jobs (all 5,000 + jobs (12 states but 12 strong- strong-MCD MCD states) states only) 25 Exercise: Obtaining population data for places and county subdivisions from AFF • Find the Census 2000 population, the July 1, 2005 population estimate, and the 2005 American Community Survey estimate for Columbia, Maryland • Find the same data for Framingham, Massachusetts • What differences do you find among data sets? 26 Exercise: Population Data for Places and County Subdivisions • Census 2000 populations are available for both Columbia CDP and Framingham CDP, in place tables, and Framingham town, in county subdivision tables • Because Framingham is a county subdivision in a “strong-MCD” state, population estimates are available • ACS estimates are available for Columbia CDP, Framingham CDP, and Framingham town 27 28 Census Regions and Divisions 29 Counties and County Equivalents • Counties in 48 states • Independent Cities in MD, MO, NV, and VA • Parishes in Louisiana • Cities, Boroughs, Municipality, Census Areas in Alaska • Municipios in Puerto Rico • Islands and Districts in American Samoa • Municipalities in the Northern Marianas • Islands in the Virgin Islands • District of Columbia and Guam each treated as a county equivalent 30 Urban Area Classification: Census 2000 • Urbanized Areas (UAs) of 50,000 or more people. • Urban Clusters (UCs) of 2,500 up to 50,000 people. – Both defined based on population density at the census block and block group levels. • Substantial changes to urban area concept and criteria adopted for Census 2000. www.census.gov/geo/www/ua/ua_2k.html 31 Orlando, FL Urbanized Area Boundaries '00 Urban Area '00 Place Features Water Roads 417 Orlando Urban Area 50 91 408 436 482 535 32 Core Based Statistical Area Classification Core Based Statistical Area (CBSA) – refers to both metropolitan and micropolitan statistical areas; county-based areas, defined based on commuting patterns Metropolitan Statistical Area - must have at least one UA Micropolitan Statistical Area - must have at least one UC of at least 10,000 Metropolitan Division – subdivision of a metropolitan statistical area Combined Statistical Area – represents a grouping of adjacent CBSAs. New England City and Town Area – a city- and town-based equivalent to the county-based CBSAs. Principal City – a place that occupies a more important social and economic position within a CBSA. 33 Relationship Between CSA, CBSAs, and Urban Areas: Greenville-Spartanburg-Anderson, SC 34 Creating Zip Code Tabulation Areas Determine the majority ZIP Code for each census block with addresses.