1 Proposed Urban Area Criteria for the 2010 Census Michael Ratcliffe Geography Division U.S. Census Bureau Let’s Focus on Census Geography Workshop GIS-T April 11, 2010

2 Urban and Rural Classification The Census Bureau identifies and classifies urban and rural areas after each decennial census. Urban areas of at least 2,500 people have been identified since Urbanized areas of 50,000 or more people were first defined for the 1950 Census. Urban places of at least 2,500 people were identified outside urbanized areas. Urban clusters of 2, ,999 were first defined after Census The Census Bureau identifies urban and rural areas solely for the purpose of tabulating and presenting statistical data.

3 Urban Area Definitions Represent densely developed territory, encompassing residential, commercial, and other non-residential urban land uses in which social and economic interactions occur. Represent the “Urban Footprint” Structure has been explicitly defined through measures based primarily on population counts and residential population density Criteria have also accounted for non-residential urban land uses that are functionally part of the urban landscape

4 Census 2000 Urban Areas For Census 2000, an urban area consists of a densely settled core created from census block groups, census blocks, and the adjacent densely settled surrounding territory that together have a minimum population of 2,500 people Two types of urban areas: urbanized areas of 50,000 or more population; urban clusters of 2,500 – 49,999.

5 Census 2000 Basic Urban Core Delineation

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Urban Area Program Remain committed to an objective, equitable, and consistent nationwide urban area delineation. Retain decennial comparability by building upon 2000 criteria. All potential modifications are refinements, or supplements to address deficiencies encountered for Census 2000.

Qualifying census tract ≥ 1,000 ppsm Qualifying census tract ≥ 500 ppsm contiguous to initial core Census tract not contiguous to an initial core census tract ≥ 1,000 ppsm Census tract > 3 sq. miles Initial Census Tract Core Based on Population and Size Criteria 1,600 ppsm 1,300 ppsm 750 ppsm 550 ppsm 560 ppsm 700 ppsm 800 ppsm Initial Core Using Census Tract Analysis Units

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Qualifying census tract ≥ 1,000 wpsm Qualifying census tract ≥ 500 ppsm contiguous to initial core Census tract not contiguous to an initial core census tract ≥ 1,000 wpsm Census tract > 5 sq. miles and < 15 sq. miles Initial Census Tract Core Based on Employment and Size Criteria 1,600 wpsm 1,300 wpsm 750 wpsm 550 wpsm 560 wpsm 15,000 workers And 1,200 wpsm 800 wpsm Initial Core Using Census Tract Analysis Units

Initial Core Test Delineation Regions Tract as Analysis UnitBlock Group as Analysis Unit PopulationLand Area (sq. miles) Number of Initial Urban Cores PopulationLand Area (sq. miles) Number of Initial Urban Cores 42,252,47414, ,384,95215,027904

12 Splitting Large Urban Agglomerations Census 2000 San Francisco-Oakland and San Jose Split

Commuting core A ≥ 50,000 persons Commuting core B ≥ 50,000 persons Largest worker flow to commuting core A No commuting association and largest adjacency with urban area B Largest worker flow to commuting core B Splitting Large Urban Agglomerations Using Commuting Patterns Urban area A after split Urban area B after split Urban split

14 Concord/Livermore UA Split

15 Boundary Using Proposed Impervious Criteria

Wetlands as an Additional Exempted Territory Distance from core to wetlands is 0.7 mile Distance over wetlands is 0.5 mile Distance over river is 0.6 mile Distance over wetlands is 0.7 mile Distance from wetlands to noncontiguous qualifying area is 0.7 mile Total jump distance is 3.2 miles Urban Core Noncontiguous qualifying territory Jump census block Road connection Total exempted distance is 1.8 miles

17 Steep Slope as Exempted Territory

Qualification of Airports for Inclusion in Urban Areas Merced Municipal/MacCready Field, Merced CA

19 Prison Urban Clusters Abilene North (Robertson Unit), TX Population: 4,650 Urban: 4,650 Group Quarters: 4,650 Institutional: 4,650 Correctional: 4,650 Density: 94,589 ppsm

20 Central Places Central places are not necessary for UA or UC delineation Principal cities defined within CBSAs: capture same concept classification based on different criteria Lack of consideration of place boundaries in delineation process results in central places split between urban and rural portions.

21 Questions? Comments? Vincent Osier Chief Geographic Standards and Criteria Branch Geography Division U.S. Census Bureau (301) Chris Henrie Geographic Standards and Criteria Branch Geography Division U.S. Census Bureau (301)