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Census Databases

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blue ballInterested in Metadata about LandView Census 2000 components?

The following Census Bureau data are presented in LandView® 6:

  1. Census 2000 demographic data.
  2. Historical population and housing unit counts for states and counties.
  3. MARPLOT® Census demographic layer grouping- represents the generalized and detailed boundary files used to display Census 2000 statistical and legal entities.
  4. MARPLOT Census 2000 TIGER/Line® layers grouping- Census 2000 TIGER/Line data used to display roads, railroads, shoreline, water and other features.

Census 2000 Population and Housing Data

The Census 2000 data in LandView 6 are based on the data tables presented in the Census 2000 Demographic Profiles. Statistical table DP-1 contains selected data items plus calculated statistics derived from the 1,040 statistical tables contained in Census 2000 Summary File 1 file (SF 1). Statistical tables DP-2 through DP-4 contains selected data items plus calculated statistics derived from the 813 statistical tables contained in Census 2000 Summary File 3 file (SF 3).

Data are presented for the 50 states, the District of Columbia and Puerto Rico. The data presentation for all geographic levels except census blocks are based on the Census 2000 Demographic Profiles. About the Profile [PDF] provides an explanation of the data table content and derived measures.

The LandView product provides demographic profiles (excepting census blocks) for additional geographic levels not presented in the Census 2000 Demographic Profile product (i.e. census tracts, census block groups and ZCTAs). The census block statistics were created from selected data items contained in the Census 2000 Summary File 1 (SF1).

The SF1 files include statistical data on the following population and housing items based on a limited set of questions asked of every person and housing unit in the United States. These items are: age, race, sex, Hispanic or Latino origin, household relationship, and household and family characteristics. Housing items include occupancy status and tenure (whether the unit is owner- or renter-occupied).

Summary File 3 (SF 3) contains the sample data, which is the information compiled from the questions asked of a sample of all people and housing units. Population items include basic population totals; urban and rural; households and families; marital status; grandparents as caregivers; language and ability to speak English; ancestry; place of birth, citizenship status, and year of entry; migration; place of work; journey to work (commuting); school enrollment and educational attainment; veteran status; disability; employment status; industry, occupation, and class of worker; income; and poverty status. Housing items include basic housing totals; urban and rural; number of rooms; number of bedrooms; year moved into unit; household size and occupants per room; units in structure; year structure built; heating fuel; telephone service; plumbing and kitchen facilities; vehicles available; value of home; monthly rent; and shelter costs.

For more information about these files go to Your Gateway to Census 2000.

Historical Population and Housing Unit Counts for States and Counties

The 1970, 1980, 1990 population and housing unit counts were derived from the Census USA Counties 1998 CD-ROM. These data are available only for the 50 states and the District of Columbia. Please refer to the Guide to the USA Counties CD-ROM [PDF] for more technical information regarding the quality and source of these data.

Please note that the 1970-1990 population figures are revised. The 1970-1980 housing units are revised; the 1990 housing unit counts are not. The following briefly explains how the population figures are revised. The April 1 census population is a count of the number of persons residing in an area (resident population) as reported in the census of population, or as subsequently revised through the annual population estimates . Revisions to an area's census population count may occur as the result of (1) post-census corrections of political boundaries, geographic misallocations, or documented under enumerations or over enumerations, and (2) geographic boundary updates made after the census, resulting from annexations, deannexations, new incorporations, governmental mergers, and so forth. The closing date to include these two forms of revisions for 1990 in this set of estimates was December 1996.

The counties and equivalent areas shown are defined as of January 1, 1992. Because the county boundaries and Census 2000 data shown in LandView 5 are defined as of January 1, 2000, counties that were defined after January 1, 1992 will not have historical data. Consequently, historical data will not be shown for the Skagway-Hoonah-Angoon Census Area (02232) and Yakutat City and Borough (02282). A supplemental source of information on county boundary changes can be found at the Changes to Counties and County Equivalent Entities: 1970-Present Web site.

We are presenting these data to give LandView users a sense of population growth for these areas. However, some dramatic population changes in states such as Alaska and Virginia may be attributed to geographic boundary updates between censuses involving annexations, deannexations, new incorporations,governmental mergers and so forth. Users should refer to the footnotes in the USA Counties 1998 CD-ROM for further details.

Additional historical census information may be obtained from the Population of Counties by Decennial Census: 1900 to 1990 Web site or the Population Division Web site.

MARPLOT® Census Demographic Layer Grouping

This layer grouping displays the following legal and statistical entities:

  1. urbanized areas/urban clusters,
  2. states,
  3. state portions of Indian Areas,
  4. state portions of ZIP Code Tabulation Areas (ZCTAs),
  5. 106th and 108th Congressional Districts,
  6. places,
  7. consolidated cities,
  8. counties,
  9. minor civil divisions (MCDs in 20 states only),
  10. census tracts, census block groups, and selected census block points.

Special Note Regarding Urbanized Areas and Urban Clusters

The MARPLOT "Urban Areas" layers shows detailed boundaries of urbanized areas and urban clusters as defined in the Federal Register / Vol. 67, No. 84 / Wednesday, May 1, 2002 / Notice. The May 1 boundaries will agree with the Census 2000 SF3 urban/rural tabulations and do not reflect subsequent corrections to the May 1, 2002 Notice.

For further information regarding the corrections and to obtain corrected boundary files see the Census 2000 Urban and Rural Classification site.

Special Note Regarding Minor Civil Divisions

The U.S. Census Bureau recognizes MCDs in 28 states. LandView, however, provides data for 20 states and Puerto Rico. The states are: Connecticut, Illinois, Indiana, Iowa, Kansas, Maine, Massachusetts, Michigan, Minnesota, Nebraska, New Hampshire, New Jersey, New York, North Dakota, Ohio, Pennsylvania, Rhode Island, South Dakota, Vermont, and Wisconsin.

Special Note Regarding Census Block Points

To conserve disc space and speed the display of the census block points layer, census block points containing zero population and zero housing units are excluded from the census blocks database and the associated map layer. Consequently, only two thirds of the census block points (i.e. 5,471,376 out of 8,262,363) are shown.

Understanding Generalized and Detailed Boundaries

Both generalized and detailed boundary files were used to create the individual layers presented in the Census Demographic Layer grouping of MARPLOT®.

The boundary files used in the Indian Areas, (American Indian/Hawaiian Home Land), Urban Areas, Congressional Districts (106th and 108th), places, consolidated cities, census tracts, census block groups, and ZIP Code® Tabulation Areas (ZCTAs) layers were neither generalized nor clipped to the shoreline. Consequently, they provide the greatest coordinate resolution describing shapes with the same resolution as the TIGER file and do extend into large bodies of water.

The boundary files used in the state, county, and minor civil divisions layers are generalized which means that the number of lines making up the perimeter of those polygons are reduced, and the polygon shapes are simplified. Generalized files were used for these geographic layers because these files were clipped against the same generalized representation of the United States coastline, and they retain coincidence for boundaries shared between these layers (e.g. counties nest within state). Another benefit of the generalization process is that it reduces the size of the map files and speeds their display.

In comparing two layers sharing a common boundary where one is generalized and the other is detailed, there will be discrepancies. The layer that is not generalized depicts the actual boundary as stored in the TIGER/Line files. For example, the census tract boundaries are not generalized and they nest within county. Consequently, they depict the actual county boundaries in those situations where the census tract boundary coincides with the county boundary.

The generalized files are available along with further technical details and metadata from the Geography Division Cartographic Boundary File site. The detailed files are not available to the public. Since these files are derived from Census 2000 TIGER/Line, see the discussion below regarding Census 2000 TIGER/Line technical characteristics.

Consolidated Cities and Places

We present maps and data for consolidated cities and places in separate layers.

For Census 2000, there are seven consolidated cities:

A consolidated city is a consolidated government for which the functions of an incorporated place and its county or minor civil division (MCD) have merged. The legal aspects of this action may result in both the primary incorporated place and the county or MCD continuing to exist as legal entities, even though the county or MCD performs few or no governmental functions and has few or no elected officials. Where this occurs, and where one or more other incorporated places in the county or MCD continue to function as separate governments, even though they have been included in the consolidated government, the primary incorporated place is referred to as an consolidated city.

The data for the consolidated city includes the data for all places that are part of and within the consolidated city. The "consolidated city (balance)" entries are shown in the places layer and show data for the portion of the consolidated government minus the separately incorporated places within the consolidated city. Note that for data presentation purposes these "balance" entities are treated as statistically equivalent to a place; they have no legal basis or function.

For further information regarding Census 2000 geographic terms and concepts please see Appendix A. Census 2000 Geographic Terms and Concepts [PDF]. The relationship between various legal and statistical entities is shown in the LandView 6 Geographic Hierarchy diagram.

MARPLOT Census 2000 TIGER/Line® Layers Grouping

The Census 2000 TIGER/Line files were processed to create the individual layers (i.e. roads, railroads, shoreline, water and other features) as shown in the Census 2000 TIGER/Line group layer of MARPLOT. The TIGER/Line files are digital databases of geographic features, such as roads, railroads, rivers, lakes, political boundaries, census statistical boundaries, etc. covering the entire United States. The data base contains information about these features such as their location in latitude and longitude, the name, the type of feature, address ranges for most streets, the geographic relationship to other features, and other related information. They are the public product created from the Census Bureau's TIGER (Topologically Integrated Geographic Encoding and Referencing) database of geographic information. The TIGER data base was developed at the Census Bureau to support the mapping and related geographic activities required by the decennial census and sample survey programs. For further details see the Census 2000 TIGER/Line technical documentation [PDF].

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