SDETrims.DBO.Bound_CensusBlocks

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Frequently-anticipated questions:

What does this data set describe?

Title: SDETrims.DBO.Bound_CensusBlocks
Abstract:
TIGER, TIGER/Line, and Census TIGER are registered trademarks of the U.S. Census Bureau. ZCTA is a trademark of the U.S. Census Bureau. The Census 2000 TIGER/Line files are an extract of selected geographic and cartographic information from the Census TIGER data base. The TIGER/Line data are not in a mapping projection even though most of the features were scanned directly from source maps that were in a projection. The North American Datum of 1983 (NAD83) is the coordinate datum used for the 48 contiguous states, the District of Columbia, Alaska, Puerto Rico, and the Virgin Islands of the United States. Regional datums are used for Hawaii and the Pacific Island Areas. The geographic coverage for a single TIGER/Line file is a county or statistical equivalent entity, with the coverage area based on January 1, 2000 legal boundaries. A complete set of Census 2000 TIGER/Line files includes all counties and statistically equivalent entities in the United States, Puerto Rico, and the Island Areas. The Census 2000 TIGER/Line files do not include a file for Broomfield County, Colorado which became effective November 15, 2001. The Census TIGER data base represents a seamless national file with no overlaps or gaps between parts. However, each county-based TIGER/Line file is designed to stand alone as an independent data set or the files can be combined to cover the whole Nation. The Census 2000 TIGER/Line files consist of line segments representing physical features and governmental and statistical boundaries. The boundary information in the TIGER/Line files are for statistical data collection and tabulation purposes only; their depiction and designation for statistical purposes does not constitute a determination of jurisdictional authority or rights of ownership or entitlement. The Census 2000 TIGER/Line files do NOT contain the Census 2000 urban areas which have not yet been delineated. The files contain information distributed over a series of record types for the spatial objects of a county. There are 17 record types, including the basic data record, the shape coordinate points, and geographic codes that can be used with appropriate software to prepare maps. Other geographic information contained in the files includes attributes such as feature identifiers/census feature class codes (CFCC) used to differentiate feature types, address ranges and ZIP Codes, codes for legal and statistical entities, latitude/longitude coordinates of linear and point features, landmark point features, area landmarks, key geographic features, and area boundaries. The Census 2000 TIGER/Line data dictionary contains a complete list of all the fields in the 17 record types.
Supplemental_Information:
To find out more about TIGER/Line files and other Census TIGER data base derived data sets visit <http://www.census.gov/geo/www/tiger>.
  1. How should this data set be cited?

    U.S. Department of Commerce U.S. Census Bureau Geography Division, 2001, SDETrims.DBO.Bound_CensusBlocks: TIGER/Line Files Each file contains a version code that uniquely identifies each specific release of a version of the TIGER/Line files. The version code (MMYY) represents the month and year that the data in the file was extracted from the TIGER database., U.S. Department of Commerce U.S. Census Bureau Geography Division, Washington, DC.

    Online Links:

    • Service=sde:sqlserver:CHUCKNORRIS; Database=SDETrims; Version=dbo.DEFAULT

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -98.954094
    East_Bounding_Coordinate: -94.070955
    North_Bounding_Coordinate: 34.157109
    South_Bounding_Coordinate: 29.496422

  3. What does it look like?

  4. Does the data set describe conditions during a particular time period?

    Calendar_Date: 2000
    Currentness_Reference: 2000

  5. What is the general form of this data set?

    Geospatial_Data_Presentation_Form: vector digital data

  6. How does the data set represent geographic features?

    1. How are geographic features stored in the data set?

      Indirect_Spatial_Reference:
      Federal Information Processing Standards (FIPS) and feature names and addresses.
      This is a Vector data set. It contains the following vector data types (SDTS terminology):
      • G-polygon (143728)
      • Entity point
      • Complete chain (15 to 303,000)
      • GT-polygon composed of chains (5 to 100,200)

    2. What coordinate system is used to represent geographic features?

      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.000000. Longitudes are given to the nearest 0.000000. Latitude and longitude values are specified in Decimal degrees.

      The horizontal datum used is North American Datum of 1983.
      The ellipsoid used is Geodetic Reference System 80.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257222.

      Vertical_Coordinate_System_Definition:
      Altitude_System_Definition:
      Altitude_Resolution: 1.000000
      Altitude_Encoding_Method:
      Explicit elevation coordinate included with horizontal coordinates

  7. How does the data set describe geographic features?

    SDETrims.DBO.Bound_CensusBlocks

    OBJECTID
    Internal feature number. (Source: ESRI)

    Sequential unique whole numbers that are automatically generated.

    ID

    STFID

    STATE

    COUNTY

    TRACT

    BLOCK

    POP2000

    WHITE

    BLACK

    AMERI_ES

    ASIAN

    HAWN_PI

    OTHER

    MULT_RACE

    HISPANIC

    MALES

    FEMALES

    AGE_UNDER5

    AGE_5_17

    AGE_18_21

    AGE_22_29

    AGE_30_39

    AGE_40_49

    AGE_50_64

    AGE_65_UP

    MED_AGE

    MED_AGE_M

    MED_AGE_F

    HOUSEHOLDS

    AVE_HH_SZ

    HSEHLD_1_M

    HSEHLD_1_F

    MARHH_CHD

    MARHH_NO_C

    MHH_CHILD

    FHH_CHILD

    FAMILIES

    AVE_FAM_SZ

    HSE_UNITS

    URBAN

    RURAL

    VACANT

    OWNER_OCC

    RENTER_OCC

    Shape
    Feature geometry. (Source: ESRI)

    Coordinates defining the features.

    Shape.area

    Shape.len

    Entity_and_Attribute_Overview:
    The TIGER/Line files contain data describing three major types of features/entities; Line Features - 1) Roads 2) Railroads 3) Hydrography 4) Miscellaneous transportation features and selected power lines and pipe lines 5) Legal (governmental unit) and statistical boundaries Landmark Features - 1) Point landmarks, e.g., schools and churches. 2) Area landmarks, e.g., Parks and cemeteries. 3) Key geographic locations (KGLs), e.g., shopping centers and factories. Polygon features - 1) Geographic entity codes for areas used to tabulate the Census 2000 census statistical data and 1990 geographic areas 2) Locations of area landmarks 3) Locations of KGLs The line features and polygon information form the majority of data in the TIGER/Line files. Some of the data/attributes describing the lines include coordinates, feature identifiers (names), CFCCs (used to identify the most noticeable characteristic of a feature), address ranges, and geographic entity codes. The Census Bureau includes landmark features on an as-needed-basis and has made no attempt to ensure that all instances of a particular landmark feature were included. The TIGER/Line files contain point and area labels that describe landmark features and provide locational reference. Area landmarks consist of a feature name or label and feature type assigned to a polygon or group of polygons. Landmarks may overlap or refer to the same set of polygons. The Census TIGER data base uses collections of spatial objects (points, lines, and polygons) to model or describe real-world geography. The Census Bureau uses these spatial objects to represent features such as streets, rivers, and legal boundaries and assigns attributes to these features to identify and describe specific features such as the 500 block of Market Street in Philadelphia, Pennsylvania.
    Entity_and_Attribute_Detail_Citation:
    U.S. Census Bureau, TIGER/Line files, Census 2000 Technical Documentation. The TIGER/Line documentation defines the terms and definitions used within the files.

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)

  2. Who also contributed to the data set?

  3. To whom should users address questions about the data?

Why was the data set created?

In order for others to use the information in the Census TIGER data base in a geographic information system (GIS) or for other geographic applications, the Census Bureau releases to the public extracts of the data base in the form of TIGER/Line files. Various versions of the TIGER/Line files have been released; previous versions include the 1990 Census TIGER/Line files, the 1992 TIGER/Line files, the 1994 TIGER/Line files, the 1995 TIGER/Line files, the 1997 TIGER/Line files, the 1998 TIGER/Line files, the 1999 TIGER/Line files, and the Redistricting Census 2000 TIGER/Line files.

How was the data set created?

  1. From what previous works were the data drawn?

    TIGER (source 1 of 1)
    U.S. Department of Commerce U.S. Census Bureau Geography Division, Unpublished material, Census TIGER data base.

    Type_of_Source_Media: On line
    Source_Contribution:
    Selected geographic and cartographic information (line segments) from the Census TIGER data base.

  2. How were the data generated, processed, and modified?

    Date: 2000 (process 1 of 2)
    In order for others to use the information in the Census TIGER data base in a GIS or for other geographic applications, the Census Bureau releases periodic extracts of selected information from the Census TIGER data base, organized as topologically consistent networks. Software (TIGER DB routines) written by the Geography Division allows for efficient access to Census TIGER system data. TIGER/Line files are extracted from the Census TIGER data base by county or statistical equivalent area. Census TIGER data for a given county or statistical equivalent area is then distributed among 17 fixed length record ASCII files, each one containing attributes for either line, polygon, or landmark geographic data types. The Census Bureau has released various versions of the TIGER/Line files since 1988, with each version having more updates (feature and feature names, address ranges and ZIP Codes, coordinate updates, revised field definitions, etc.) than the previous version.

    Data sources used in this process:

    • Census TIGER data base

    (process 2 of 2)
    Metadata imported.

    Data sources used in this process:

    • C:\DOCUME~1\adube\LOCALS~1\Temp\xmlB9.tmp

  3. What similar or related data should the user be aware of?

How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?

    Accurate against Federal information Processing Standards (FIPS), FIPS Publication 6-4, and FIPS-55 at the 100% level for the codes and base names. The remaining attribute information has been examined but has not been fully tested for accuracy.

  2. How accurate are the geographic locations?

    The information present in these files is provided for the purposes of statistical analysis and census operations only. Coordinates in the TIGER/Line files have six implied decimal places, but the positional accuracy of these coordinates is not as great as the six decimal places suggest. The positional accuracy varies with the source materials used, but generally the information is no better than the established national map Accuracy standards for 1:100,000-scale maps from the U.S. Geological Survey (USGS); thus it is NOT suitable for high-precision measurement applications such as engineering problems, property transfers, or other uses that might require highly accurate measurements of the earth's surface. The USGS 1:100,000-scale maps met national map accuracy standards and use coordinates defined by the North American Datum, 1983. For the contiguous 48 States, the cartographic fidelity of most of the Census 2000 TIGER/Line files, in areas outside the 1980 census Geographic Base File/Dual Independent map Encoding (GBF/DIME) file coverage and selected other large metropolitan areas, compare favorably with the USGS 1:100,000-scale maps. The Census Bureau cannot specify the accuracy of features inside of what was the 1980 GBF/DIME-File coverage or selected metropolitan areas. The Census Bureau added updates to the TIGER/Line files that enumerators annotated on maps sheets prepared from the Census TIGER data base as they attempted to traverse every street feature shown on the Census 2000 map sheets; the Census Bureau also made other corrections from updated map sheets supplied by local participants for Census Bureau programs. The locational accuracy of these updates is of unknown quality. In addition to the Federal, State, and local sources, portions of the files may contain information obtained in part from maps and other materials prepared by private companies. Despite the fact the TIGER/Line data positional accuracy is not as high as the coordinate values imply, the six- decimal place precision is useful when producing maps. The precision allows features that are next to each other on the ground to be placed in the correct position, on the map, relative to each other, without overlap.

  3. How accurate are the heights or depths?

  4. Where are the gaps in the data? What is missing?

    Data completeness of the TIGER/Line files reflects the contents of the Census TIGER data base at the time the TIGER/Line files (Census 2000 version) were created.

  5. How consistent are the relationships among the observations, including topology?

    The feature network of lines (as represented by Record Types 1 and 2) is compete for census purposes. Spatial objects in TIGER/Line belong to the "Geometry and Topology" (GT) class of objects in the "Spatial Data Transfer Standard" (SDTS) FIPS Publication 173 and are topologically valid. Node/geometry and topology (GT)-polygon/chain relationships are collected or generated to satisfy topological edit requirements. These requirements include: * Complete chains must begin and end at nodes. * Complete chains must connect to each other at nodes. * Complete chains do not extend through nodes. * Left and right GT-polygons are defined for each complete chain element and are consistent throughout the extract process. * The chains representing the limits of the files are free of gaps. The Census Bureau performed automated tests to ensure logical consistency and limits of files. All polygons are tested for closure. The Census Bureau uses its internally developed Geographic Update System to enhance and modify spatial and attribute data in the Census TIGER data base. Standard geographic codes, such as FIPS codes for states, counties, municipalities, and places, are used when encoding spatial entities. The Census Bureau performed spatial data tests for logical consistency of the codes during the compilation of the original Census TIGER data base files. Most of the Codes themselves were provided to the Census Bureau by the USGS, the agency responsible for maintaining FIPS 55. Feature attribute information has been examined but has not been fully tested for consistency.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?

Access_Constraints: None
Use_Constraints:
None. Acknowledgment of the U.S. Census Bureau would be appreciated for products derived from these files. TIGER, TIGER/Line, and Census TIGER are registered trademarks of the U.S. Census Bureau. ZCTA is a trademark of the U.S. Census Bureau.

  1. Who distributes the data set? (Distributor 1 of 1)

    U.S. Department of Commerce
    8903 Presidential Parkway, Room 520 WP I
    Upper Marlboro, Maryland 20772

    (301) 763-1128 (voice)
    (301) 457-4710 (FAX)

  2. What's the catalog number I need to order this data set?

    Census 2000 TIGER/Line Files

  3. What legal disclaimers am I supposed to read?

    No warranty, expressed or implied is made and no liability is assumed by the U.S. Government in general or the U.S. Census Bureau in specific as to the positional or attribute accuracy of the data. The act of distribution shall not constitute any such warranty and no responsibility is assumed by the U.S. Government in the use of these files. The boundary information in the TIGER/Line files are for statistical data collection and tabulation purposes only; their depiction and designation for statistical purposes does not constitute a determination of jurisditional authority or rights of ownership or entitlement.

  4. How can I download or order the data?

  5. What hardware or software do I need in order to use the data set?

    The Census 2000 TIGER/Line files contain geographic data only and do not include display or mapping software or statistical data. For information on how to use the TIGER/Line data with a specific software package users should contact the company that produced the software. A list of some vendors who have developed software capable of processing TIGER/Line files can be found by visiting <http://www.census.gov/geo/www/tiger>. The TIGER/Line files are provided in ASCII text format only. Users are responsible for converting or translating the files into a format used by their specific software package.

Who wrote the metadata?

Dates:
Last modified: 20-Aug-2007
Metadata author:
U.S. Department of Commerce
c/o REQUIRED: The person responsible for the metadata information.
8903 Presidential Parkway, Room 520 WP I
Upper Marlboro, Maryland 20772

(301) 763-1128 (voice)
tiger@census.gov

Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)
Metadata extensions used:

Generated by mp version 2.8.6 on Mon Aug 20 13:52:38 2007