 |
        |
           |
|
|
|
|
JANUARY 2003
U.S. CENSUS BUREAU TIGER/Line 2002 Census TIGER(R) and TIGER/Line(R) are registered trademarks of the U.S. Census Bureau. ZCTA(TM) is a trademark of the U.S. Census Bureau. Windows is a registered trademark of the Microsoft Corporation. ADOBE, Acrobat, and Acrobat Reader are registered trademarks of Adobe Systems Inc. ZIP Code and ZIP+4 are trademarks of the U.S. Postal Service. Some legal boundaries and names are those reported to the U.S. Census Bureau to be legally in effect on January 1, 2000 while others are updated and legally in effect as of the latest Boundary and Annexation Survey (BAS). The boundaries represented in the 2002 TIGER/Line files are those reported to the Census Bureau by April 1, 2002 as being in effect as of January 1, 2002. The boundary information in the TIGER/Line files for both legal and statistical entities are for Census Bureau 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. WHAT ARE TIGER/LINE FILES The TIGER/Line files were created from the Census Bureau's TIGER (Topologically Integrated Geographic Encoding and Referencing) database of selected geographic and cartographic information. TIGER was developed at the Census Bureau to support the mapping and related geographic activities required by the decennial and economic censuses and sample survey programs. TIGER/Line files are made available to the public and are typically used by people to provide the digital map base for their Geographic Information System or mapping software. 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. For information on how to use the TIGER/Line data with a specific software package one should contact the company that produced the software. WHAT'S NEW - KEY CHANGES The 2002 TIGER/Line files include files for all counties and statistically equivalent entities in the United States as well as files for Puerto Rico and the Island Areas. The 2002 TIGER/Line files are released by county or statistically equivalent entity based on the current boundaries in effect as of January 1, 2002 as reported to the Census Bureau by April 1, 2002. Since Census 2000 there have been changes in the universe of counties or statistically equivalent entities. In Colorado, Broomfield County was created from parts of Adams, Boulder, Jefferson, and Weld Counties. This change has resulted in the creation of a separate TIGER/Line file for Broomfield County, Colorado. In Virginia, the independent city of Clifton Forge changed its status to become Clifton Forge town and is now part of Alleghany County, Virginia; it appears in the Alleghany County, Virginia TIGER/Line file. Beginning with the 2002 TIGER/Line files, the Census Bureau no longer will produce a TIGER/Line file for the Midway Islands. The 108th Congressional Districts do not appear in the 2002 TIGER/Line files. The Census Bureau still was in the process of collecting this information from the states at the time of the creation of the 2002 TIGER/Line files. The 2002 TIGER/Line files contain few, if any, updates to street features or address ranges from the Census 2000 versions of the TIGER/Line files. Some additional features may have been added in the 20 counties where the Census Bureau improved the street feature coordinates. In a few instances some new features may appear, and address ranges could have been added or updated, to resolve challenges as part of the Census 2000 Count Question Resolution (CQR) Program. As part of a research project to upgrade the positional accuracy of TIGER data, the Census Bureau improved the street feature coordinates in the following counties: Kent, New Castle, and Sussex Counties in Delaware; Seminole County in Florida; Cecil, Somerset and Talbot Counties in Maryland; Baltimore City in Maryland; Auglaize, Crawford, Defiance, Delaware, Fulton, Henry, Miami, Putnam, Richland, Van Wert, and Williams Counties in Ohio; and Hughes County in South Dakota. The Census Bureau has made major changes to the structure, field definitions, and contents for the 2002 TIGER/Line files. New record types have been added, two record types were deleted, and several record types were expanded and substantially revised. The Census Bureau has removed the 1990 geography from the 2002 TIGER/Line files replacing it with current geography. Also new for the 2002 TIGER/Line files is a permanent zero-cell (or node) identification number (TZID) for each node. To improve the ability of data users to merge multiple counties, the Census Bureau is adding the state and county codes to those Record Type 1 records for the adjacent county (these are the Record Type 1 records that have the single-sided segment flag set, and until this version, all the data elements for the side of the record "outside" the county have been blank). The Census Bureau also is making the TLIDs and TZIDs for these records the same. Thus the county boundary segments and zero-cells in adjacent counties will now have the same TLID and TZID. TIGER/LINE AND ACCOMPANYING FILES Each state subdirectory is named using the two-digit FIPS code and the Post Office abbreviation for the state (ex. 02_AK for Alaska). Within the state subdirectory each county file has the name TGRssccc.ZIP, where the "ss" is the state FIPS code and "ccc" is the county FIPS code. The data for each county (or statistically equivalent entity) is stored in a single compressed file that, when decompressed, results in up to 19 separate files representing each of the TIGER/Line record types that exist for that county. Some counties did not require all of the 19 record types and therefore will have less than 19 files. If the types of data contained in record types 4, 6, 7, 8, B and Z are not appropriate for a given county then the files for those record types will NOT be included. New Record Types E and U do not appear in the 2002 TIGER/Line files. The name of each of these files uses a modification of the above convention (TGRssccc.RTx) where "x" is the Record Type. Appendix A of the TIGER/line documentation provides a list of counties and their FIPS codes by state. The data in these files is in a standard ASCII format. The Census Bureau does NOT release the TIGER/Line data or an extract of the internal Census TIGER database in vendor-specific GIS/mapping software formats. KNOWN PROBLEMS AND ANOMALIES WITH THIS TIGER/LINE DATA SET: TIGER ZERO-CELL ID (TZID) Because the 2002 TIGER/Line files are the first version of the TIGER/Line files to contain the permanent zero-cell identification number (TZID), we expect there to be some possible differences between the TZIDs in the 2002 and the 2003 TIGER/Line files. The Census Bureau expects the TZIDs to be stable in the 2003 and later versions of the TIGER/Line files. The differences will mainly appear in the 20 counties listed in the What's New - Key Changes section of this document where the Census Bureau improved the street feature coordinates and possibly their adjacent counties. RANGE OF TIGER/LINE IDENTIFICATION NUMBERS (TLIDS) IN RECORD TYPE R Record Type H contains the range of unique complete chain record numbers assigned to a census file. In counties with changes to their county boundaries after January 1, 2000, the complete range of TLIDs within the current county boundary do not appear in Record Type R of the 2002 TIGER/Line file for that county. Users will need to reference Record Type R from the adjoining county to identify the potential range of unique complete chain record numbers. ADDRESS ANOMALIES IN PUERTO RICO The TIGER/Line files contain some address range coverage for Puerto Rico. However, use of this information for geocoding purposes may be problematic and the data user should proceed with caution. These address ranges are preliminary attempts at using Puerto Rico address ranges in Census Bureau files. Due to the lack of software or resources to handle some of the more unique aspects of addressing in Puerto Rico, the address ranges were entered without the standard edits and quality checks used in other parts of the United States. Improvements in software and address standardization for Puerto Rico are expected in the future. At present, there are inconsistencies, overlaps, and duplication of address ranges. Address ranges may lack alpha character prefixes or have hyphenated prefixes. The files also lack the community names used in a four-line address that the U.S. Postal Service requires to avoid duplicate addresses. Errors in the reference files, and other factors may limit the usefulness of this product for geocoding purposes. ROAD FEATURE ANOMALIES The Census Bureau extracts TIGER/Line files from the TIGER database which is continually updated. During the clerical update process for some Census 2000 operations errors caused anomalies to be introduced into some chains represented in Record Types 1 and 2. For these cases road features may appear in the 2002 TIGER/Line files unconnected to other road features (so-called floating features) or severely skewed in relation to surrounding line features of any type. We correct these errors as we find them, however, it is likely that some still exist. Another road feature anomaly is the sporadic occurrence of road segments with a misclassified Census Feature Class Code (CFCC). The result is that complete chains for the affected road features will have segments with different CFCC values assigned erroneously. This problem could affect applications that use the CFCC values for network analysis, routing, or for assigning symbology to a feature when creating a map. We believe that these errors were introduced inadvertently during an updating operation to edit address range information on new as well as existing records. We are continuing to correct these as they are discovered. QUESTIONS AND ADDITIONAL INFORMATION Questions about the Census TIGER/Line files and future plans for this and other TIGER-related products may be directed to the Geographic Products Management Branch of the Geography Division at (301) 763-1128 or to the e-mail address tiger@census.gov. General information about TIGER-related products is available from the TIGER page on the Census Bureau's World Wide Web site (http://www.census.gov/geo/www/tiger/). This Web site also is a source of other information that is of specific interest to TIGER/Line users and of general interest regarding the geographic programs at the Census Bureau. As appropriate, additional information about this product will be posted, such as ERRATA or USER NOTES. |
Sponsored by: For information regarding advertising rates Click Here! |
Copyright© 1995-2012 MindSites Group / Privacy Policy
GeoCommunity™, Wireless Developer Network™, GIS Data Depot®, and Spatial News™
including all logos and other service marks
are registered trademarks and trade communities of
MindSites Group