TIGER/Line(TM) Files, 1992 Introduction TIGER/Line(TM) Files, 1992 Developed by the Bureau of the Census Washington: The Bureau [producer and distributor],1993. Type of File and Geographic Extent The TIGER/Line(TM) Files, 1992 (1992 TIGER/Line files) (version 5) are extracts of selected geographic and cartographic information from the Census Bureau's TIGER (Topologically Integrated Geographic Encoding and Referencing) System. The 1992 TIGER/Line files reflect the dramatic increase in the number of new address ranges based on 1990 census address lists and contain geographic code changes. These files have a similar format and structure as the TIGER/Line(TM) Census Files, 1990 (1990 Census TIGER/Line files) but include two new record types that accommodate additions, corrections, and updates to the inventory of geographic entities made since the 1990 census. The 1992 TIGER/Line files are being released by county or statistically equivalent entity based on the 1990 census tabulation and publication boundaries. There will be 3,248 files covering the 50 States and seven statistically equivalent entities. This version will exclude the Federated States of Micronesia and the Marshall and Midway Islands. Principal Differences Between the 1990 Census TIGER/Line Files and the 1992 TIGER/Line Files New Record Types Added The 1992 TIGER/Line files include two new record types -- Record Types F and G. Record Type F shows geographic codes as of January 1, 1990 that have been corrected to resolve questions local officials raised about the 1990 census data tabulations. Record Type G shows geographic codes (generally as of January 1, 1992) in those situations for which geographic entities reported changes in their boundaries during the Census Bureau's annual survey of governmental units. These record types are present only when they contain information different from the codes shown in Record Type 1 or Record Type A (the January 1, 1990 geographic entities and codes by which the 1990 census was tabulated and its data products published). Record Types F and G are independent of each other. Record Type F shows the corrections to the 1990 census geographic codes as differences from Record Type A, while Record Type G shows the January 1, 1992 updates as differences from Record Type A (including those changes that appear in Record Type F unless replaced by subsequent changes). Chapter 6 lists the content and the layouts for these new record types. Boundary and Area Changes Since the release of the 1990 Census TIGER/Line files, the Census Bureau has shifted and reshaped some line features including boundary lines. These changes involve the realignment of features associated with corporate boundary corrections and changes. The shape and area of the geographic entities depicted in the 1992 TIGER/Line files may differ from the earlier version despite the fact that they represent the entity as it existed on January 1, 1990. However, the inventory of 1990 census tabulation entities remains the same. Previously Blank Fields Filled Within Record Type A, the following fields now have data; they were blank previously. Field Description SDELM Elementary School District Code SDMID Middle School District Code SDSEC Secondary School District Code SDUNI Unified School District Code UA 1990 Census Urbanized Area Code URBFLAG 1990 Urban/Rural Indicator (U/R) CD103 103rd Congressional District Code New Address Ranges and ZIP Codes(R) In almost all counties or county equivalents, the Census Bureau has added additional potential address ranges and ZIP Codes(R) based on the 1990 census Address Control File (ACF). The 1992 TIGER/Line files include the new address ranges only for street segments that contained no address range information in earlier versions of the TIGER/Line(TM) files. The Census Bureau is not revising or expanding pre-existing address ranges (primarily in metropolitan areas) to reflect the assignment of specific address in the ACF in the 1992 TIGER/Line files. The new address ranges and ZIP Codes have not been edited for overlaps or other inconsistencies. The imputed address flags on Record Types 1 and 6 have additional values that identify those address ranges based on the ACF. Figure I-1 is a map showing the residential address range coverage in the 1990 Census TIGER/Line files, by county/statistical equivalent in the United States1 . On this map, address range coverage is based on the total number of street segments with address ranges relative to the total number of street segments in the county/statistical equivalent. Figure I-2 is a map showing the proportion of city style addresses included in the address ranges in the Census TIGER data base for each county/statistical equivalent relative to the total number of residential addresses in the county/statistical equivalent. Addresses included in the 1990 census that are not covered by an address range in the Census TIGER data base either were rural addresses, Post Office (PO) box addresses, or city style addresses that the Census Bureau could not match to a feature in the TIGER data base. Appendix A lists the address range coverage category for each county and statistically equivalent entity. Even though the maps in Figures 1 and 2 measure address range coverage in different ways, they do show counties for which full to limited address range coverage is available in the 1992 TIGER/Line files that did not have as much (or any) address range coverage in earlier versions. File Availability The 1992 TIGER/Line files are available on CD-ROM, magnetic tape, or tape cartridge (IBM 3480 compatible) from Customer Services Branch, Data User Services Division, Washington, DC 20233-8300; (301) 763-4100. FAX: (301) 763-4794. For pricing information, contact Customer Services Branch, Data User Services Division. How to Use This Documentation The structure of this document is based on data content rather than record type content. For instance, all references to addresses appear in one section, with references to other sections that contain relevant information. In order to make the document easier to use as a reference, the text contains some repetition from section to section. Chapter 1 describes the basic concepts about TIGER and the TIGER/Line(TM) product. It discusses the topology in the Census TIGER data base, the terminology used in this document to describe the geographic data, and provides an overview of the record types that make up the TIGER/Line(TM) files. The documentation for the 1992 TIGER/Line files utilizes the Federal Information Processing Standards (FIPS) Spatial Data Transfer Standard (SDTS) nomenclature for geographic objects. Anyone new to the TIGER/Line(TM) files or unfamiliar with these terms should review this chapter. Chapter 2 discusses the principle identification numbers that form the basis for record linkage discussed throughout the documentation. Chapter 3 discusses the attributes for the line, polygon, and landmark geographic data types. Chapter 4 defines the types of geographic entities and entity codes that appear in the TIGER/Line(TM) file. Because the geographic entity codes are associated with both lines and polygons, the documentation discusses them in this separate chapter. This chapter also identifies some of the fundamental relationships among the different types of geographic entities. Chapter 5 summarizes the data quality aspects of the information in the TIGER data base using the SDTS quality modules. Chapter 6 lists the contents of the 1992 TIGER/Line files record types and provides a detailed description of the data fields in each. The intent is that one will use Chapter 6 in conjunction with Chapters 3 and 4 to locate the positions of specific data fields in the 1992 TIGER/Line files. ____________________________ TIGER/Line(TM), TIGER/SDTS(TM), and TIGER/UA Limit Files(TM) are trademarks of the U.S. Bureau of the Census. ZIP Code(R) is a registered trademark of the U.S. Postal Service. 1 The county boundary file for Figures I-1 and I-2 comes in part from Environmental Systems Research Institute, Inc.