Census_Blocks

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.

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.

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

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 Redistricting 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 favorable 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.

Date the file was made available to create TIGER/Line File extracts.

To obtain more information about ordering TIGER/Line files visit
http://www.census.gov/geo/www/tiger.
Technical_Prequisites: The Redistricting Census 2000 TIGER/Line files contain geographic
data only and do not include display or mapping software or statistical data.  A
list of vendors who have developed software capable of processing TIGER/Line files
can be found by visiting http://www.census.gov/geo/www/tiger