TIGER/Line Shapefile, 2012, state, Maryland, Current Block Group State-based

Metadata Updated: May 17, 2013

The TIGER/Line shapefiles and related database files (.dbf) are an extract of selected geographic and cartographic information from the U.S. Census Bureau's Master Address File / Topologically Integrated Geographic Encoding and Referencing (MAF/TIGER) Database (MTDB). The MTDB represents a seamless national file with no overlaps or gaps between parts, however, each TIGER/Line shapefile is designed to stand alone as an independent data set, or they can be combined to cover the entire nation. Block Groups (BGs) are defined before tabulation block delineation and numbering, but are clusters of blocks within the same census tract that have the same first digit of their 4-digit census block number from the same decennial census. For example, 2010 Census tabulation blocks 3001, 3002, 3003,.., 3999 within 2010 Census tract 1210.02 are also within BG 3 within that census tract. 2010 Census BGs generally contained between 600 and 3,000 people. Most BGs were delineated by local participants in the Census Bureau's Participant Statistical Areas Program (PSAP). The Census Bureau delineated BGs only where the PSAP participant declined to delineate BGs or where the Census Bureau could not identify any local PSAP participant. A BG usually covers a contiguous area. Each census tract contains at least one BG, and BGs are uniquely numbered within census tract. Within the standard census geographic hierarchy, BGs never cross county or census tract boundaries, but may cross the boundaries of other geographic entities like county subdivisions, places, urban areas, voting districts, congressional districts, and American Indian / Alaska Native / Native Hawaiian areas. BGs have a valid code range of 0 through 9. BGs coded 0 were intended to only include water area, no land area, and they are generally in territorial seas, coastal water, and Great Lakes water areas. For the 2010 Census, rather than extending a census tract boundary into the Great Lakes or out to the U.S. nautical three-mile limit, the Census Bureau delineated some census tract boundaries along the shoreline or just offshore. The Census Bureau assigned a default census tract number beginning with 99 and a BG number of 0 to these offshore, water-only areas not included in regularly numbered census tract areas.

Access & Use Information

Collection

This dataset is part of the following collection:

Downloads & Resources

Dates

Metadata Date June 15, 2012
Metadata Created Date March 22, 2013
Metadata Updated Date May 17, 2013
Reference Date(s) January 1, 2012 (publication)
Frequency Of Update NO CHANGES OR UPDATES WILL BE MADE TO THIS VERSION OF THE TIGER/LINE SHAPEFILES. FUTURE RELEASES OF TIGER/LINE SHAPEFILES WILL REFLECT UPDATES MADE TO THE CENSUS MAF/TIGER DATABASE.

Additional Metadata

Resource Type Dataset
Metadata Date June 15, 2012
Metadata Created Date March 22, 2013
Metadata Updated Date May 17, 2013
Reference Date(s) January 1, 2012 (publication)
Responsible Party U.S. Department of Commerce, U.S. Census Bureau, Geography Division, Geographic Products Branch (Point of Contact)
Contact Email
Access Constraints Use Constraints: The TIGER/Line Shapefile products are not copyrighted however TIGER/Line and Census TIGER are registered trademarks of the U.S. Census Bureau. These products are free to use in a product or publication, however acknowledgement must be given to the U.S. Census Bureau as the source. The boundary information in the TIGER/Line Shapefiles 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 and they are not legal land descriptions.Coordinates in the TIGER/Line shapefiles have six implied decimal places, but the positional accuracy of these coordinates is not as great as the six decimal places suggest., Access Constraints: None
Bbox East Long -74.986282
Bbox North Lat 39.723037
Bbox South Lat 37.886605
Bbox West Long -79.487651
Collection Package Id 5422b4d4-72c9-4f78-b4d8-c71bbaa002e1
Coupled Resource
Frequency Of Update NO CHANGES OR UPDATES WILL BE MADE TO THIS VERSION OF THE TIGER/LINE SHAPEFILES. FUTURE RELEASES OF TIGER/LINE SHAPEFILES WILL REFLECT UPDATES MADE TO THE CENSUS MAF/TIGER DATABASE.
Guid
Licence No warranty, expressed or implied is made with regard to the accuracy of these data, and no liability is assumed by the U.S. Government in general or the U.S. Census Bureau in specific as to the spatial 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 Shapefiles is for statistical data collection and tabulation purposes only; their depiction and designation for statistical purposes do not constitute a determination of jurisdictional authority or rights of ownership or entitlement and they are not legal land descriptions.
Metadata Language
Metadata Type geospatial
Spatial Data Service Type
Spatial Reference System
Temporal Extent Begin 2011-08-01
Temporal Extent End 2012-06-01

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