10,000+ results returned
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Title: New York City ZIP Code Tabulation Areas (ZCTA5), 2008
Contributors:- Polygon data
- 2008
Summary: New York City ZIP Code Tabulation Areas (ZCTA5) is a polygon theme representing zip code areas in New York City.
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Title: New York City Elementary School Districts, 2008
Contributors:- Polygon data
- 2008
Summary: New York City Elementary School Districts, 2008 is a polygon theme representing elementary school districts in New York City in 2008.
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Title: U.S. Census Urban Areas, 2013
Contributors:- Polygon data
- 2013
Summary: U.S. Census Urban Areas represents the 2010 Census urban areas in the United States. An urban area comprises a densely settled core of census tracts and/or census blocks that meet minimum population density requirements, along with adjacent territory containing non-residential urban land uses as well as territory with low population density included to link outlying densely settled territory with the densely settled core. To qualify as an urban area, the territory identified according to criteria must encompass at least 2,500 people, at least 1,500 of which reside outside institutional group quarters. The U.S. Census Bureau identifies two types of urban areas—Urbanized Areas (UA) of 50,000 or more people and Urban Clusters (UC) of at least 2,500 and less than 50,000 people. The U.S. Census Bureau delineates urban areas that represent densely developed territory, encompassing residential, commercial, and other non-residential urban land uses. In general, this territory consists of areas of high population density and urban land use resulting in a representation of the "urban footprint."
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Title: U.S. Census Urbanized Areas, 2013
Contributors:- Polygon data
- 2010
Summary: U.S. Census Urbanized Areas represents the 2010 Census urban areas in the United States. An urban area comprises a densely settled core of census tracts and/or census blocks that meet minimum population density requirements, along with adjacent territory containing non-residential urban land uses as well as territory with low population density included to link outlying densely settled territory with the densely settled core. To qualify as an urban area, the territory identified according to criteria must encompass at least 2,500 people, at least 1,500 of which reside outside institutional group quarters. The U.S. Census Bureau identifies two types of urban areas—Urbanized Areas (UA) of 50,000 or more people and Urban Clusters (UC) of at least 2,500 and less than 50,000 people. The U.S. Census Bureau delineates urban areas that represent densely developed territory, encompassing residential, commercial, and other non-residential urban land uses. In general, this territory consists of areas of high population density and urban land use resulting in a representation of the "urban footprint."
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Title: Census Blocks, 2000 - San Francisco Bay Area, California
Contributors:- Polygon data
- 2002
- California. Metropolitan Transportation Commission
- U.S. Department of Commerce, Bureau of the Census, Geography Division
Summary: The polygons in this data layer represent U.S. Census Blocks for the San Francisco Bay Area in California. These data have been clipped to the shoreline for cartographic representation. Census blocks are statistical areas bounded on all sides by visible features such as streets, roads, streams, and railroad tracks, and by invisible boundaries such as city, town, township, and county limits, and short imaginary extensions of streets and roads. Generally census blocks are small in area; for example, a block in a city bounded by streets. However, census blocks in remote areas may be large and irregular and contain hundreds of square miles. All territory in the United States, Puerto Rico, and the Island Areas have block numbers. Blocks are composed of one or more GT-polygons; that is, several GT-polygons can share the same block number. Census 2000 Block Numbers. Census 2000 tabulation blocks are numbered uniquely within each state/county/census tract with a four-digit census block number. The U.S. Census Bureau created the tabulation block numbers immediately before beginning its Census 2000 data tabulation process, thereby eliminating block suffixes. The first digit of the tabulation block number identifies the block group. For the 1990 census, the U.S. Census Bureau assigned a unique 1990 block number with a suffix of "Z" to identify crews-of-vessels population. For Census 2000, crews-of-vessels population is assigned to the land block identified by the U.S. Census Bureau as associated with the home port of the vessel. Water Blocks. The U.S. Census Bureau introduced a different method for identifying the water areas of census blocks for Census 2000. For the 1990 census, water was not uniquely identified within a census block; instead, all water area internal to a block group was given a single block number ending in "99" (for example, in block group 1, all water was identified as block 199). A suffix was added to each 1990 water block number where the block existed in more than one tabulation entity within its block group. For Census 2000, water area located completely within the boundary of a single land block has the same block number as that land block. Water area that touches more than one land block is assigned a unique block number not associated with any adjacent land block. The U.S. Census Bureau assigned water block numbers beginning with the block group number followed by "999 " and preceding in descending order. For example, in block group 3, the block numbers assigned to water areas that border multiple land blocks are 3999, 3998, 3997, and so forth. Because some land blocks include water (ponds and small lakes), no conclusions about whether or not a block is all land or all water can be made by looking at the Census 2000 block numbers. Data users must use the WATER field on Record Type S to determine if the GT-polygon is land or water. The WATER field has two values, 0 for land or 1 for water. This layer is part of the Bay Area Metropolitan Transportation Commission (MTC) GIS Maps and Data collection. This dataset is intended for researchers, students, and policy makers for reference and mapping purposes, and may be used for basic applications such as viewing, querying, and map output production, or to provide a basemap to support graphical overlays and analysis with other spatial data. California, Metropolitan Transportation Commission. (2002). Census Blocks, 2000 - San Francisco Bay Area, California. MTC. Available at: http://purl.stanford.edu/ts501wk9853. This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection.
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Title: Census Counties, 2000 - San Francisco Bay Area, California
Contributors:- Polygon data
- 2002
- California. Metropolitan Transportation Commission
- U.S. Department of Commerce, Bureau of the Census, Geography Division
Summary: This polygon shapefile displays the 9 counties for the San Francisco Bay Area of California, as of January 1, 2000. The primary legal divisions of most states are termed ''counties.'' Each county and statistically equivalent entity is assigned a three-digit Federal Information Processing Standards code that is unique within the state. These codes are assigned in alphabetical order of county or county equivalent within each state.This layer is part of the Bay Area Metropolitan Transportation Commission (MTC) GIS Maps and Data collection. This dataset is intended for researchers, students, and policy makers for reference and mapping purposes, and may be used for basic applications such as viewing, querying, and map output production, or to provide a basemap to support graphical overlays and analysis with other spatial data. California, Metropolitan Transportation Commission. (2002). Census Counties, 2000 - San Francisco Bay Area, California. MTC. Available at: http://purl.stanford.edu/hv237bh9962. This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection.
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Title: 2000 Census Traffic Analysis Zones - San Francisco Bay Area, California
Contributors:- Polygon data
- 2002
- California. Metropolitan Transportation Commission
- U.S. Department of Commerce, Bureau of the Census, Geography Division
Summary: This polygon shapefile contains the traffic analysis zones (TAZs) for the San Francisco Bay Area in California. These data have been clipped to the shoreline for cartographic representation. TAZs are special-purpose geographic entities delineated by state and local transportation officials for tabulating traffic related data from the decennial census, especially journey-to-work and place-of-work statistics. A TAZ usually consists of one or more census blocks, block groups, or census tracts. Each TAZ is identified by a 6-character alphanumeric census code that is unique within county or statistically equivalent entity. A code of ZZZZZZ indicates a portion of a county where no TAZs were defined. This layer is part of the Bay Area Metropolitan Transportation Commission (MTC) GIS Maps and Data collection. This dataset is intended for researchers, students, and policy makers for reference and mapping purposes, and may be used for basic applications such as viewing, querying, and map output production, or to provide a basemap to support graphical overlays and analysis with other spatial data. California, Metropolitan Transportation Commission. (2002). 2000 Census Traffic Analysis Zones - San Francisco Bay Area, California. MTC. Available at: http://purl.stanford.edu/tm960wp6354. This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection.
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Title: Census Blocks, 2000 - San Francisco Bay Area, California
Contributors:- Polygon data
- 2002
- California. Metropolitan Transportation Commission
- U.S. Department of Commerce, Bureau of the Census, Geography Division
Summary: This polygon shapefile represents U.S. Census Blocks for the San Francisco Bay Area of California as of the year 2000. Census blocks are statistical areas bounded on all sides by visible features such as streets, roads, streams, and railroad tracks, and by invisible boundaries such as city, town, township, and county limits, and short imaginary extensions of streets and roads. Generally census blocks are small in area; for example, a block in a city bounded by streets. However, census blocks in remote areas may be large and irregular and contain hundreds of square miles. All territory in the United States, Puerto Rico, and the Island Areas have block numbers. Blocks are composed of one or more GT-polygons; that is, several GT-polygons can share the same block number. Census 2000 Block Numbers. Census 2000 tabulation blocks are numbered uniquely within each state/county/census tract with a four-digit census block number. The U.S. Census Bureau created the tabulation block numbers immediately before beginning its Census 2000 data tabulation process, thereby eliminating block suffixes. The first digit of the tabulation block number identifies the block group. For the 1990 census, the U.S. Census Bureau assigned a unique 1990 block number with a suffix of "Z" to identify crews-of-vessels population. For Census 2000, crews-of-vessels population is assigned to the land block identified by the U.S. Census Bureau as associated with the home port of the vessel. Water Blocks. The U.S. Census Bureau introduced a different method for identifying the water areas of census blocks for Census 2000. For the 1990 census, water was not uniquely identified within a census block; instead, all water area internal to a block group was given a single block number ending in "99" (for example, in block group 1, all water was identified as block 199). A suffix was added to each 1990 water block number where the block existed in more than one tabulation entity within its block group. For Census 2000, water area located completely within the boundary of a single land block has the same block number as that land block. Water area that touches more than one land block is assigned a unique block number not associated with any adjacent land block. The U.S. Census Bureau assigned water block numbers beginning with the block group number followed by "999 " and preceding in descending order. For example, in block group 3, the block numbers assigned to water areas that border multiple land blocks are 3999, 3998, 3997, and so forth. Because some land blocks include water (ponds and small lakes), no conclusions about whether or not a block is all land or all water can be made by looking at the Census 2000 block numbers. Data users must use the WATER field on Record Type S to determine if the GT-polygon is land or water. The WATER field has two values, 0 for land or 1 for water. This layer is part of the Bay Area Metropolitan Transportation Commission (MTC) GIS Maps and Data collection This dataset is intended for researchers, students, and policy makers for reference and mapping purposes, and may be used for basic applications such as viewing, querying, and map output production, or to provide a basemap to support graphical overlays and analysis with other spatial data. California, Metropolitan Transportation Commission. (2002). Census Blocks, 2000 - San Francisco Bay Area, California. MTC. Available at: http://purl.stanford.edu/rv407ym2175. This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection.
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Title: Census Landmark Polygon Features, 2000 - San Francisco Bay Area, California
Contributors:- Polygon data
- 2002
- California. Metropolitan Transportation Commission
- U.S. Department of Commerce, Bureau of the Census, Geography Division
Summary: This polygon shapefile displays landmark features throughout the San Francisco Bay Area in California. "Landmark" is the general name given to a cartographic (or locational) landmark, a land-use area, and a key geographic location (KGL). A cartographic landmark is identified for use by an enumerator while working in the field. A land-use area is identified in order to minimize enumeration efforts in uninhabited areas or areas where human access is restricted. A key geographic location is identified in order to more accurately geocode and enumerate a place of work or residence. The predominant feature classes represented in this layer include airports or airfields, cemeteries, fraternities or sororities, state or local parks or forests, golf courses, lookout towers, educational and religious institutions. Other possible landmark features could include military installations, multi-household or transient quarters, custodial facilities, other types of transportation facilities or terminals, employment centers, open space and other special landmark designations for post offices, police stations and firehouses. The Census Bureau includes landmarks in the Census TIGER data base for locating special features and to help enumerators during field operations. The Census Bureau added landmark features on an as-needed-basis and made no attempt to ensure that all instances of a particular feature were included. The absence of a landmark does not mean that the living quarters, e.g., hospitals and group quarters associated with the landmark were excluded from the 1990 enumeration. A census feature class code (CFCC) is used to identify the most noticeable characteristic of a feature. The CFCC is applied only once to a chain or landmark with preference given to classifications that cover features that are visible to an observer and a part of the ground transportation network. Thus, a road that also is the boundary of a town would have a CFCC describing its road characteristics, not its boundary characteristics. The CFCC, as used in the TIGER/Line files, is a three-character code. The first character is a letter describing the feature class; the second character is a number describing the major category; and the third character is a number describing the minor category. Landmark (Feature Class D) is the general name given to a cartographic (or locational) landmark, a land-use area, and a key geographic location. This layer is part of the Bay Area Metropolitan Transportation Commission (MTC) GIS Maps and Data collection. This dataset is intended for researchers, students, and policy makers for reference and mapping purposes, and may be used for basic applications such as viewing, querying, and map output production, or to provide a basemap to support graphical overlays and analysis with other spatial data. California, Metropolitan Transportation Commission. (2002). Census Landmark Polygon Features, 2000 - San Francisco Bay Area, California. MTC. Available at: http://purl.stanford.edu/mw173fz6932. This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection.
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Title: Census Counties, 2000 - San Francisco Bay Area, California (Clipped)
Contributors:- Polygon data
- 2002
- California. Metropolitan Transportation Commission
- U.S. Department of Commerce, Bureau of the Census, Geography Division
Summary: This polygon shapefile displays the boundaries for the 9 counties of the San Francisco Bay Area in California as of January 1, 2000. These data have been clipped to the shoreline for cartographic representation. The primary legal divisions of most states are termed ''counties.'' Each county and statistically equivalent entity is assigned a three-digit Federal Information Processing Standards (FIPS) code that is unique within the state. These codes are assigned in alphabetical order of county or county equivalent within each state. This layer is part of the Bay Area Metropolitan Transportation Commission (MTC) GIS Maps and Data collection. This dataset is intended for researchers, students, and policy makers for reference and mapping purposes, and may be used for basic applications such as viewing, querying, and map output production, or to provide a basemap to support graphical overlays and analysis with other spatial data. California, Metropolitan Transportation Commission. (2002). Census Counties, 2000 - San Francisco Bay Area, California (Clipped). MTC. Available at: http://purl.stanford.edu/xv509rh6426. This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection.
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Title: Census Places, 1990 - San Francisco Bay Area, California (Clipped)
Contributors:- Polygon data
- 2002
- California. Metropolitan Transportation Commission
- U.S. Department of Commerce, Bureau of the Census, Geography Division
Summary: This polygon shapefile contains the Census places for the San Francisco Bay Area based as of January 1, 2000. These data have been clipped to the shoreline for cartographic representation. Places, for the reporting of decennial census data, include census designated places, consolidated cities, and incorporated places. Each place is assigned a five-digit Federal Information Processing Standards (FIPS) code. This layer is part of the Bay Area Metropolitan Transportation Commission (MTC) GIS Maps and Data collection. This dataset is intended for researchers, students, and policy makers for reference and mapping purposes, and may be used for basic applications such as viewing, querying, and map output production, or to provide a basemap to support graphical overlays and analysis with other spatial data. California, Metropolitan Transportation Commission. (2002). Census Places, 1990 - San Francisco Bay Area, California. MTC. Available at: http://purl.stanford.edu/th890tz9933. This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection.
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Title: Census Block Groups, 2000 - San Francisco Bay Area, California
Contributors:- Polygon data
- 2002
- California. Metropolitan Transportation Commission
- U.S. Department of Commerce, Bureau of the Census, Geography Division
Summary: This polygon shapefile displays U.S. Census Block Groups for the San Francisco Bay Area in California as of January 1, 2000. Block Groups (BGs) are clusters of blocks within the same census tract having the same first digit of their 4-digit census block number. For example, block group 3 (BG 3) within a census tract includes all blocks numbered from 3000 to 3999. Census 2000 BGs generally contain between 600 and 3,000 people, with an optimum size of 1,500 people. Most BGs were delineated by local participants in the U.S. Census Bureau's Participant Statistical Areas Program. The U.S. Census Bureau delineated BGs only where a local or tribal government declined to participate or where the U.S. Census Bureau could not identify a potential local 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 county subdivisions, places, urbanized areas, voting districts, congressional districts, and American Indian/Alaska Native areas/Hawaiian home lands. Under the Census 2000 American Indian/Alaska Native area/Hawaiian homeland census geographic hierarchy, census tracts and BGs are defined within American Indian entities and can cross state and county boundaries. These are commonly referred to as Tribal BGs.BGs have a valid range of 0 through 9. BGs beginning with a 0 generally are in coastal and Great Lakes water and territorial seas. Rather than extending a census tract boundary into the Great Lakes or out to the three mile territorial sea limit, the U.S. Census Bureau delineated some census tract boundaries along the shoreline or just offshore. The U.S. Census Bureau assigned a default census tract number of 0000 and BG of 0 to the offshore areas not included in regularly numbered census tract areas.In decennial census data tabulations, a block group may be split to present data for every unique combination of county subdivision, place, voting district, congressional district, American Indian area/Alaska Native area/ Hawaiian home land shown in the data tabulation products. This layer is part of the Bay Area Metropolitan Transportation Commission (MTC) GIS Maps and Data collection. This dataset is intended for researchers, students, and policy makers for reference and mapping purposes, and may be used for basic applications such as viewing, querying, and map output production, or to provide a basemap to support graphical overlays and analysis with other spatial data. California, Metropolitan Transportation Commission. (2002). Census Block Groups, 2000 - San Francisco Bay Area, California. MTC. Available at: http://purl.stanford.edu/nk081sx0125. This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection.
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Title: UA Census Miscellaneous Ground Transportation Features, 2000 - California
Contributors:- Line data
- 2002
Summary: This datalayer displays miscellaneous ground transportation features in the state of California. Features other than roads or railroads may be included in this layer. The predominant feature in this layer has a Census Feature Class Code (CFCC) of C20 -- which is classed as power transmission lines. Other features that may be included are: Pipelines: enclosed pipe, carrying fluid or slurry, situated above ground, or in special conditions, below ground when marked by a cleared right-of way and signage. Power Transmission Line: High voltage electrical line, on towers, situated on cleared right-of-way. Miscellaneous Ground Transportation With Special Characteristics: A portion of a ground transportation system that has separately identifiable characteristics. This category is for specialized transportation, usually confined to a local area, that is separate from other ground transportation. Other ground transportation that is not a pipeline or a power transmission line, such as aerial tramway, monorail, or ski lift.
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Title: UA Census Key Geographic Locations, 2000 - Iowa
Contributors:- Polygon data
- 2002
Summary: This datalayer displays Key Geographic Locations (KGLs), as defined by the US Census Bureau, throughout the state. Essential attribute data included are KGL Name and Census Feature Class Code (CFCC). Predominant features represented in this layer include: Airports or airfields; Custodial Facility (hospital, orphanage, Federal penitentiary, state prison); Educational or Religious Institution (convent or monastery, educational institution, religious institution); Multihousehold or Transient Quarters (apartment buildings and complexes, trailer courts or mobile home parks, campground, hotels, motels); Shopping centers or major retail centers; Transportation Terminal (train station, bus or marine terminal). Please note that many other feature types may be present in this layer. Key geographic locations (KGLs) represent a special class of address information. They provide a geocoding tool like address ranges, but also identify a spatial object similar to a landmark. The Census Bureau uses KGLs to identify named buildings where the use of the feature name enhances the ability to geocode addresses. These cases include airports, shopping centers, schools, condominiums, hotels, and apartment complexes. Even though the KGLs appear to identify specific structures, the KGL descriptions do not include location coordinates. In most cases, the Census Bureau can determine the general location of the KGL, but cannot provide a specific location with any certainty. The Census Bureau includes landmarks in the Census TIGER data base for locating special features and to help enumerators during field operations. The Census Bureau added landmark features on an as-needed-basis and made no attempt to ensure that all instances of a particular feature were included. The absence of a landmark does not mean that the living quarters, e.g., hospitals and group quarters associated with the landmark were excluded from the 1990 enumeration. A landmark can be a point, line, or area type. In some cases, the Census TIGER data base permits a choice of types. For instance, an airport or airfield might appear as a point, line, or area; the approach depends on the size of the feature and the depiction of the feature in the source document. Line features such as airfields could appear as one or more complete chains; they are not identified in the landmark record types A census feature class code (CFCC) is used to identify the most noticeable characteristic of a feature. The CFCC is applied only once to a chain or landmark with preference given to classifications that cover features that are visible to an observer and a part of the ground transportation network. Thus, a road that also is the boundary of a town would have a CFCC describing its road characteristics, not its boundary characteristics. The CFCC, as used in the TIGER/Line files, is a three-character code. The first character is a letter describing the feature class; the second character is a number describing the major category; and the third character is a number describing the minor category. Landmark (Feature Class D) is the general name given to a cartographic (or locational) landmark, a land-use area, and a key geographic location. A cartographic landmark is identified for use by an enumerator while working in the field. A land-use area is identified in order to minimize enumeration efforts in uninhabited areas or areas where human access is restricted. A key geographic location is identified in order to more accurately geocode and enumerate a place of work or residence.
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Title: UA Census Block Groups, 2000 - West Virginia
Contributors:- Polygon data
- 2002
Summary: The polygons represent U.S. Census Block Groups for the state based on the ground condition of January 1, 2000. Block Groups (BGs) are clusters of blocks within the same census tract having the same first digit of their 4-digit census block number. For example, block group 3 (BG 3) within a census tract includes all blocks numbered from 3000 to 3999. Census 2000 BGs generally contain between 600 and 3,000 people, with an optimum size of 1,500 people. Most BGs were delineated by local participants in the U.S. Census Bureau's Participant Statistical Areas Program. The U.S. Census Bureau delineated BGs only where a local or tribal government declined to participate or where the U.S. Census Bureau could not identify a potential local 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 county subdivisions, places, urbanized areas, voting districts, congressional districts, and American Indian/Alaska Native areas/Hawaiian home lands. Under the Census 2000 American Indian/Alaska Native area/Hawaiian homeland census geographic hierarchy, census tracts and BGs are defined within American Indian entities and can cross state and county boundaries. These are commonly referred to as Tribal BGs. BGs have a valid range of 0 through 9. BGs beginning with a 0 generally are in coastal and Great Lakes water and territorial seas. Rather than extending a census tract boundary into the Great Lakes or out to the three mile territorial sea limit, the U.S. Census Bureau delineated some census tract boundaries along the shoreline or just offshore. The U.S. Census Bureau assigned a default census tract number of 0000 and BG of 0 to the offshore areas not included in regularly numbered census tract areas. In decennial census data tabulations, a block group may be split to present data for every unique combination of county subdivision, place, voting district, congressional district, American Indian area/Alaska Native area/ Hawaiian home land shown in the data tabulation products.
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Title: UA Census Non-Visible Boundaries, 2000 - Michigan
Contributors:- Line data
- 2002
Summary: This datalayer displays the non-visible features for the state. This layer contains various types of nonvisible lines used to maintain the topology in the Census TIGER database. Non-visible features are used to delimit tabulation entities, property areas, legal and administrative entities. The U.S. Census Bureau separately identifies non-visible boundaries only when they do not follow a visible feature such as a road, stream, or ridge line. The predominant Census Feature Class Codes (CFCC) in this layer include: F10 (Non-visible jurisdictional boundary of a legal or administrative entity); F23 (Closure extension to complete database topological closure between extremely close features - used to close small gaps between complete chains and create polygons to improve block labeling on cartographic products); F40 (Property line, non-visible boundary of either public or private lands, e.g., a park boundary); F71 (1980 statistical boundary); F72 (1990 statistical boundary; used to hold 1990 collection and tabulation census block boundaries not represented by existing physical features); F73 (Internal U.S. Census Bureau use) and F81 (School district boundary).
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Title: UA Census Blocks, 1990 - West Virginia
Contributors:- Polygon data
- 2002
Summary: The polygons in this datalayer represent U.S. Census Blocks for the entire state. Census blocks are statistical areas bounded on all sides by visible features such as streets, roads, streams, and railroad tracks, and by invisible boundaries such as city, town, township, and county limits, and short imaginary extensions of streets and roads. Generally census blocks are small in area; for example, a block in a city bounded by streets. However, census blocks in remote areas may be large and irregular and contain hundreds of square miles. All territory in the United States, Puerto Rico, and the Island Areas have block numbers. Blocks are composed of one or more GT-polygons; that is, several GT-polygons can share the same block number. Census 2000 Block Numbers. Census 2000 tabulation blocks are numbered uniquely within each state/county/census tract with a four-digit census block number. The U.S. Census Bureau created the tabulation block numbers immediately before beginning its Census 2000 data tabulation process, thereby eliminating block suffixes. The first digit of the tabulation block number identifies the block group. For the 1990 census, the U.S. Census Bureau assigned a unique 1990 block number with a suffix of 'Z' to identify crews-of-vessels population. For Census 2000, crews-of-vessels population is assigned to the land block identified by the U.S. Census Bureau as associated with the home port of the vessel. Water Blocks. The U.S. Census Bureau introduced a different method for identifying the water areas of census blocks for Census 2000. For the 1990 census, water was not uniquely identified within a census block; instead, all water area internal to a block group was given a single block number ending in '99' (for example, in block group 1, all water was identified as block 199). A suffix was added to each 1990 water block number where the block existed in more than one tabulation entity within its block group. For Census 2000, water area located completely within the boundary of a single land block has the same block number as that land block. Water area that touches more than one land block is assigned a unique block number not associated with any adjacent land block. The U.S. Census Bureau assigned water block numbers beginning with the block group number followed by '999 ' and preceding in descending order. For example, in block group 3, the block numbers assigned to water areas that border multiple land blocks are 3999, 3998, 3997, and so forth. Because some land blocks include water (ponds and small lakes), no conclusions about whether or not a block is all land or all water can be made by looking at the Census 2000 block numbers. Data users must use the WATER field on Record Type S to determine if the GT-polygon is land or water. The WATER field has two values, 0 for land or 1 for water. NOTE: For additional information on this or other layers in the UA Census 2000 TIGER dataset please consult the U.S. Census Bureau's technical documentation at: http://www.census.gov/geo/www/tiger/tigerua/ua2ktgr.pdf
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Title: UA Census Unified School Districts, 2000 - Guam
Contributors:- Polygon data
- 2002
Summary: This datalayer displays the Unified School Districts for the entire state. A unified school district is inclusive of kindergarten through twelfth grade. School districts are geographic entities within which state, county, tribal, or local officials provide public educational services for the area's residents. The U.S. Census Bureau obtains the boundaries and names for school districts from state officials. The UA Census 2000 TIGER/Line files contain school district information from the 1999-2000 school year. The UA Census 2000 TIGER/Line files identify three levels of school districts representing different grade ranges of the school-age population (elementary and secondary) and a unified category to identify those school districts that represent all grade levels. The elementary and secondary levels of a school district can overlap each other because they represent different segments of the school-age population; for example, a secondary school district could cover parts of several elementary school districts. The TIGER/Line files use separate fields to accommodate for the overlap and may not contain a code for all grade levels. The TIGER/Line files contain a Unified School District code for those school districts where all grade levels are represented in a single district. The elementary and secondary school district code fields are blank if there is a unified school district code. An exception exists for the State of Hawaii and the five boroughs of New York city where the National School District Program requested that the U.S. Census Bureau include the School Complex Areas in Hawaii and the Community School Districts in New York city. In Massachusetts. South Carolina, and Tennessee some unified school districts also serve as secondary school districts in areas where there are elementary school districts. In these situations, the U.S. Census Bureau could not use the same school district code to identify school districts serving different grade ranges and has assigned two separate codes; a unified school district code and a separate 'false' secondary school district code. Data users can identify the 'false' school districts by looking for 'false' as part of the school district name appearing in Record Type C. A few additional exceptions occur where the Department of Defense operates elementary schools within a unified school district. The TIGER/Line files store the school district codes in a set of three, 5-character fields. All codes consist of numeric characters. The value, 99999, is a pseudo-school district code assigned to non-water blocks for which the National School District Program does not report a school district. Some large water areas have a pseudo-school district code of 99998.
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Title: UA Census State Legislative Districts (Lower Chamber), 2000 - South Carolina
Contributors:- Polygon data
- 2002
Summary: This layer displays the legislative districts for the lower (House of Representatives) chamber for the state. State legislative districts (SLDs) are the areas from which members are elected to state legislatures. States participating in the Census 2000 Redistricting Data Program as part of Public Law 94-171 (1975) may provide the U.S. Census Bureau with boundaries and codes for their SLDs. The U.S. Census Bureau is reporting data for SLDs for the first time for Census 2000. SLDs embody the upper (senate) and lower (house) chambers of the state legislature. A unique 1- to 3-character census code, identified by state participants, is assigned to a SLDs within each state. It is possible to have SLDs that cover only part of a state. In such instances, any areas for which SLDs are not defined are coded 'ZZZ' and treated as a single SLD for purposes of data presentation. NOTE: Nebraska has a unicameral legislature that the U.S. Census Bureau treats as an upper-chamber legislative area for purposes of data presentation. New Hampshire only submitted SLDs for the upper chamber. Therefore, there are no data by lower chamber for these two states. The following states did not participate in Phase 2 (the Voting District Project) of the Census 2000 Redistricting Data Program and no SLDs appear for these states: California; Florida; Kentucky; Montana. Of the participating states (or statistically equivalent entities), the following did not submit SLD boundaries or codes as part of Phase 2 (the Voting District Project) of the Census 2000 Redistricting Data Program, but submitted Voting Districts (VTDs) only: Arkansas; Maine; Texas; District of Columbia; Maryland; Puerto Rico; Hawaii; Minnesota.
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Title: UA Census American Indian Reservations, 2000 - Montana
Contributors:- Polygon data
- 2002
Summary: This datalayer depicts feature location and other associated data for American Indian tribal entities for those entities established on January 1, 2000. American Indian Reservations are areas that have been set aside by the United States for the use of tribes, the exterior boundaries of which are more particularly defined in the final tribal treaties, agreements, executive orders, federal statutes, secretarial orders, or judicial determinations. The U.S. Census Bureau recognizes federal reservations as territory over which American Indian tribes have primary governmental authority. These entities are known as colonies, communities, pueblos, rancherias, ranches, reservations, reserves, villages, Indian communities, and Indian villages. The Bureau of Indian Affairs (BIA) maintains a list of federally recognized tribal governments. The U.S. Census Bureau contacts representatives of American Indian tribal governments to identify the boundaries for federal reservations. Federal reservations may cross state, county, county subdivision, and place boundaries. The BIA supplied the U.S. Census Bureau with the names and exterior boundaries of the federal AIRs used for the 1990 census. The U.S. Census Bureau first reported data for American Indian reservations in the 1970 census. The range of Census Codes allocated to Federal AIRs for the year 2000 data is 0001 to 4999. There are both legal and statistical American Indian, Alaska Native, and native Hawaiian entities for which the U.S. Census Bureau provides data. The legal entities consist of federally recognized American Indian reservations and off-reservation trust land areas, the tribal subdivisions that can divide these entities, state recognized American Indian reservations, Alaska Native Regional Corporations (ANRCs), and Hawaiian home lands (HHLs). The statistical entities are Alaska Native village statistical areas (ANVSAs), Oklahoma tribal statistical areas (OTSAs), tribal designated statistical areas (TDSAs), and state designated American Indian statistical areas (SDAISAs). Tribal subdivisions can exist within the statistical Oklahoma tribal statistical areas. In all cases, these areas are mutually exclusive in that no American Indian, Alaska Native, or Hawaiian home land can overlap another tribal entity, except for tribal subdivisions, which subdivide some American Indian entities, and Alaska Native village statistical areas (ANVSAs), which exist within Alaska Native Regional Corporations (ANRCs). American Indian Trust Lands Areas for which the United States holds title in trust for the benefit of a tribe (tribal trust land) or for an individual Indian (individual trust land). Trust lands can be alienated or encumbered only by the owner with the approval of the Secretary of the Interior or his/her authorized representative. Trust lands may be located on or off a reservation. The U.S. Census Bureau recognizes and tabulates data for reservations and off-reservation trust lands because American Indian tribes have primary governmental authority over these lands. Primary tribal governmental authority generally is not attached to tribal lands located off the reservation until the lands are placed in trust. In U.S. Census Bureau data tabulations, off-reservation trust lands always are associated with a specific federally recognized reservation and/or tribal government. A tribal government appointed liaison provides the name and boundaries of their trust lands. The Bureau of Indian Affairs (BIA), an agency in the U.S. Department of the Interior, identified and provided maps of these areas for use by the U.S. Census Bureau for the 1990 census. The U.S. Census Bureau first reported data for off-reservation tribal trust lands in the 1980 census; in 1990, the trust land data included both tribal and individual trust lands. The U.S. Census Bureau does not identify fee land (or land in fee simple status) or restricted fee lands as specific geographic categories and they are not identified in the TIGER/Line files. Trust lands are assigned the same code as the reservation with which they are associated. Trust lands associated with tribes that do not have a reservation are assigned codes based on tribal name. In the TIGER/Line files, a letter code-'T' for tribal and 'I' for individual-appears in a separate field and identifies off-reservation trust lands. American Indian Reservations-State (State AIRs) Reservations established by some state governments for tribes recognized by the state. A governor-appointed state liaison provides the names and boundaries for state recognized American Indian reservations to the U.S. Census Bureau. State reservations may cross county, county subdivision, and place boundaries. The range of Census Class Codes allocated to State AIRs for the year 2000 data is 9000 to 9499. American Indian Tribal Subdivisions Administrative subdivisions of federally recognized American Indian reservations, off-reservation trust land, or Oklahoma tribal statistical areas (OTSAs). Tribal subdivisions are known as areas, chapters, communities, or districts. These entities are internal units of self-government or administration that serve social, cultural, and/or economic purposes for the American Indians on the reservations, off-reservation trust lands, or OTSAs. The U.S. Census Bureau obtains the boundary and name information for tribal subdivisions from tribal governments. The U.S. Census Bureau first provided data for American Indian tribal subdivisions in 1980 when it identified them as 'American Indian sub-reservation areas.' The U.S. Census Bureau did not provide data for American Indian tribal subdivisions in conjunction with the 1990 census. Joint Use Areas As applied to any American Indian area/Alaska Native area by the U.S. Census Bureau, means an area that is administered jointly and/or claimed by two or more American Indian tribes. The U.S. Census Bureau designates both legal and statistical joint use areas as unique geographic entities for the purpose of presenting statistical data. State Designated American Indian Statistical Areas (SDAISAs) Statistical entities for state recognized American Indian tribes that do not have a state recognized land base (reservation). SDAISAs are identified and delineated for the U.S. Census Bureau by a state liaison identified by the governor's office in each state. SDAISAs generally encompass a compact and contiguous area that contains a concentration of people who identify with a state recognized American Indian tribe and in which there is structured or organized tribal activity. A SDAISA may not be located in more than one state unless the tribe is recognized by both states, and it may not include area within an American Indian reservation, off-reservation trust land, Alaska Native village statistical area (ANVSA), tribal designated statistical area (TDSA), or Oklahoma tribal statistical area (OTSA). The U.S. Census Bureau established SDAISAs as a new geographic statistical area for Census 2000 to differentiate between state recognized tribes without a land base and federally recognized tribes without a land base. For the 1990 census, all such tribal entities had been identified as TDSAs. The range of Census Class Codes allocated to SDAISAs for the year 2000 data is 9500 to 9998. Tribal Designated Statistical Areas (TDSAs) Statistical entities identified and delineated for the U.S. Census Bureau by federally recognized American Indian tribes that do not currently have a federally recognized land base (reservation or off-reservation trust land). A TDSA generally encompasses a compact and contiguous area that contains a concentration of individuals who identify with a federally recognized American Indian tribe and in which there is structured or organized tribal activity. A TDSA may be located in more than one state, but it may not include area within an American Indian reservation, off-reservation trust land, Alaska Native village statistical area (ANVSA), or Oklahoma tribal statistical area (OTSA). The U.S. Census Bureau first reported data for TDSAs in conjunction with the 1990 census, when both federally and state recognized tribes could identify and delineate TDSAs. For Census 2000, TDSAs now apply only to federally recognized tribes. State recognized tribes without a land base, including those that were TDSAs in 1990, are identified as state designated American Indian statistical areas (SDAISAs), a new geographic entity for Census 2000. The range of Census Class Codes allocated to TDSAs for the year 2000 data is 8000 to 8999. Tribal Jurisdiction Statistical Areas (TJSAs) 1990 statistical entities identified and delineated for the 1990 census to provide a geographic frame of reference for the presentation of statistical data. 1990 TJSA boundaries were required to follow census block boundaries and were based upon the boundaries of the former reservations of federally recognized tribes in Oklahoma. TJSAs replaced the Historic Areas of Oklahoma recognized by the U.S. Census Bureau for the 1980 decennial census. The 1990 descriptive designation, TJSA, has been changed for Census 2000 to Oklahoma tribal statistical areas (OTSAs).