2015 State Geodatabase for Delaware

The 2015 TIGER Geodatabases are extracts of selected nation based and state based geographic and cartographic information from the U.S. Census Bureau's Master Address File/Topologically Integrated Geographic Encoding and Referencing (MAF/TIGER) database. The geodatabases include feature class layers of information for the fifty states, the District of Columbia, Puerto Rico, and the Island areas (American Samoa, the Commonwealth of the Northern Mariana Islands, Guam, and the United States Virgin Islands). The geodatabases do not contain any sensitive data. The 2015 TIGER Geodatabases are designed for use with Esri’s ArcGIS.

                The 2015 State Geodatabase for Delaware contains multiple layers. These layers are the Block, Block Group, Census Designated Place, Census Tract,
                County Subdivision and Incorporated Place layers.

                Block Groups (BGs) are clusters of blocks within the same census tract. Each census tract contains at least one BG, and BGs are uniquely numbered
                within census tracts.  BGs have a valid code range of 0 through 9. BGs have the same first digit of their 4-digit census block number from the same
                decennial census.  For example, tabulation blocks numbered 3001, 3002, 3003,.., 3999 within census tract 1210.02 are also within BG 3 within that
                census tract.  BGs coded 0 are intended to only include water area, no land area, and they are generally in territorial seas, coastal water, and
                Great Lakes water areas. Block groups generally contain  between 600 and 3,000 people.  A BG usually covers a contiguous area but never crosses
                county or census tract boundaries. They may, however, 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.

                The BG boundaries in this release are those that were delineated as part of the Census Bureau's Participant Statistical Areas Program (PSAP) for the
                2010 Census.

                The primary purpose of census tracts is to provide a stable set of geographic units for the presentation of census data and comparison back to
                previous decennial censuses.  Census tracts generally have a population size between 1,200 and 8,000 people, with an optimum size of 4,000 people.
                When first delineated, census tracts were designed to be homogeneous with respect to population characteristics, economic status, and living
                conditions.  The spatial size of census tracts varies widely depending on the density of settlement.  Physical changes in street patterns caused by
                highway construction, new development, and so forth, may require boundary revisions.  In addition, census tracts occasionally are split due to
                population growth, or combined as a result of substantial population decline.  Census tract boundaries generally follow visible and identifiable
                features.  They may follow legal boundaries such as minor civil division (MCD) or incorporated place boundaries in some States and situations to
                allow for census tract-to-governmental unit relationships where the governmental boundaries tend to remain unchanged between censuses.  State and
                county boundaries always are census tract boundaries in the standard census geographic hierarchy.  In a few rare instances, a census tract may
                consist of noncontiguous areas.  These noncontiguous areas may occur where the census tracts are coextensive with all or parts of legal entities
                that are themselves noncontiguous.  For the 2010 Census, the census tract code range of 9400 through 9499 was enforced for census tracts that
                include a majority American Indian population according to Census 2000 data and/or their area was primarily covered by federally recognized American
                Indian reservations and/or off-reservation trust lands; the code range 9800 through 9899 was enforced for those census tracts that contained little
                or no population and represented a relatively large special land use area such as a National Park, military installation, or a business/industrial
                park; and the code range 9900 through 9998 was enforced for those census tracts that contained only water area, no land area.

                An incorporated place is established to provide governmental functions for a concentration of people as opposed to a minor civil division (MCD),
                which generally is created to provide services or administer an area without regard, necessarily, to population.  Places always nest within a state,
                but may extend across county and county subdivision boundaries.  An incorporated place usually is a city, town, village, or borough, but can have
                other legal descriptions.  CDPs are delineated for the decennial census as the statistical counterparts of incorporated places.  CDPs are delineated
                to provide data for settled concentrations of population that are identifiable by name, but are not legally incorporated under the laws of the state
                in which they are located.  The boundaries for CDPs often are defined in partnership with state, local, and/or tribal officials and usually coincide
                with visible features or the boundary of an adjacent incorporated place or another legal entity.  CDP boundaries often change from one decennial
                census to the next with changes in the settlement pattern and development; a CDP with the same name as in an earlier census does not necessarily
                have the same boundary.  The only population/housing size requirement for CDPs is that they must contain some housing and population.

                The boundaries of most incorporated places in this shapefile are as of January 1, 2013, as reported through the Census Bureau's Boundary and
                Annexation Survey (BAS).  Limited updates that occurred after January 1, 2013, such as newly incorporated places, are also included.  The boundaries
                of all CDPs were delineated as part of the Census Bureau's Participant Statistical Areas Program (PSAP) for the 2010 Census.

                The primary legal divisions of most states are termed counties.  In Louisiana, these divisions are known as parishes.  In Alaska, which has no
                counties, the equivalent entities are the organized boroughs, city and boroughs, municipalities, and for the unorganized area, census areas.  The
                latter are delineated cooperatively for statistical purposes by the State of Alaska and the Census Bureau.  In four states (Maryland, Missouri,
                Nevada, and Virginia), there are one or more incorporated places that are independent of any county organization and thus constitute primary
                divisions of their states.  These incorporated places are known as independent cities and are treated as equivalent entities for purposes of data
                presentation.  The District of Columbia and Guam have no primary divisions, and each area is considered an equivalent entity for purposes of data
                presentation.  The Census Bureau treats the following entities as equivalents of counties for purposes of data presentation: Municipios in Puerto
                Rico, Districts and Islands in American Samoa, Municipalities in the Commonwealth of the Northern Mariana Islands, and Islands in the U.S. Virgin
                Islands.  The entire area of the United States, Puerto Rico, and the Island Areas is covered by counties or equivalent entities.

                The boundaries for counties and equivalent entities are mostly as of January 1, 2013, primarily as reported through the Census Bureau's Boundary and
                Annexation Survey (BAS).  However, some changes made after January 2013, including the addition and deletion of counties, are included.

                County subdivisions are the primary divisions of counties and their equivalent entities for the reporting of Census Bureau data. They include
                legally-recognized minor civil divisions (MCDs) and statistical census county divisions (CCDs), and unorganized territories.  For the 2010 Census,
                the MCDs are the primary governmental and/or administrative divisions of counties in 29 States and Puerto Rico; Tennessee changed from having CCDs
                for Census 2000 to having MCDs for the 2010 Census.  In MCD States where no MCD exists or is not defined, the Census Bureau creates statistical
                unorganized territories to complete coverage.  The entire area of the United States, Puerto Rico, and the Island Areas are covered by county
                subdivisions.  The boundaries of most legal MCDs are as of January 1, 2013, as reported through the Census Bureau's Boundary and Annexation Survey
                (BAS).

                The boundaries of all CCDs, delineated in 21 states, are those as reported as part of the Census Bureau's Participant Statistical Areas Program
                (PSAP) for the 2010 Census.