GIS term - Glossary
GIS Dictionary (by ESRI)
GIS Dictionary(by AGI)
SBDCNet GIServices Glossary
Age - The age classification is based on the age of the person as of April 1, 2000.
Aggregate - The total amount. For example, the Aggregate Households calculates the total number of households within a specified area.
Aggregation - A process of grouping unique data. The aggregated data set has a smaller number of elements than the input data set.
American Indian and Alaska Native - Refers to people having origins in any of the original peoples of North and South America (including Central America), and who maintain tribal affiliation or community attachment. It includes people who indicated their race or races by marking this category or writing in their principal or enrolled tribe, such as Rosebud Sioux, Chippewa, or Navajo.
Asian - Refers to people having origins in any of the original peoples of the Far East, Southeast Asia, or the Indian subcontinent. It includes people who indicated their race or races as �Asian Indian,� �Chinese,� �Filipino,� �Korean,� �Japanese,� �Vietnamese, � or �Other Asian,� or wrote in entries such as Burmese, Hmong, Pakistani, or Thai.
Average - The number found by dividing the sum of all quantities by the total number of quantities. For example, Aggregate Income divided by Total Households equals Average Household Income.
Average Income of Households - Includes the income of the householder and all other persons 15 years and over in the household, whether related to the householder or not. Because many households consists of only one person, average household income is usually less than average family income.
Average Household Income - The average or mean income is obtained by dividing total household income by the total number of households. Because the average is influenced strongly by extreme values in the distribution, it is especially susceptible to the effects of sampling variability.
Average Household Size - Average household size is calculated by dividing the number of persons in households by the number of households.
Black or African American - Refers to people having origins in any of the Black racial groups of Africa. It includes people who indicated their race or races as �Black, African Am., or Negro,� or wrote in entries such as African American, Afro American, Nigerian, or Haitian.
Census Block - The smallest geographical area, bounded by visible boundaries, for which census data are collected. Census blocks make up census block groups that make up census tracts.
Census Block Group - Subdivisions of census tracts, each generally contain between 600 and 3000 people, with an optimum size of 1,500 people.
Census Tract - A small, permanent subdivision of a county with homogeneous population characteristics, status and living conditions.
County - The primary political administrative subdivision of a state, the county is widely used for marketing purposes for the following reasons: 1) The range and reliability of currently available data below the state level is greatest at the county level. 2) County geographic boundaries are rarely altered. 3) Complete national coverage is achieved by summarizing all counties. 4) County boundaries are readily identifiable.
For Louisiana, parishes are used in lieu of counties; for Alaska, boroughs and census areas. The District of Columbia is treated as a single county unit. In Virginia, all cities are by law independent of counties; therefore they are treated as county units. The cities of Baltimore, MD, St. Louis, MO and Carson City, NV are also independent and therefore classified as counties.
Density - Population divided by the county's square miles of land area. A simple basis for relating population to a county's size. Thus, two counties with the same population can have sharply divergent densities because of difference in land area. The figure may suffer because the land area will include railroad freight yards, wildlife preserves, industrial parks and other nonresidential areas, resulting in a misleading density level.
Designated Market Area (DMA) - The formal term for what is more commonly known as a TV or broadcast market. Definitions for DMA's are supplied by Nielsen Media Research that generates ratings for broadcast programming. DMA's are selected by totaling the viewer hours of TV stations whose signals reach a particular county with total hours, then converted to a percentage share of all viewing hours. DMA's are named for the market of origin of the station(s) with the largest share of viewer hours, and all counties whose largest viewer share is given to stations in that same market of origin are grouped together under that DMA.
NOTE: Because of the reach of broadcast signals, DMA's don't always conform to whole-county geography like metro markets or newspaper markets. In certain cases, Nielsen splits counties, treating each portion as if it were a separate county. Each county, or portion thereof, is allocated to a single DMA, eliminating any geographic overlap. DMA's cover the whole U.S., except for parts of Alaska.
Disposable Income - Income available for saving or spending after taxes.
Ethnicity - In general, the Census Bureau defines ethnicity or origin as the heritage, nationality group, lineage, or country of birth of the person or the person 's parents or ancestors before their arrival in the United States. People who identify their origin as Spanish, Hispanic, or Latino may be of any race.
According to the revised Office of Management and Budget standards, race is considered a separate concept from Hispanic origin (ethnicity) and, wherever possible, separate questions should be asked on each concept. Federal Information Processing Standards (FIPS) Code - FIPS codes are assigned for a variety of geographic entities, including American Indian and Alaska Native area, congressional district, county, county subdivision, metropolitan area, place, and state. The objective of the FIPS code is to improve the use of data and avoid unnecessary duplication and incompatibilities in the collection, processing, and dissemination of data.
Gender - Male and Female population totals.
Geocoding - Geocoding is the process of assigning to a street address a latitude and longitude coordinate and/or geographic codes that associate an address to census geography-such as a block group, census tract, or county.
GIS - Geographic Information System. A computer software system with which spatial information may be captured, stored, analyzed, displayed and retrieved.
Hispanic Origin - The OMB defines Hispanic or Latino as �a person of Cuban, Mexican, Puerto Rican, South or Central American, or other Spanish culture or origin regardless of race.� In data collection and presentation, federal agencies are required to use a minimum of two ethnicities: �Hispanic or Latino � and �Not Hispanic or Latino.� For Census 2000, the questions on race and Hispanic origin were asked of every individual living in the United States. The question on Hispanic origin asked respondents if they were Spanish, Hispanic, or Latino based on self-identification.
Household - A household consists of all the people occupying a single housing unit under the 2000 Census rules. A housing unit is defined as a house, apartment, mobile home, group of rooms, or a single room that is occupied. In addition, the members of a household need not be related, and a single person living alone in a housing unit is also considered a household.
Persons who are not counted as members of households comprise those living in group quarters such as college dormitories, military barracks, rooming houses, long-term-care hospitals, nursing homes, and prisons.
Income - Income is the aggregate of wages and salaries, net farm and nonfarm self-employment income, interest, dividends, net rental and royalty income, Social Security and railroad retirement income, other retirement and disability income, public assistance income, unemployment compensation, Veterans Administration payments, alimony and child support, military family allotments, net winnings from gambling, and other periodic income.
Receipts from the following sources are not included as money income: money received from the sale of property (unless the recipient is engaged in the business of selling property); the value of income 'in kind' from food stamps, public housing subsidies, medical care, employer contributions for persons, etc.; withdrawal of bank deposits; money borrowed; tax refunds; exchange of money between relatives living in the same household; gifts and lump-sum inheritances, insurance payments, and other types of lump-sum receipts.
Income of Households - Includes the income of the householder and all other persons 15 years old and over in the household, whether related to the householder or not. Because many households consist of only one person, average household income is usually less than average family income.
Media Market - See Designated Market Area.
Median - A calculated value that divides the distribution in an area into two equal parts. One half falls above the value and one half falls below. For example, if the median age is 21, half the population is younger than 21 and the other half is older than 21.
Median Age - This measure divides the age distribution into two equal parts: one half of the cases falling below the median value and one-half above the value.
Median Income - The median represents the middle of the income, dividing the income distribution into two equal parts, one having income above the median and the other having income below the median.
Metropolitan Statistical Area - A geographic area with a significant population nucleus, along with any adjacent communities that have a high degree of economic and social integration with that nucleus.
Native Hawaiian and Other Pacific Islander - Refers to people having origins in any of the original peoples of Hawaii, Guam, Samoa, or other Pacific Islands. It includes people who indicated their race or races as �Native Hawaiian,� �Guamanian or Chamorro,� �Samoan,� or �Other Pacific Islander, �or wrote in entries such as Tahitian, Mariana Islander, or Chuukese.
New England County Metropolitan Area (NECMA) - The U.S. Office of Information and Regulatory Affairs (OIRA), a division of the government's Office of Management and Budget, designates these alternative areas, composed of whole counties, in the six New England states for use with data not available below the county level. A NECMA includes, in addition to the county containing the principal central city of an MSA, any other county with at least half its population in that MSA.
Other Race - Includes all other persons not included in the White, Black, American Indian, Eskimo or Aleut and Asian or Pacific Islander race categories. Persons reporting in the "Other Race" category and providing write-in entries such as multiracial, multiethnic, mixed, interracial, Wesort, or a Spanish/Hispanic origin group (such as Mexican, Cuban, or Puerto Rican) are included here.
Percent Change in Population - The percent change between April 1, 2000 (Census) and the current year's estimate or the percent change between the current's year's estimate and the projected five year estimate.
Population - Updated from the 2000 Census of Population and Housing, total Population is a head count estimate of all people living in a given geographic area. It includes people living in group quarters, such as colleges, hospitals, institutions, and nursing homes, as well as armed forces personnel permanently assigned to the area.
Population By Age and Sex - Male and female population totals for 11 age groups are useful for marketers who seek to aim their products or services at specific sales targets. For example, the 12- to 17-year-old population is a favorite target of those marketing soft drinks and compact disks. Several of the age groups are also associated with lifestyle stages such as the preschoolers (0-5 years), teenagers (12-17 years), and young adults (18-24 years), which are critical to the formulation of marketing strategies.
PSYTE - a segmentation system that classifies U.S. neighborhoods into 65 unique lifestyle segments developed through statistical clustering methods.
Race - Race is a self-identification data item in which respondents choose the race or races with which they most closely identify. People who felt they fell into none of those categories could choose the "other" option, or they could indicate a combination of more than one race. These categories differ from 1990 principally because Asian has become a separate category and because multiple races was not an option 10 years ago. Note that The Census Bureau considers "Hispanic" an ethnicity, not a race. Anyone who selected a race on their 2000 Census forms also reported whether they were Hispanic or non-Hispanic.
Stability (% in current residence 5+ years) � The Percent of housing units occupied by the same family 5 years prior to the census.
Television Market - See Designated Market Area (DMA).
Total Income - The algebraic sum of the amounts reported separately for wage or salary income; net nonfarm self-employment income; net farm self-employment income; interest, dividend, or net rental or royalty income; Social Security or railroad retirement income, public assistance or welfare income; retirement or disability income; and all other income. See Income.
Turnover (% Annual Residential Turnover) � The Percent of households who moved in the past year.
Two or More Races - The two or more races category represents all those respondents who reported more than one race. This included 57 possible combinations of the six race categories defined under "Race." The decision to use the instruction "mark one or more races" was reached by the Office of Management and Budget in 1997 after noting evidence of increasing numbers of children from interracial unions and the need to measure the increased diversity in the United States. Prior to this decision, most efforts to collect data on race (including those by the Census Bureau) asked people to report one race.
Vintage - The date that the map or data was created or updated.
White - Refers to people having origins in any of the original peoples of Europe, the Middle East, or North Africa. It includes people who indicated their race or races as �White �or wrote in entries such as Irish, German, Italian, Lebanese, Near Easterner, Arab, or Polish.
ZIP Code - Administrative units established by the United States Postal Service (USPS) for the efficient distribution of mail. ZIP Codes generally do not respect political or census statistical area boundaries, nor do they usually have clearly identifiable boundaries. In addition, ZIP Codes often serve a continually changing area, are changed periodically to meet postal requirements and do not cover all the land area of the United States. The first three digits of the five-digit code identify a major city or sectional distribution center while the last two digits signify a specific post office delivery area or point. Note: The ZIP code data provided is obtained from the U.S. Census geography �ZCTA� (ZIP Code Tabulation Areas).
