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Glossary

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    12057
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    Glossary Entries
    Word(s) Definition Image Caption Link Source
    Active satellites Remote sensors that detect reflected responses from objects that are irradiated from artificially generated energy sources.        
    append A geoprocessing technique that combines adjacent polygon datasets into a single dataset.        
    arcs A one-dimensional object composed of multiple, explicitly connected points. Lines have the property of length. Also called a “line.”        
    ArcSDE geodatabase A type of geodatabase developed to allow multiple editors to simultaneously work on feature datasets within a single geodatabase.        
    area definition The topological property stating that line segments connect to surround an area and define a polygon.        
    areas A two-dimensional feature created from multiple lines that loop back to create a “closed” feature. Areas have the properties of area and perimeter. Also called “polygons.”        
    areas A two-dimensional feature created from multiple lines that loop back to create a “closed” feature. Areas have the properties of area and perimeter. Also called “polygons.”        
    Aspect maps A map depicting rasterized aspect values throughout its extent.        
    Aspect maps A map depicting rasterized aspect values throughout its extent.        
    attribute accuracy The difference between information as recorded in an attribute table and the real-world features they represent.        
    attribute accuracy The difference between information as recorded in an attribute table and the real-world features they represent.        
    attribute data Data that describe the qualities and characteristics of a particular phenomena.        
    attribute data Data that describe the qualities and characteristics of a particular phenomena.        
    attributes The characteristics and qualities of features and phenomena located on the surface of the earth.        
    attributes The characteristics and qualities of features and phenomena located on the surface of the earth.        
    AutoCAD DXF (Drawing Interchange Format or Drawing Exchange Format) A vector file format developed by Autodesk to allow interchange between engineering-based CAD (computer-aided design) software and other mapping software packages.        
    AutoCAD DXF (Drawing Interchange Format or Drawing Exchange Format) A vector file format developed by Autodesk to allow interchange between engineering-based CAD (computer-aided design) software and other mapping software packages.        
    Boolean A data type whose values can be either true or false (1 or 0).        
    Boolean A data type whose values can be either true or false (1 or 0).        
    Boolean operators A construct that performs a logical comparison.        
    Boolean operators A construct that performs a logical comparison.        
    cadastral map A cadastral map shows the boundaries and ownership of land parcel.        
    cadastral map A cadastral map shows the boundaries and ownership of land parcel.        
    cartography The formal study of maps, mapping and map making.        
    cartography The discipline concerned with the conception, production, dissemination, and study of maps in all forms.        
    centroid A point at the geometric center of a polygon. This can be used to represent a polygon as a point.        
    centroid A point at the geometric center of a polygon. This can be used to represent a polygon as a point.        
    Choropleth maps A mapping technique that uses graded differences in shading, color, or symbolology to define average values of some property or quantity.        
    Choropleth maps A mapping technique that uses graded differences in shading, color, or symbolology to define average values of some property or quantity.        
    clause A grammatical unit in SQL.        
    clause A grammatical unit in SQL.        
    clip A geoprocessing operation that extracts those features from an input point, line, or polygon layer that falls within the spatial extent of a clip layer.        
    clip A geoprocessing operation that extracts those features from an input point, line, or polygon layer that falls within the spatial extent of a clip layer.        
    cluster tolerance A geoprocessing setting that forces nearby vertices to be snapped together if they fall within a user-specified distance.        
    cluster tolerance A geoprocessing setting that forces nearby vertices to be snapped together if they fall within a user-specified distance.        
    CMYK The cyan-magenta-yellow-black color model.        
    CMYK The cyan-magenta-yellow-black color model.        
    color wheel A visual representation of colors arranged according to their chromatic relationships.        
    color wheel A visual representation of colors arranged according to their chromatic relationships.        
    connectivity The topological property of lines sharing a common node.        
    connectivity The topological property of lines sharing a common node.        
    Contiguity The topological property of identifying adjacent polygons by recording the left and right side of each line segment.        
    Contiguity The topological property of identifying adjacent polygons by recording the left and right side of each line segment.        
    continuous data Data that can take on an infinite number of potential values.        
    continuous data Data that can take on an infinite number of potential values.        
    Continuous features Phenomena that lack clearly defined boundaries.        
    Continuous features Phenomena that lack clearly defined boundaries.        
    Cool colors The greens and blues of the color spectrum associated with water, sky, ice, and cooler temperatures.        
    Cool colors The greens and blues of the color spectrum associated with water, sky, ice, and cooler temperatures.        
    coverage A georelational file format developed by ESRI that supports multiple features types (e.g., points, lines, polygons, annotations) while also storing the topological information associated with those features.        
    coverage A georelational file format developed by ESRI that supports multiple features types (e.g., points, lines, polygons, annotations) while also storing the topological information associated with those features.        
    Crowdsourcing The collection and reporting of spatial data by a diffuse user community.        
    Crowdsourcing The collection and reporting of spatial data by a diffuse user community.        
    customer/end-user The customer/end-user, which may or may not be the sponsor/client, is the person or people who will use the service or product.        
    customer/end-user The customer/end-user, which may or may not be the sponsor/client, is the person or people who will use the service or product.        
    data completeness The trait of a dataset comprehensively including all features required to ensure accurate mapping results.        
    data completeness The trait of a dataset comprehensively including all features required to ensure accurate mapping results.        
    data source A map element that provides an attribution describing where the data can be found.        
    data source A map element that provides an attribution describing where the data can be found.        
    database A collection of multiple files used to collect, organize, and analyze data.        
    database A collection of multiple files used to collect, organize, and analyze data.        
    database management system (DBMS) A software package that allows for the creation, storage, maintenance, manipulation, and retrieval of large datasets distributed over one or more files.        
    database management system (DBMS) A software package that allows for the creation, storage, maintenance, manipulation, and retrieval of large datasets distributed over one or more files.        
    Descriptive statistics Presenting data in the form of tables and charts or summarizing data through the use of simple mathematical equations.        
    Descriptive statistics Presenting data in the form of tables and charts or summarizing data through the use of simple mathematical equations.        
    digital surface models (DSMs) USGS DEMs that include the heights of landscape features such as buildings and trees.        
    digital surface models (DSMs) USGS DEMs that include the heights of landscape features such as buildings and trees.        
    digitization The conversion of analog information to digital information.        
    digitization The conversion of analog information to digital information.        
    Direction The position of a feature of phenonmenon on the surface of the earth relative to something else.        
    Direction The position of a feature of phenonmenon on the surface of the earth relative to something else.        
    dissolve A geoprocessing technique that removes the boundary between adjacent polygons with identical values.        
    dissolve A geoprocessing technique that removes the boundary between adjacent polygons with identical values.        
    Distance The amount of separation between locations.        
    Distance The amount of separation between locations.        
    DLGs (Digital Line Graphics) The vector file format developed by the USGS that maintains information on physical and cultural features across the United States.        
    DLGs (Digital Line Graphics) The vector file format developed by the USGS that maintains information on physical and cultural features across the United States.        
    double precision floating-point A floating-point data value occupying 64 bits, characterized by up to 11 bits to the left of the decimal and up to 52 bit values to the right of the decimal point.        
    double precision floating-point A floating-point data value occupying 64 bits, characterized by up to 11 bits to the left of the decimal and up to 52 bit values to the right of the decimal point.        
    DRGs (Digital Raster Graphics) Raster versions of USGS topographic maps that include all of the collar material from the originals.        
    DRGs (Digital Raster Graphics) Raster versions of USGS topographic maps that include all of the collar material from the originals.        
    DTED (Digital Terrain Elevation Data) An elevation specific raster file format developed for military purposes such as line-of-sight analysis, 3-D visualization, and mission planning.        
    DTED (Digital Terrain Elevation Data) An elevation specific raster file format developed for military purposes such as line-of-sight analysis, 3-D visualization, and mission planning.        
    Dynamic maps Interactive and changeable representations of the earth and its resident phenomena.        
    Dynamic maps Interactive and changeable representations of the earth and its resident phenomena.        
    ECW (Enhanced Compression Wavelet) A raster file format developed by Earth Resource Mapping that supports up to 255 layers of image information and includes georeferencing information within the file structure.        
    ECW (Enhanced Compression Wavelet) A raster file format developed by Earth Resource Mapping that supports up to 255 layers of image information and includes georeferencing information within the file structure.        
    equal interval A choropleth mapping technique that sets the value ranges in each category to an equal size.        
    equal interval A choropleth mapping technique that sets the value ranges in each category to an equal size.        
    erase A geoprocessing operation that preserves only those areas outside the extent of an erase layer.        
    erase A geoprocessing operation that preserves only those areas outside the extent of an erase layer.        
    Error propagation When inaccuracies are present in the original input and overlay layers and are carried through to an output layer.        
    Error propagation When inaccuracies are present in the original input and overlay layers and are carried through to an output layer.        
    file geodatabase A type of geodatabase that allows only single-user editing for unique feature datasets within a geodatabase.        
    file geodatabase A type of geodatabase that allows only single-user editing for unique feature datasets within a geodatabase.        
    first normal form The first stage in the normalization of a relational database in which repeating groups and attributes are eliminated by placing them into a separate tables connected via primary keys and foreign keys.        
    first normal form The first stage in the normalization of a relational database in which repeating groups and attributes are eliminated by placing them into a separate tables connected via primary keys and foreign keys.        
    foreign key The attribute that corresponds to a primary key in an associated table.        
    foreign key The attribute that corresponds to a primary key in an associated table.        
    geocoding Assigning latitude and longitude to phenonmena on the earth’s surface.        
    geocoding Assigning latitude and longitude to phenonmena on the earth’s surface.        
    geodatabase A recently developed, proprietary ESRI file format that supports both vector and raster feature datasets (e.g., points, lines, polygons, annotation, JPEG, TIFF) within a single file.        
    geodatabase A recently developed, proprietary ESRI file format that supports both vector and raster feature datasets (e.g., points, lines, polygons, annotation, JPEG, TIFF) within a single file.        
    geographic association Refers to how things are related to each other in space.        
    geographic association Refers to how things are related to each other in space.        
    geographic change Refers to the persistence, transformation, or disappearance of phenomena on the earth.        
    geographic change Refers to the persistence, transformation, or disappearance of phenomena on the earth.        
    geographic coordinate system (GCS) The three-dimensional coordinate system commonly used to define locations on the earth’s surface.        
    geographic coordinate system (GCS) The three-dimensional coordinate system commonly used to define locations on the earth’s surface.        
    geographic distribution Describes how phenonmena are spread across the surface of the earth.        
    geographic distribution Describes how phenonmena are spread across the surface of the earth.        
    geographic information science (GIScience) The academic field that is concerned with advancing knowledge about geographic information.        
    geographic information science (GIScience) The academic field that is concerned with advancing knowledge about geographic information.        
    geographic interaction Describes the linkages and relationships bewteen places.        
    geographic interaction Describes the linkages and relationships bewteen places.        
    geographic location The position of a phenomenon on the surface of the earth.        
    geographic location The position of a phenomenon on the surface of the earth.        
    Geoprocessing Any operation used to manipulate spatial data.        
    Geoprocessing Any operation used to manipulate spatial data.        
    geospatial metadata A special class of metadata that contains information about the geographic qualities of a data set.        
    geospatial metadata A special class of metadata that contains information about the geographic qualities of a data set.        
    geospatial PDF (Portable Document Format) A nonproprietary file format developed by Adobe Systems, Inc., that allows for the representation of geometric entities such as points, lines, and polygons.        
    geospatial PDF (Portable Document Format) A nonproprietary file format developed by Adobe Systems, Inc., that allows for the representation of geometric entities such as points, lines, and polygons.        
    Global operations Operations performed over the entire extent of a dataset.        
    Global operations Operations performed over the entire extent of a dataset.        
    global positioning system (GPS) The network of satellites orbitting the earth, transmitting signals from which latitude and longitude can be obtained with GPS units.        
    global positioning system (GPS) The network of satellites orbitting the earth, transmitting signals from which latitude and longitude can be obtained with GPS units.        
    graticule A series of grid lines representing latitude and longitude.        
    graticule A series of grid lines representing latitude and longitude.        
    Heads-up digitizing A manual data capture method whereby a user traces the outlines of features on a computer screen.        
    Heads-up digitizing A manual data capture method whereby a user traces the outlines of features on a computer screen.        
    hillshade map A map showing relative relief based on elevation of the desired area, the illumination source of which can be rotated and tilted to any desired angle for viewing.        
    hillshade map A map showing relative relief based on elevation of the desired area, the illumination source of which can be rotated and tilted to any desired angle for viewing.        
    histogram A bar graph that represents the frequency of values of a quantity by vertical rectangles of varying heights and widths.        
    histogram A bar graph that represents the frequency of values of a quantity by vertical rectangles of varying heights and widths.        
    HSV The hue-saturation-value color model.        
    HSV The hue-saturation-value color model.        
    identity An overlay method that creates an output layer with the spatial extent of the input layer but includes attribute information from an overlay.        
    identity An overlay method that creates an output layer with the spatial extent of the input layer but includes attribute information from an overlay.        
    index grid A polygon outline showing the location and extent of each map in the series.        
    index grid A polygon outline showing the location and extent of each map in the series.        
    information Knowledge and insights that are acquired through the analysis of data.        
    information Knowledge and insights that are acquired through the analysis of data.        
    Insets A map within a map.        
    Insets A map within a map.        
    integer A numerical data value that does not contain decimal digits.        
    integer A numerical data value that does not contain decimal digits.        
    interpolation A potentially complex statistical technique that estimates the value of all unknown points between the known points.        
    interpolation A potentially complex statistical technique that estimates the value of all unknown points between the known points.        
    interquartile range The difference between the first quartile (25th percentile) and the third quartile (75th percentile) of a set of ordered data.        
    interquartile range The difference between the first quartile (25th percentile) and the third quartile (75th percentile) of a set of ordered data.        
    intersection An overlay method that contains common features and attributes from both the input and overlay layers.        
    intersection An overlay method that contains common features and attributes from both the input and overlay layers.        
    interval data A data scale based on values with equal intervals but with no meaningful zero.        
    interval data A data scale based on values with equal intervals but with no meaningful zero.        
    join An operation that appends the information of one table into a second table through the use of an attribute or field that is common to both tables.        
    join An operation that appends the information of one table into a second table through the use of an attribute or field that is common to both tables.        
    KML (Keyhole Markup Language) An open-source hybrid file format developed for Google Earth.        
    KML (Keyhole Markup Language) An open-source hybrid file format developed for Google Earth.        
    Kriging A complex geostatistical technique that employs semivariograms to interpolate the values of an input point layer and is more akin to a regression analysis.        
    Kriging A complex geostatistical technique that employs semivariograms to interpolate the values of an input point layer and is more akin to a regression analysis.        
    labels Text on a map that describes and defines mapped features.        
    labels Text on a map that describes and defines mapped features.        
    leader lines A thin line that ties a label to the symbol it describes.        
    leader lines A thin line that ties a label to the symbol it describes.        
    leading A typographic effect that alters the vertical distance between lines of text.        
    leading A typographic effect that alters the vertical distance between lines of text.        
    legend A map element that describes the colors and symbols found on the map.        
    legend A map element that describes the colors and symbols found on the map.        
    line-in-polygon overlay An overlay technique in which each line that has any part of its extent within the overlay polygon layer will be included in an output line layer.        
    line-in-polygon overlay An overlay technique in which each line that has any part of its extent within the overlay polygon layer will be included in an output line layer.        
    line-on-line overlay An overlay technique in which output from this operation is a point(s) located at the intersection(s) of the two linear datasets.        
    line-on-line overlay An overlay technique in which output from this operation is a point(s) located at the intersection(s) of the two linear datasets.        
    Local operations Operations performed on a single, target cell.        
    Local operations Operations performed on a single, target cell.        
    Location Position on the surface of the earth.        
    Location Position on the surface of the earth.        
    logical consistency A trait exhibited by data that is topologically correct.        
    logical consistency A trait exhibited by data that is topologically correct.        
    Long integers An integer characterized by a 32-bit value.        
    Long integers An integer characterized by a 32-bit value.        
    Lossy compression A method to reduce the file size of an image by exploiting limitations of the human eye through removal of information from that cannot be sensed.        
    Lossy compression A method to reduce the file size of an image by exploiting limitations of the human eye through removal of information from that cannot be sensed.        
    map abstraction The process by which real-world phenomena are transformed into features on a map.        
    map abstraction The process by which real-world phenomena are transformed into features on a map.        
    Map generalization The process by which real-world features are simplified in order to be represented on a map.        
    Map generalization The process by which real-world features are simplified in order to be represented on a map.        
    map legend A common component of a map that facilitiates interpretation and understanding.        
    map legend A common component of a map that facilitiates interpretation and understanding.        
    Map projections The mathematical formulae used to tranform locations from a three-dimensional, spherical coordinate system to a two-dimensional planar system.        
    Map projections The mathematical formulae used to tranform locations from a three-dimensional, spherical coordinate system to a two-dimensional planar system.        
    Map scale The factor by which phenomena on the surface of the earth are reduced in order to be shown on a map.        
    Map scale The factor by which phenomena on the surface of the earth are reduced in order to be shown on a map.        
    mapped area The primary geographic component of the overall map.        
    mapped area The primary geographic component of the overall map.        
    mathematical raster overlay Pixel or grid cell values in each map are combined using mathematical operators to produce a new value in the composite map.        
    mathematical raster overlay Pixel or grid cell values in each map are combined using mathematical operators to produce a new value in the composite map.        
    mean The mathematical average of a set of numbers.        
    mean The mathematical average of a set of numbers.        
    median The value lying at the midpoint of a frequency distribution of observed values.        
    median The value lying at the midpoint of a frequency distribution of observed values.        
    mental maps Maps of the environment stored in our brains.        
    mental maps Maps of the environment stored in our brains.        
    merge To combine adjacent or overlapping spatial features into a single feature.        
    merge To combine adjacent or overlapping spatial features into a single feature.        
    metadata Data and information that describe data.        
    metadata Data and information that describe data.        
    MrSID (Multiresolution Seamless Image Database) A raster format developed by LizardTech, Inc., for use with large aerial photographs or satellite images, whereby portions of a compressed image can be viewed quickly without having to decompress the entire file.        
    MrSID (Multiresolution Seamless Image Database) A raster format developed by LizardTech, Inc., for use with large aerial photographs or satellite images, whereby portions of a compressed image can be viewed quickly without having to decompress the entire file.        
    natural breaks (or Jenks) A choropleth mapping technique that places class breaks in gaps between clusters of values.        
    natural breaks (or Jenks) A choropleth mapping technique that places class breaks in gaps between clusters of values.        
    navigation The destination-oriented travel through space.        
    navigation The destination-oriented travel through space.        
    neat lines A bounding line that surrounds a single map element.        
    neat lines A bounding line that surrounds a single map element.        
    Neighborhood operations Operations performed on a central, target cell and surrounding cells.        
    Neighborhood operations Operations performed on a central, target cell and surrounding cells.        
    nominal A data scale that records the name of features but that does not allow for numerical, scalar comparisons between one object and another.        
    nominal A data scale that records the name of features but that does not allow for numerical, scalar comparisons between one object and another.        
    Ordinal data A data scale that places attribute information into ranks.        
    Ordinal data A data scale that places attribute information into ranks.        
    Orthophotos Vertical photographs that have been geometrically “corrected” to remove the curvature and terrain-induced error from images.        
    Orthophotos Vertical photographs that have been geometrically “corrected” to remove the curvature and terrain-induced error from images.        
    overlay The process of integrating two or more map layers on the same map.        
    overlay The process of integrating two or more map layers on the same map.        
    overlay The process of taking two or more different thematic maps of the same area and placing them on top of one another to form a new map.        
    overlay The process of taking two or more different thematic maps of the same area and placing them on top of one another to form a new map.        
    Passive satellites Remote sensors that detect the reflected or emitted electromagnetic radiation from natural sources.        
    Passive satellites Remote sensors that detect the reflected or emitted electromagnetic radiation from natural sources.        
    personal geodatabase A type of geodatabase developed for single-user editing, whereby two editors cannot work on the same geodatabase at a given time.        
    personal geodatabase A type of geodatabase developed for single-user editing, whereby two editors cannot work on the same geodatabase at a given time.        
    pictograms A picture that represents a word or an idea by illustration.        
    pictograms A picture that represents a word or an idea by illustration.        
    PNG (Portable Network Graphics) Raster image format that stores 24-bit values for each of the red, blue, and green colors spaces.        
    PNG (Portable Network Graphics) Raster image format that stores 24-bit values for each of the red, blue, and green colors spaces.        
    point-in-polygon overlay An overlay technique that creates an output point layer that includes all the points occurring within the spatial extent of the overlay layer.        
    point-in-polygon overlay An overlay technique that creates an output point layer that includes all the points occurring within the spatial extent of the overlay layer.        
    polygon-in-polygon overlay An overlay technique in which a polygon input and overlay layers are combined to create an output polygon layer with the extent of the overlay.        
    polygon-in-polygon overlay An overlay technique in which a polygon input and overlay layers are combined to create an output polygon layer with the extent of the overlay.        
    polygon-on-line overlay An overlay technique in which polygon features that overlay lines are selected and subsequently preserved in an output layer.        
    polygon-on-line overlay An overlay technique in which polygon features that overlay lines are selected and subsequently preserved in an output layer.        
    polygon-on-point overlay An overlay technique that creates a polygon layer from those input polygons that overlay features in a point layer.        
    polygon-on-point overlay An overlay technique that creates a polygon layer from those input polygons that overlay features in a point layer.        
    Positional accuracy The probability of a feature being within +/− units of either its true location on earth (absolute positional accuracy) or its location in relation to other mapped features (relative positional accuracy).        
    Positional accuracy The probability of a feature being within +/− units of either its true location on earth (absolute positional accuracy) or its location in relation to other mapped features (relative positional accuracy).        
    positive spatial autocorrelation The result of similar values occurring near by each other.        
    positive spatial autocorrelation The result of similar values occurring near by each other.        
    Precision The variance of a value when repeated measurements are taken.        
    Precision The variance of a value when repeated measurements are taken.        
    Primary data capture A direct data acquisition methodology that is associated with an in-the-field effort.        
    Primary data capture A direct data acquisition methodology that is associated with an in-the-field effort.        
    project management knowledge areas Project management knowledge areas represent those subject areas that managers must be cognizant of to ensure that all the goals of the project will be met.        
    project management knowledge areas Project management knowledge areas represent those subject areas that managers must be cognizant of to ensure that all the goals of the project will be met.        
    proportional symbols Symbols whose size are directly related to the value of the data point being symbolized.        
    proportional symbols Symbols whose size are directly related to the value of the data point being symbolized.        
    proprietary data Data that must be purchased and are subject to certain terms of use.        
    proprietary data Data that must be purchased and are subject to certain terms of use.        
    public data Data that can be shared and distributed freely.        
    public data Data that can be shared and distributed freely.        
    Quad-tree raster encoding A method used to encode raster images by dividing the raster into a hierarchy of quadrants that are subdivided based on similarly valued pixels.        
    Quad-tree raster encoding A method used to encode raster images by dividing the raster into a hierarchy of quadrants that are subdivided based on similarly valued pixels.        
    quantile A choropleth mapping technique that classifies data into a predefined number of categories with an equal number of units in each category.        
    quantile A choropleth mapping technique that classifies data into a predefined number of categories with an equal number of units in each category.        
    Queries Searches or inquiries.        
    Queries Searches or inquiries.        
    radiometric resolution The sensitivity of a remote sensor to variations in brightness.        
    radiometric resolution The sensitivity of a remote sensor to variations in brightness.        
    range The difference between the highest and lowest values in a dataset.        
    range The difference between the highest and lowest values in a dataset.        
    range graded Grouping raw data into classes with each class represented by a differently sized symbol.        
    range graded Grouping raw data into classes with each class represented by a differently sized symbol.        
    Ratio data A data scale based on values with equal intervals and a meaningful zero.        
    Ratio data A data scale based on values with equal intervals and a meaningful zero.        
    reference map The family of maps that are used to locate features on the surface of the earth.        
    reference map The family of maps that are used to locate features on the surface of the earth.        
    relate An operation that temporarily associates two attribute tables through the use of an attribute or field that is common to both tables while keeping the tables physically separate.        
    relate An operation that temporarily associates two attribute tables through the use of an attribute or field that is common to both tables while keeping the tables physically separate.        
    relational database A database model that relates information across multiple tables according to primary and foreign keys.        
    relational database A database model that relates information across multiple tables according to primary and foreign keys.        
    relational database management system (RDBMS) A software package that records information in such a way that data can be accessed without reorganization of the tables.        
    relational database management system (RDBMS) A software package that records information in such a way that data can be accessed without reorganization of the tables.        
    relational raster overlay Pixel or grid cell values in each map are combined using relational operators to produce a new value in the composite map.        
    relational raster overlay Pixel or grid cell values in each map are combined using relational operators to produce a new value in the composite map.        
    RGB The red-green-blue color model.        
    RGB The red-green-blue color model.        
    scale A map element that describes the map dimensions.        
    scale A map element that describes the map dimensions.        
    second normal form The second stage in the normalization of a relational database in which all nonkey attributes are made dependent on the primary key.        
    second normal form The second stage in the normalization of a relational database in which all nonkey attributes are made dependent on the primary key.        
    secondary data Data that are collected by someone else or a different party.        
    secondary data Data that are collected by someone else or a different party.        
    Secondary data capture An indirect data acquisition methodology that utilizes the vast amount of existing data available in both digital and hard-copy formats.        
    Secondary data capture An indirect data acquisition methodology that utilizes the vast amount of existing data available in both digital and hard-copy formats.        
    select To define a subset of the larger set of data points or locales.        
    select To define a subset of the larger set of data points or locales.        
    Selection A defined subset of the larger set of data points or locales.        
    Selection A defined subset of the larger set of data points or locales.        
    serif A typeface in which each character has small strokes at the ends of the lines that form it. Serifs are found in typestyles such as Times New Roman, Palatino, Garamond, and Baskerville.        
    serif A typeface in which each character has small strokes at the ends of the lines that form it. Serifs are found in typestyles such as Times New Roman, Palatino, Garamond, and Baskerville.        
    Setback buffers A buffer around a polygon feature that only extends inside of the polygon boundary.        
    Setback buffers A buffer around a polygon feature that only extends inside of the polygon boundary.        
    shapefile A common set of files used by many geographic information system (GIS) software programs that contain both spatial and attribute data.        
    shapefile A common set of files used by many geographic information system (GIS) software programs that contain both spatial and attribute data.        
    shapefile A simple, nontopological, vector file format developed by ESRI to store the geometric location and attribute information of geographic features.        
    shapefile A simple, nontopological, vector file format developed by ESRI to store the geometric location and attribute information of geographic features.        
    sliver A narrow gap formed when the shared boundary of two polygons do not meet exactly.        
    sliver A narrow gap formed when the shared boundary of two polygons do not meet exactly.        
    Slope maps A map depicting rasterized slope values throughout its extent.        
    Slope maps A map depicting rasterized slope values throughout its extent.        
    space The conceptual expanse or void that is filled with geographic phenomena.        
    space The conceptual expanse or void that is filled with geographic phenomena.        
    spaghetti data model A data model in which each point, line, and/or polygon feature is represented as a string of X, Y coordinate pairs with no inherent structure.        
    spaghetti data model A data model in which each point, line, and/or polygon feature is represented as a string of X, Y coordinate pairs with no inherent structure.        
    spatial resolution The smallest distance between two adjacent features that can be detected in an image.        
    spatial resolution The smallest distance between two adjacent features that can be detected in an image.        
    spatial resolution The smallest distance between two adjacent features that can be detected in an image.        
    spatial resolution The smallest distance between two adjacent features that can be detected in an image.        
    Spectral resolution The ability of a sensor to resolve wavelength intervals, also called bands, within the electromagnetic spectrum.        
    Spectral resolution The ability of a sensor to resolve wavelength intervals, also called bands, within the electromagnetic spectrum.        
    split A geoprocessing operation that divides an input layer into two or more layers based on a split layer.        
    split A geoprocessing operation that divides an input layer into two or more layers based on a split layer.        
    SQL (Structured Query Language) A programming language designed to manage data in a relational database.        
    SQL (Structured Query Language) A programming language designed to manage data in a relational database.        
    Standard deviation A measure of the dispersion of a set of data from its mean.        
    Standard deviation A measure of the dispersion of a set of data from its mean.        
    sun-synchronous satellites Satellites that synchronize a near-polar orbit with the sun’s illumination.        
    sun-synchronous satellites Satellites that synchronize a near-polar orbit with the sun’s illumination.        
    symbolization The use of various text, icons, and symbols to represent real-world features.        
    symbolization The use of various text, icons, and symbols to represent real-world features.        
    symmetrical difference An overlay method that contains those areas common to only one of the feature datasets.        
    symmetrical difference An overlay method that contains those areas common to only one of the feature datasets.        
    Tablet digitizing A manual data capture method whereby a user enters coordinate information into a computer through the use of a digitizing tablet and a digitizing puck.        
    Tablet digitizing A manual data capture method whereby a user enters coordinate information into a computer through the use of a digitizing tablet and a digitizing puck.        
    target cell Cell found in the center of the 3-by-3 moving window.        
    target cell Cell found in the center of the 3-by-3 moving window.        
    Temporal accuracy The potential error related to the age or timeliness of a dataset.        
    Temporal accuracy The potential error related to the age or timeliness of a dataset.        
    Temporal resolution The amount of time between each image collection period determined by the repeat cycle of a satellite’s orbit.        
    Temporal resolution The amount of time between each image collection period determined by the repeat cycle of a satellite’s orbit.        
    terrain (elevation) analysis Vector or raster dataset that contains an attribute value for every locale throughout its extent.        
    terrain (elevation) analysis Vector or raster dataset that contains an attribute value for every locale throughout its extent.        
    texture The compactness of the marks that make up the symbol, also referred to as spacing.        
    texture The compactness of the marks that make up the symbol, also referred to as spacing.        
    thematic maps The family of maps that are about a particular topic or theme.        
    thematic maps The family of maps that are about a particular topic or theme.        
    third normal form The third stage in the normalization of a relational database in which all nonprimary keys are made mutually exclusive.        
    third normal form The third stage in the normalization of a relational database in which all nonprimary keys are made mutually exclusive.        
    TIGER/Line (Topologically Integrated Geographic Encoding and Referencing system) A vector file format developed by the US Census Bureau including map features such as census tracts, roads, railroads, buildings, rivers, and other features that support and improve the bureau’s ability to collect census information.        
    TIGER/Line (Topologically Integrated Geographic Encoding and Referencing system) A vector file format developed by the US Census Bureau including map features such as census tracts, roads, railroads, buildings, rivers, and other features that support and improve the bureau’s ability to collect census information.        
    TIN (Triangulated Irregular Network) A vector data structure that uses contiguous, nonoverlapping triangles to represent elevation.        
    TIN (Triangulated Irregular Network) A vector data structure that uses contiguous, nonoverlapping triangles to represent elevation.        
    Tint Colors produced by adding white to the original hue.        
    Tint Colors produced by adding white to the original hue.        
    title A map header that provides an overall descriptor of the map’s purpose.        
    title A map header that provides an overall descriptor of the map’s purpose.        
    Topology A set of rules that models the relationship between neighboring points, lines, and polygons and determines how they share geometry. Topology is also concerned with preserving spatial properties when the forms are bent, stretched, or placed under similar geometric transformation.        
    Topology A set of rules that models the relationship between neighboring points, lines, and polygons and determines how they share geometry. Topology is also concerned with preserving spatial properties when the forms are bent, stretched, or placed under similar geometric transformation.        
    union An overlay method that preserves all features, attribute information, and spatial extents from an input layer.        
    union An overlay method that preserves all features, attribute information, and spatial extents from an input layer.        
    USGS SDTS (Spatial Data Transfer Standard) DEM A distribution format for transferring USGS DEMs from one computer to another with zero data loss.        
    USGS SDTS (Spatial Data Transfer Standard) DEM A distribution format for transferring USGS DEMs from one computer to another with zero data loss.        
    Value The amount of white or black in the color.        
    Value The amount of white or black in the color.        
    Variable width buffers Regions of variable width around points, lines, or polygons.        
    Variable width buffers Regions of variable width around points, lines, or polygons.        
    variance A measure of the difference between a set of data points and their mean values.        
    variance A measure of the difference between a set of data points and their mean values.        
    vectorization The process of converting raster graphics to vector graphics.        
    vectorization The process of converting raster graphics to vector graphics.        
    vertex A corner or a point where lines meet.        
    vertex A corner or a point where lines meet.        
    Viewshed analysis The processing of determining the areas visible from a specific location.        
    Viewshed analysis The processing of determining the areas visible from a specific location.        
    watershed analyses The process of determining the direction of water flow over a desired area.        
    watershed analyses The process of determining the direction of water flow over a desired area.        
    world file A plaintext data file that specifies the locations and transformations of a feature dataset.        
    world file A plaintext data file that specifies the locations and transformations of a feature dataset.