Glossary of Terms - G

gateway service
The Open Location Services (OLS) initiative introduced gateway services, which link location application services (accessed via the Internet or the Web) with mobile wireless-IP platforms, in support of small form factor mobile terminals.
A catalogue of toponyms (place names) assigned with geographic references. A gazetteer service retrieves the geometries for one or more features, given their associated well-known feature identifiers (text strings).
gazetteer model
The general model for representing online, well-known types of gazetteers.
general feature model
Metamodel of feature types. A feature may have properties that may be operations, attributes or associations. Any feature may have a number of attributes, some of which may be geometric and spatial. A feature is not defined in terms of a single geometry, but rather as a conceptually meaningful object within a particular domain of discourse, one or more of whose properties may be geometric.
general models
Source: The OpenGIS® Abstract Specification Topic 6: The Coverage Type and its Subtypes Version 6.
General Models Define the basic models for how geospatial information is to be characterized and encoded. To date, OGC has defined several types of General Models: (Simple) Feature Model, Coverage Model, Observation Model, Registry Model, Service Model, Data Catalog Model, Dictionary Model, Directory Model, and Gazetteer Model.
Transforms a description of a feature location, such as a place name, street address or postal code, into a normalized description of the location, which includes a coordinate geometry.
geocoder Service
Geocoding is the process of linking words, terms and codes found in a text string to their applicable geospatial features, with known positions (i.e., usually a point with x, y coordinates but more generally any geometry), e.g. converting a street address to a geographic location. The Geocoder Service Interface allows for a request providing an address or set of addresses and returns them along with the corresponding geometry (usually a point relative to a requested spatial reference system.) The request is "sent" to a Geocoder Service, which processes the request and returns the resulting geographic feature representing position.
Geocoding refers to the assignment of alphanumeric codes or coordinates to geographically reference data provided in a textual format. Examples are the two letter country codes and coordinates computed from addresses.
Digital data that represent the geographical location and characteristics of natural or man-made features, phenomena and boundaries of the Earth. Geodata represent abstractions of real-world entities, such as roads, buildings, vehicles, lakes, forests and countries. Geodata refers to such data in any format, including raster, vector, point, text, video, database records, etc.
geographic application
Applications which pertain to the Earth and Earth phenomena, with known spatial and temporal reference systems. Expressed in a human context versus computer context.
geographic data
See geospatial data.
geographic feature
Feature associated with a location relative to the Earth. The starting point for modeling of geographic information. A feature is an abstraction of a real world phenomenon. A geographic feature is a feature associated with a location relative to the Earth. A digital representation of the real world can be thought of as a set of features. Geographic features occur at two levels: feature instances and feature types. At the instance level, a geographic feature is represented as a discrete phenomenon that is associated with its geographic and temporal coordinates. These individual feature instances are grouped into classes with common characteristics - feature types.
geographic model
A model of the real world that recognizes an integrated family of spatial features
Geographic Objects
The vision for the Geographic Objects Initiative is to define platform-independent and implementation-neutral interface models of specific geographic services or component objects.
geographic reference system
A 3D reference coordinate system with well-defined origin and orientation of the coordinate axes. A mathematical system.
Geography Markup Language (GML)
OGC`s XML-based language for describing and encoding geospatial information. An application of XML, a specification developed by members of the Open GIS Consortium. ". GML is an XML encoding for spatial data. In a sense, it is a schema-writing language for spatial information.
geometric object
A combination of a coordinate geometry and a coordinate reference system. In general, a geometric object is a set of geometric points.
GeoMobility Server
The open service platform comprising the Core Services developed under the OGC OpenLS initiatives.
geoparser service
Geoparsing refers to the capability to process a textual document and identify key words and phrases that have a spatial context. A Geoparsing Interface implementing this specification works in the context of two bodies of information: a reserved vocabulary (usually of place names, such as a gazetteer) and a text source (e.g., a newspaper, or voice track.) The Geoparser Service returns all occurrences of the use (in the text source) of any word in the reserved vocabulary. Each occasion establishes a geolink between the source and the location associated with the reserved word.
Use of computers to acquire, analyze, store, display, and distribute information about geographic features. This includes GIS and systems for remote sensing (Earth imaging), facilities management, automated mapping, cartography, navigation, and location services.
geoprocessing applications
Computer applications which model, interpret and use Earth information. The implementation of a Geographic Application on a computer. The terms `geoprocessing,` `geomatics,` and `geotechnology` mean approximately the same thing, though some groups make minor distinctions among them.
georectified gridded data
A cell in a georectified gridded data can be uniquely geolocated, given the cell spacing, grid origin and orientation. Ungeorectified gridded data are irregularly spaced in any geographic/map projection coordinate system. Therefore, the location of one cell in an ungeorectified gridded data cannot be determined based on another cell's location. One approach to rectifying imagery utilizes a sensor description.
Source: PreANVIL Glossary
Description of a location relative to the Earth
Referring to location relative to the Earth's surface. "Geospatial" is more precise in many GI contexts than "geographic," because geospatial information is often used in ways that do not involve a graphic representation, or map, of the information.
geospatial data
Location properties related to any terrestrial feature or phenomena. Location properties may include any information about the location or area of, and relationships among, and descriptive information about geographic features and phenomena. This includes remotely sensed data, vector map data, addresses, coordinates, etc. Note that "geospatial data" is more precise in many contexts than "geographic data," because geospatial data is often used in ways that do not involve a graphic representation, or map, created from the data.
Geospatial Fusion Services
Source: PreANVIL Glossary
Non-map information - text, video, audio, digital photographs, mpeg movies, sensor data, word processing documents, etc. - often refers to place. Geospatial Fusion Services enable the "fusing" of information such as addresses, place names, coordinates, pinpoints on photographs, and descriptive directions into one information management framework that supports search, discovery, and sharing of spatial information stored in non-map formats.
geospatial information
Information about entities and phenomena that includes their location with respect to the Earth`s surface. Frequently used as a synonym to geodata, but technically, geodata are "dry" digitally represented facts or recorded observations which on their own have no meaning. They become information when interpreted and put in context by humans.
geospatial portal
A Web site that provides a view into a universe of spatial content and activity through a variety of links to other sites, communication and collaboration tools, and special features geared toward the community served by the portal. As an open Web resource, a geospatial portal should connect through open interfaces to data and services with similar interfaces. Catalogs and registries that conform to OpenGIS Specifications play an important role in geospatial portals.
Data interchange standard for raster geographic images. An extension of the TIFF format to support a geodetically sound raster data georeferencing capability. The aim of GeoTIFF is to allow a means for tying a raster image to a known model space or map projection, and for describing those projections. The geographic content supported in GeoTIFF tag structure includes its cartographic projection, datum, ground pixel dimension, and other geographic variables.
GFS Testbed
OGC`s GFS Testbed yielded a set of candidate standard specifications for open interfaces and protocols that begin to support "geospatial fusion."
Graphic Interchange Format An image format commonly used on the Web
National Information Infrastructure. The world`s entire collection of public and private digital information, physical networks and network software, computers, and knowledge about how to use them.
Source: AGI glossary.
"Geographic Information System. A computer system for capturing, storing, checking, integrating, manipulating, analyzing and displaying data related to positions on the Earth`s surface. " Both vector and raster GISs are available.
GIS application
Source: OpenGIS Guide
"The use of capabilities, including hardware, software and data, provided by a Geographic Information System specific to the satisfaction of a set of user requirements. Example of a GIS application: Spatial decision support system application for district planning purposes."
The Geospatial Information for Sustainable Development Initial Capability Pilot (GISD-ICP) is the first of a series of projects to help make geographic information more accessible and useful to decision makers working on sustainable development problems.
Global Spatial Data Infrastructure (GSDI)
A set of policies, standards, practices, technologies, and relationships to facilitate the flow of geographic data and information at all levels across government, academic, and private sectors globally. A linking of National Spatial Data Infrastructures. See
Source: Wikipedia
A globe is a three-dimensional scale model of Earth (terrestrial globe or geographical globe) or other celestial body such as a planet or moon. While models can be made of objects with arbitrary or irregular shapes, the term globe is used only for models of objects that are approximately spherical.
Source: PreANVIL Glossary
"Geographic Mark-up Language: an application of XML, a specification developed by members of the Open GIS Consortium. ". GML is an XML encoding for spatial data. In a sense, it is a schema-writing language for spatial information.
GML Application Schema
An XML Schema written according to the GML 3 rules for Application Schemas, which defines a vocabulary of geographic objects for a particular domain of discourse
Source: PreANVIL Glossary
Global Positioning System: (1) a network of satellites that interact with special receivers to position the receiver relative to the Earth. (2) describing the generic approach to using a network of satellites to deliver a positioning service. Although GPS can be used to determine location very precisely (within centimeters given the correct controls and proper use, it does not solve all the problems of location determination in GIS databases.

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