Available Terms & Abbreviations

Geodesy

Term	Description
Geodesy	The Earth science of accurately measuring and understanding Earth's geometric shape, orientation in space and gravitational field. The field also incorporates studies of how these properties change over time and equivalent measurements for other planets (known as planetary geodesy).
Sphere	A geometrical object in three-dimensional space that is the surface of a ball. Defined mathematically as the set of points that are all at the same distance r from a given point in a three-dimensional space.
Ellipsoid	A surface that may be obtained from a sphere by deforming it by means of directional scalings, or more generally, of an affine transformation. In geodesy, a reference ellipsoid is a mathematically defined surface that approximates the geoid, which is the truer, imperfect figure of the Earth, or other planetary body, as opposed to a perfect, smooth, and unaltered sphere.
Spheroid	A quadric surface obtained by rotating an ellipse about one of its principal axes; in other words, an ellipsoid with two equal semi-diameters. A spheroid has circular symmetry. Geodesy represents the figure of the Earth as an oblate spheroid, which is an ellipsoid of revolution obtained by rotating an ellipse about its shorter axis. It is the regular geometric shape that most nearly approximates the shape of the Earth.
Geoid	Mathematical figure of the Earth, a smooth but irregular surface whose shape results from the uneven distribution of mass within and on the surface of Earth. It is the shape that the ocean surface would take under the influence of the gravity and rotation of Earth alone, if other influences such as winds and tides were absent.
WGS	The World Geodetic System is a standard for use in cartography, geodesy and satellite navigation including GPS. This standard includes the definition of the coordinate system's fundamental and derived constants, the ellipsoidal (normal) Earth Gravitational Model (EGM), a description of the associated World Magnetic Model (WMM), and a current list of local datum transformations. The latest revision is WGS 84 (also known as WGS 1984, EPSG:4326), established and maintained by the United States National Geospatial-Intelligence Agency since 1984, and last revised in 2014.
GCS	A Geographic Coordinate System is a coordinate system associated with positions on Earth (geographic position). These systems use the 3D model of the earth (ellipsoid) to define specific locations on the surface to create a grid. When we refer to locations using “longitude” (East/West measurement) and “latitude” (North/South measurement), we are using geographic coordinates.
Latitude	The "latitude" (lat) of a point on Earth's surface is the angle between the equatorial plane and the straight line that passes through that point and through (or close to) the center of the Earth (Y axis).
Longitude	The "latitude" (lat) of a point on Earth's surface is the angle between the equatorial plane and the straight line that passes through that point and through (or close to) the center of the Earth (Y axis).
Geodetic Datum	A coordinate system which is based on a specific ellipsoid and a set of reference points, used for locating places on the Earth. An approximate definition of sea level is the datum WGS 84, an ellipsoid, whereas a more accurate definition is Earth Gravitational Model 2008 (EGM2008), using at least 2,159 spherical harmonics. Other datums are defined for other areas or at other times.
EPSG	EPSG Geodetic Parameter Dataset is a public registry of geodetic datums, spatial reference systems, Earth ellipsoids, coordinate transformations and related units of measurement. Each entity is assigned an EPSG code between 1024-32767, along with a standard machine-readable well-known text (WKT) representation. The dataset is actively maintained by the IOGP Geomatics Committee.

Mapping

Term	Description
Cartography	The study and practice of making maps. Combining science, aesthetics, and technique, cartography builds on the premise that reality (or an imagined reality) can be modeled in ways that communicate spatial information effectively.
Map projection	A way to flatten a globe's surface (ellipsoid) into a plane in order to make a map. This requires a systematic transformation of the latitudes and longitudes of locations from the surface of the globe into locations on a plane.
SRS/CRS	A Spatial/Coordinate Reference System is a coordinate-based local, regional or global system used to locate geographical entities. A spatial reference system defines a specific map projection, as well as transformations between different spatial reference systems.
Projected Coordinate System	A projected coordinate system is a grid used as a reference for locations on the planet, but it’s a translation of the 3D grid onto a 2D plane (like a paper map or a computer screen).
Mercator projection	A cylindrical map projection presented by Flemish geographer and cartographer Gerardus Mercator in 1569. It became the standard map projection for navigation because it is unique in representing north as up and south as down everywhere while preserving local directions and shapes.
Web Mercator projection	(Google) Web Mercator / Spherical Mercator / Pseudo-Mercator, is a variant of the Mercator projection and is the de facto standard for Web mapping applications. It takes the WGS84 coordinate system and projects it onto a square. Web Mercator rose to prominence when Google Maps adopted it in 2005. It is used by virtually all major online map providers, including Google Maps, Mapbox, Bing Maps, OSM, Mapquest, ESRI, and many others. Its official EPSG identifier is EPSG:3857.
UTM	The Universal Transverse Mercator is a map projection system for assigning coordinates to locations on the surface of the Earth. Like the traditional method of latitude and longitude, it is a horizontal position representation, which means it ignores altitude and treats the earth as a perfect ellipsoid. However, it differs from global lat/long in that it divides earth into 60 zones and projects each to the plane as a basis for its coordinates. Specifying a location means specifying the zone and the x, y coordinate in that plane.
Photogrammetry	The science and technology of obtaining reliable information about physical objects and the environment through the process of recording, measuring and interpreting photographic images and patterns of electromagnetic radiant imagery and other phenomena.
Orthophoto	An aerial photograph or satellite imagery geometrically corrected ("orthorectified") such that the scale is uniform: the photo or image follows a given map projection. Unlike an uncorrected aerial photograph, an orthophoto can be used to measure true distances, because it is an accurate representation of the Earth's surface, having been adjusted for topographic relief, lens distortion, and camera tilt.
True Orthophoto	An orthophoto with a vertical view of the earth’s surface, eliminating building tilting and allowing a view of nearly any point on the ground.
Discrete Layer	A discrete layer represents a geographical region and is composed of multiple orthophoto mosaics (orthomosaics) with the same resolution, color scheme, and classification.
CE90, LE90, SE90	Imagery accuracy measurements: CE90 is the Circular Error at the 90th percentile. This means that a minimum of 90% of the points measured has a horizontal error less than the stated CE90 value. LE90 is the 90th percentile Linear Error, meaning that a minimum of 90% of vertical errors fall within the stated LE90 value. SE90 is the 90th percentile Spherical Error, meaning that a minimum of 90% of spatial errors fall within the stated SE90 value, which is a measure that combines the traditional LE90 and CE90 measures.

GIS

Term	Description
GIS	A Geographic Information System is a conceptualized framework that provides the ability to capture and analyze spatial and geographic data. GIS applications (or GIS apps) are computer-based tools that allow the user to create interactive queries (user-created searches), store and edit spatial and non-spatial data, analyze spatial information output, and visually share the results of these operations by presenting them as maps.
Raster data	Representation of a map, which made up as a matrix of pixels (bitmap), where each cell represent an area on the map with its color (aka imagery).
Vector data	Representation of entities in a map as basic geometries (made up of one or more interconnected vertices): points, lines, polygons, etc.
SDI	A Spatial Data Infrastructure implements a framework of geographic data, metadata, users and tools that are interactively connected in order to use spatial data in an efficient and flexible way.
Spatial database	A database that is optimized for storing and querying data that represents objects defined in a geometric space. Most spatial databases allow the representation of simple geometric objects such as points, lines and polygons.
Geospatial index	A spatial database index which allows to search records based on their geographic location in an efficient manner.
Quadtree index	A spatial indexing technique where each node represents a bounding box covering some part of the space being indexed, with the root node covering the entire area and each internal node has exactly four children.
R-Tree	A tree data structure used for spatial access methods, i.e., for indexing multi-dimensional information such as geographical coordinates, rectangles or polygons.
DEM	A Digital Elevation Model is a 3D computer graphics representation of elevation data to represent the surface of a planet (e.g. Earth), moon, or asteroid, above a certain datum. A "global DEM" refers to a discrete global grid.
DTM	The Digital Terrain Model represents the elevation of the bare earth without considering any over-ground features like plants and buildings.
DSM	The Digital Surface Model represents the elevation of the earth's surface that a remote sensing system will first meet (“blanket”). Thus, the resulting DSM includes the elevation of the bare earth terrain plus the natural (e.g., trees, shrubs) and man-made features (e.g., buildings, bridges).
TIN	A Triangulated Irregular Network is a representation of a continuous surface consisting entirely of triangular facets, used mainly as Discrete Global Grid in primary elevation modeling.
SRTM	The Shuttle Radar Topography Mission is an international research effort that obtained digital elevation models on a near-global scale from 56°S to 60°N (approximately 80% of the Earth's surface), to generate the most complete high-resolution digital topographic database of Earth, prior to the release of the ASTER GDEM in 2009.
ASTER GDEM	The Global Digital Elevation Model is a joint operation between NASA and Japan's Ministry of Economy, Trade and Industry (METI), the Global DEM is the most complete mapping of the earth ever made, covering 99% of its surface. The GDEM covers the planet from 83 degrees North to 83 degrees South, becoming the first earth mapping system that provide comprehensive coverage of the polar regions.
Tiled web map	A tiled web map, slippy map (OSM) or tile map (raster or vector) is a map displayed in a browser by seamlessly joining dozens of individually requested image or vector data files over the Internet. It is the most popular way to display and navigate maps, replacing other methods such as WMS which typically display a single large image, with arrow buttons to navigate to nearby areas.
LOD	Level of Detail refers to the complexity of a 3D model representation. LOD can be decreased as the model moves away from the viewer or according to other metrics such as object importance, viewpoint-relative speed or position.
Geoportal	A type of web portal used to find and access geographic information (geospatial information) and associated geographic services (display, editing, analysis, etc.) via the Internet. Geoportals are important for effective use of GIS and a key element of SDI.

Organizations And Companies

Term	Description
OGC	The Open Geospatial Consortium is an international voluntary consensus standards organization, originated in 1994. In the OGC, more than 500 commercial, governmental, nonprofit and research organizations worldwide collaborate in a consensus process encouraging development and implementation of open standards for geospatial content and services, sensor web and IoT, GIS data processing and data sharing.
OSGeo	The Open Source Geospatial Foundation is a not-for-profit organization whose mission is to support and promote the collaborative development of open source geospatial software, data and education. The foundation provides financial, organizational and legal support to the broader open source geospatial community.
ESRI	Environmental Systems Research Institute is an international supplier of GIS software, web GIS and geodatabase management applications.
MapBox	An American company which provides custom online maps for websites and applications. Mapbox is also the creator of, or a significant contributor to, some open source mapping libraries and applications, including the Mapbox GL-JS JavaScript library, the MBTiles specification, the TileMill cartography IDE, the Leaflet JavaScript library, and the CartoCSS map styling language and parser.

Standards

Term	Description
DTED	Digital Terrain Elevation Data is a standard of digital datasets which consists of a matrix of terrain elevation values, i.e., a DEM. Terrain elevations are described as the height above the Earth Gravitational Model 1996 (EGM96) geoid, not the WGS84 reference ellipsoid. The DTED format for level 0, 1 and 2 is described in U.S. Military Specification Digital Terrain Elevation Data (DTED).
GPKG	OGC GeoPackage is an open, non-proprietary, platform-independent and standards-based data format for geographic information system implemented as a SQLite database container. With the backing of the US military, GeoPackage has seen wide widespread support from various government, commercial, and open source organizations.
glTF	Graphics Language Transmission Format is a standard, JSON-based file format for 3D scenes and models. An open standard developed and maintained by the Khronos Group, it supports 3D model geometry, appearance, scene graph hierarchy and animation.
3D Tiles	OGC 3D Tiles is an open specification for sharing, visualizing, fusing, and interacting with massive heterogenous 3D geospatial content across desktop, web, and mobile applications. It is designed for streaming and rendering massive 3D geospatial content such as Photogrammetry, 3D Buildings, BIM/CAD, Instanced Features, and Point Clouds. It defines a hierarchical data structure and a set of tile formats which deliver renderable content.
CDB	OGC Common DB standard defines a standardized model and structure for a single, “versionable”, virtual representation of the earth. A CDB structured data store provides for a geospatial content and model definition repository that is plug-and-play interoperable between database authoring workstations.
GML	OGC Geography Markup Language is an XML grammar for expressing geographical features. GML serves as a modeling language for geographic systems as well as an open interchange format for geographic transactions on the Internet.
CityGML	An open standardised data model and exchange format to store digital 3D models of cities and landscapes. It defines ways to describe most of the common 3D features and objects found in cities (such as buildings, roads, rivers, bridges, vegetation and city furniture) and the relationships between them. It also defines different standard levels of detail (LoDs) for the 3D objects, which allows the representation of objects for different applications and purposes, such as simulations, urban data mining, facility management, and thematic inquiries.
GeoJSON	An open standard, JSON-based format designed for representing simple geographical features, along with their non-spatial attributes.
SLD	OGC Styled Layer Descriptor is an XML schema specified by for describing the appearance of map layers. It is capable of describing the rendering of vector and raster data.
KML	Keyhole Markup Language is an XML notation for expressing geographic annotation and visualization within 2D maps and 3D Earth browsers. KML was developed for use with Google Earth, which was originally named Keyhole Earth Viewer. KML became an international standard of OGC in 2008.
I3S	A single Indexed 3D Scene Layers data set, referred to as a Scene Layer, is a container for arbitrarily large amounts of heterogeneously distributed 3D geographic data (defined by OGC). Scene Layers are designed to be used in mobile, desktop, and server-based workflows and can be accessed over the web or as local files.
GeoTIFF	A public domain metadata standard which allows georeferencing information to be embedded within a TIFF file. The potential additional information includes map projection, coordinate systems, ellipsoids, datums, and everything else necessary to establish the exact spatial reference for the file.
COG	Cloud Optimized GeoTIFF is a regular GeoTIFF file, aimed at being hosted on a HTTP file server, with an internal organization that enables more efficient workflows on the cloud.
WPS	OGC Web Processing Service Interface Standard provides rules for standardizing inputs and outputs (requests and responses) for invoking geospatial processing services, such as polygon overlay, as a web service. The WPS standard defines how a client can request the execution of a process, and how the output from the process is handled.
OGC API	The OGC API family of standards are being developed to make it easy for anyone to provide geospatial data to the web. These standards build upon the legacy of the OGC Web Service standards (WMS, WFS, WCS, WPS, etc.), but define resource-centric APIs (REST) that take advantage of modern web development practices.

Protocols

Term	Description
WMS	OGC Web Map Service is a standard protocol for serving geo-referenced map images over the Internet. These images are typically produced by a map server from data provided by a GIS database.
WMTS	OGC Web Map Tile Service is a standard protocol for serving pre-rendered or run-time computed geo-referenced map tiles over the Internet.
TMS	Tile Map Service or is an older specification for tiled web maps, developed by OSGeo.
WFS	OGC Web Feature Service Interface Standard provides an interface allowing requests for geographical features across the web using platform-independent calls.
WCS	OGC Web Coverage Service Interface Standard defines Web-based retrieval of coverages – that is, digital geospatial information representing space/time-varying phenomena.
CSW	OGC catalog Services for the Web, a standard for exposing a catalog of geospatial records in XML on the Internet (over HTTP).
XYZ	The de-facto OpenStreetMap standard, known as Slippy Map Tilenames or ZXY, where Z is the zoom level, and X and Y identify the tile.

Technologies

Term	Description
GPS	The Global Positioning System is a satellite-based radio navigation system owned by the United States government and operated by the United States Space Force. It is one of the global navigation satellite systems (GNSS) that provides geolocation and time information to a GPS receiver anywhere on or near the Earth where there is an unobstructed line of sight to four or more GPS satellites.
OSM	OpenStreetMap is a collaborative project to create a free editable map of the world. The geodata underlying the map is considered the primary output of the project. The creation and growth of OSM has been motivated by restrictions on use or availability of map data across much of the world, and the advent of inexpensive portable satellite navigation devices.
GEE	Google Earth Enterprise is a geospatial application which provides the ability to build and host custom 3D globes and 2D maps.
OpenLayers	An open-source JavaScript library for displaying map data in web browsers as slippy maps. It provides an API for building rich web-based geographic applications similar to Google Maps and Bing Maps.
OSG	OpenSceneGraph is an open-source 3D graphics API used by application developers in fields such as visual simulation, computer games, virtual reality, scientific visualization and modeling.
GDAL	The Geospatial Data Abstraction Library is a computer software library from the Open Source Geospatial Foundation, for reading and writing raster and vector geospatial data formats. As a library, it presents a single abstract data model to the calling application for all supported formats.
GeoServer	An open-source server that allows users to share, process and edit geospatial data. Designed for interoperability, it publishes data from any major spatial data source using open standards.
MapProxy	An open-source proxy for geospatial data. It caches, accelerates and transforms data from existing map services and serves any desktop or web GIS client.
Cesium	A complete platform for 3D geospatial data – handling everything from optimization to visualization to analytics. CesiumJS is an open source JavaScript library for world-class 3D mapping.
GDB	ArcGIS geodatabase is a collection of geographic datasets of various types held in a common file system folder, a Microsoft Access database, or a multiuser RDBMS (e.g. Oracle, Postgres, etc.)
BIL, BIP, BSQ	Band interleaved by line, Band interleaved by pixel and Band Sequential are three common methods of organizing image data for multiband images. BIL, BIP, and BSQ are not in themselves image formats but are schemes for storing the actual pixel values of an image in a file. These files support the display of single and multiband images and handle black-and-white, grayscale, pseudo color, true color, and multispectral image data.
Leaflet	An open source JavaScript library used to build web mapping applications. First released in 2011, it supports most mobile and desktop platforms, supporting HTML5 and CSS3.