Guidance
Geospatial Glossary
Updated 11 March 2021
© Crown copyright 2021
This publication is licensed under the terms of the Open Government Licence v3.0 except where otherwise stated. To view this licence, visit nationalarchives.gov.uk/doc/open-government-licence/version/3 or write to the Information Policy Team, The National Archives, Kew, London TW9 4DU, or email: psi@nationalarchives.gov.uk.
Where we have identified any third party copyright information you will need to obtain permission from the copyright holders concerned.
This publication is available at https://www.gov.uk/government/publications/geospatial-glossary/geospatial-glossary
A
| 0D model | A point has no dimension (0D) as there is no inside | Source: W3C |
| 1D model | A line has a dimension of one (1D) because only one coordinate is needed to specify a point along it – for example, the point at 5 on a number line. | Source: W3C |
| 2D model | A surface such as a plane or the surface of a sphere has a dimension of two (2D) because two coordinates are needed to specify a point on it – for example, both a latitude (y-coordinate) and longitude (x-coordinate) are required to locate a point on the surface of a sphere. | Source: W3C |
| 3D model | The inside of a sphere is three-dimensional (3D) because three coordinates (x, y and z) are needed to locate a point within these spaces. | Source: W3C |
| 4D model | 4D model fuses the three dimensions of space (see 3D model) and the one dimension of time into a single four-dimensional continuum. (spacetime) | Source: Wikipedia |
| Absolute accuracy | Closeness of reported values to values accepted as or being true. | Source: ISO |
| Absolute coordinates | A coordinate pair or triplet measured directly from the origin of the coordinate system in which it lies and not to any other point in the system. | Source: W3C |
| Absolute positional accuracy | The closeness of reported coordinate values to values accepted as or being true. | Source: OS |
| Acceptable use policy (AUP) | A policy that establishes an agreement between users and the organisation and defines for all parties the ranges of use that are approved before gaining access to a network or the Internet. | Source:OS |
| Address | Structured information that allows the unambiguous determination of an object for purposes of identification and location. | Source: ISO |
| Addressable object | Spatial object type which can have instances to which it is meaningful to associate addresses. | Source: INSPIRE |
| Administrative area | A blanket term used to refer to all public administrative areas, specifically local government management and electoral areas. | Source: OS |
| Administrative unit | A single administrative area. | Source: OS |
| Aggregation | A process that transforms atomic data into aggregate-level information by using an aggregation function such as count, sum, average, standard deviation, etc. | Source: DAMA |
| Airspace | The owner of land is assumed to own the airspace above it as far as is required for ordinary use and enjoyment of land, but cannot prevent aircraft flying over at a reasonable height (s.76(1), Civil Aviation Act 1982). | Source: HMLR |
| Altitude | Distance of a point from a chosen reference surface along a line perpendicular to that surface (often height above sea level). | Source: W3C |
| Area | A particular part of a place, piece of land, or country; a part of the earth’s surface of land or water. | Source: Cambridge English Dictionary |
| Area of interest | A user defined area (represented by a bounding box, circle or polygon). Often used as a filter in a query. | Source: OGC |
| Association for Geographic Information (AGI) | The AGI is an independently-funded and impartial organisation which aims to educate and support all existing and new practitioners and participants in the industry, in order to maximize the benefits delivered by GI, and to develop awareness of its potential. | Source: AGI |
| Atomic data | Data at the lowest chosen level of detail (granularity). The level of detail chosen depends on the information requirements of the enterprise. For example, address could be one atomic item, or address could be split into further composite items such as house identifier and city. Opposite of aggregate data. | Source: DAMA |
| Attribute | Named property of an entity. Descriptive information about features or elements of a database. For a database feature like census tract, attributes might include many demographic facts including total population, average income, and age. In statistical parlance, an attribute is a variable, whereas the database feature represents an observation of the variable. | Source: ISO / OGC |
| Authoritative Data | Officially recognised data of appropriate quality provided by trustworthy organisations | Source: GOV.UK |
| Authoritative Source | A source of data or information that is recognised by members of a community of interest to be valid or trusted because its provenance is considered highly reliable or accurate. During the life cycle process, the authoritative source (or system of use in which it is housed) can evolve according to use. Subject matter experts validate that the data is authoritative, and data management assures that data from the authoritative source is provided to users, and that it is current. | Source: DAMA |
| Axis | In a coordinate system, the coordinates specify each point uniquely in a plane, which are the signed distances to the point from two fixed perpendicular oriented lines. Each reference line is called a coordinate axis or just axis (plural axes) of the system. | Source: Wikipedia |
| Axis order | The order in which coordinates are presented. For example, some systems use (latitude, longitude) rather than (longitude, latitude). The latter is more similar to the mathematical convention of (x, y) ordering. The order used may differ from the order used to define the coordinate system. | Source: W3C |
B
| Band | Range of wavelengths of electromagnetic radiation that produce a single response by a sensing device. | Source: ISO |
| Base maps | Spatial data sets that provide the background upon which more specific thematic data is overlaid and analyzed. As inputs into a GIS, the term base map is usually applied to those sources of information about relatively permanent features including topography, soil data, geology, cadastral divisions, and political divisions. Within a GIS database, such information may become part of a land base to which other information is indexed and referenced. | Source: OGC |
| Bathymetry | Bathymetry is the study of underwater depth of lake or ocean floors. In other words, bathymetry is the underwater equivalent to topography. | Source: Wikipedia |
| Bearing | Horizontal angle at a point relative to a specified direction. | Source: ISO |
| Bounding box | Coordinates of a box within which all spatial entities are contained. | Source: ONS |
| British Geological Survey (BGS) | The BGS is one of the centres that makes up the Natural Environment Research Council. It is active in areas such as land-use planning, waste disposal, decarbonisation, civil engineering, minerals extraction, contaminated land, seismic and geohazard evaluation and understanding climate change. | Source: BGS |
| British National Grid | A unique referencing system that can be applied to all Ordnance Survey maps of Great Britain (GB) at all scales. It is used by Ordnance Survey on all post war mapping to provide an unambiguous spatial reference in Great Britain for any place or entity whatever the map scale. The National Grid is defined by the OSGB36 spheroid. | Source: OS |
| British Standards Institute | The UK authority for international and domestic standards promulgation. | Source: OS |
| Buffer | A buffer tool is a proximity function that creates a polygon at a set distance surrounding a selected feature or features. Therefore, a buffer is a zone around a map feature measured in units of distance or time. | Source: OS |
C
| Cadastral parcel (CP) | A single area of the earth’s surface under homogenous real property rights and unique ownership, real property rights and unique ownership being defined by national laws | Source:HMLR | |
| Cadastre | A cadastre (also spelled cadaster) is a comprehensive land recording of the real estate or real property’s metes-and-bounds of a country. | Source: Wikipedia | |
| Cartesian coordinate system | A coordinate system that specifies each point uniquely in a plane by a set of numerical coordinates, which are the signed distances to the point from two fixed perpendicular oriented lines, measured in the same unit of length. | Source:Wikipedia | |
| Cartogram map | A cartogram is a map in which some thematic mapping variable – such as travel time, population, or GNP – is substituted for land area or distance. The geometry or space of the map is distorted, sometimes extremely, in order to convey the information of this alternate variable. | Source: Wikipedia | |
| Cartography | Cartography is the study and practice of making maps | Source: Wikipedia | |
| Centroid | The term given to the center of an area, region, or polygon. | Source: OGC | |
| Choropleth map | A choropleth map is a type of thematic map in which areas are shaded or patterned in proportion to a statistical variable that represents an aggregate summary of a geographic characteristic within each area, such as population density or per-capita income. | Source: Wikipedia | |
| Coal Authority (The) (TCA) | The Coal Authority works to resolve the impacts of mining.The Coal Authority is an executive non-departmental public body, sponsored by the Department for Business, Energy & Industrial Strategy. | Source:TCA | |
| Comma separated values (CSV) | A file format for tabular data that writes each row on a separate line and each cell is separated from the next with a comma. CSV is just one variety of tabular data. | Source: W3C | |
| Composite map | Two or more maps with the same geographic extent and coordinate reference system can be accurately layered to produce a composite map. | Source: OGC | |
| Connectivity | A topological property relating to how geographical features are attached to one another functionally, spatially, or logically. In a water distribution system, connectivity would refer to the way pipes, valves, and reservoirs are attached, implying that water could be traced from its source in the network, from connection to connection, to any given final point. Functional, spatial, and logical connectivity are examples of relationships that can be represented and analyzed in a GIS database. | Source: OGC | |
| Contour | A line connecting points of equal value. | Source:OS | |
| Conversion | Transformation from one format to another e.g. raster to vector | Source:ISO | |
| Coordinate | One of a sequence of n-numbers designating the position of a point in n-dimensional space. | Source: ISO | |
| Coordinate reference system (CRS) | Coordinate reference system is a coordinate-based local, regional or global system used to locate geographical entities. | Source: ONS |
D
| Data | Discrete values and statistics collected together for reference or analysis. These values can be represented as text, numbers, graphics, images, sound, or video. | Source: OS |
| Data lifecycle | The data life cycle is the sequence of stages that a particular unit of data goes through from its initial generation or capture to its eventual archival and/or deletion at the end of its useful life. | Source: whatis.com |
| Data Lineage | Data lineage includes the data origin, what happens to it and where it moves over time. | Source: Wikipedia |
| The Data Management Association (DAMA) | DAMA is a global community of Data Management Professionals organised around local membership based chapters. The chapters are supported by DAMA-International who maintain the Data Management Body of Knowledge (DMBoK) and the Certified Data Management Professional (CDMP) certification.DAMA’s primary purpose is to promote the understanding, development and practice of managing data and information as key enterprise assets to support the organisation. | Source: DAMA |
| Data quality | Data quality refers to the state of qualitative or quantitative pieces of information. There are many definitions of data quality but data is generally considered high quality if it is “fit for [its] intended uses in operations, decision making and planning” | Source: Wikipedia |
| Dataset | Identifiable collection of data. | Source: ISO |
| Datum | Parameter or set of parameters that define the position of the origin, the scale, and the orientation of a coordinate system. | Source:ISO |
| Depth | Distance of a point from a chosen reference surface measured downward along a line perpendicular to that surface. | Source: ISO |
| Digital elevation model (DEM) | Digital representation of earth’s surface. | Source:ISO |
| Digital surface model (DSM) | Digital elevation model (DEM) that depicts the elevations of the top surfaces of buildings, trees, towers, and other features elevated above the bare earth | Source: ISO |
| Digital terrain model (DTM) | Digital elevation model (DEM) that incorporates the elevation of important topographic features on the land. | Source: ISO |
| Digitise | The process of converting information into the digital codes stored and processed by computers. In geographic applications, digitizing usually means tracing map features into a computer using a digitizing tablet, graphics tablet, mouse, or keyboard cursor. | Source:OGC |
| Dimension | In physics and mathematics, the dimension of a mathematical space (or object) is informally defined as the minimum number of coordinates needed to specify any point within it. See 0D model, 1D model, 2D model, 3D model and 4D model. | Source: W3C |
| Discrete global grid system (DGGS) | A DGGS is a spatial reference system that uses a hierarchical tessellation of cells to partition and address the globe. DGGS are characterized by the properties of their cell structure, geo-encoding, quantization strategy and associated mathematical functions. | Source:OGC |
| Discrete spatiotemporal object | Temporal sequence of object representations depicting the same spatial feature at different times | Source: ISO |
| Dublin core | A standard core ontology for meta-data about documents, originating in Dublin Ohio and managed by the Dublin Core Metadata Initiative. | Source: DAMA |
E
| Easting | Distance in a coordinate system, eastwards (positive) or westwards (negative) from a north-south reference line | Source: ISO (pdf, 1.44 MB) |
| Entity | Any concrete or abstract thing that exists, did exist, or might exist, including associations among these things e.g. a person, object, event, idea, process, etc. | Source: DAMA |
| ETRS89/EVRS | ETRS89/EVRS is a compound coordinate reference system used for unambiguous 3D georeferencing in Europe area | Source:INSPIRE |
| European terrestrial reference system 1989(ETRS89) | European Terrestrial Reference System 1989 (ETRS89) is used as the horizontal component of ETRS89/EVRS | Source:INSPIRE |
| European vertical reference system (EVRS) | European Vertical Reference System (EVRS) is used as the vertical component of ETRS89/EVRS. | Source: INSPIRE |
| Extent | The area covered by something. | Source: W3C |
F
| Feature | A feature is an object that can have a geographic location and other properties. | Source:UKHO |
| Feature Type | Features that share membership of a common theme | Source:UKHO |
| Field | A data field is a place where you can store data. Commonly used to refer to a column in a database or a field in a data entry form or web form. The field may contain data to be entered as well as data to be displayed. | Source:UKHO |
G
| Gazetteer | Register of location instances of one or more location sub-types, containing some information regarding position. | Source: OGC |
| GEo-spatial Metadata INteroperability Initiative (UK GEMINI) | UK GEMINI (GEo-spatial Metadata INteroperability Initiative) is a specification for a set of metadata elements for describing geospatial data resources. | Source: AGI |
| Geocode | To transform 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. | Source: OGC |
| Geodata | 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. | Source: OGC |
| Geodesy | Geodesy is the Earth science of accurately measuring and understanding Earth’s geometric shape, orientation in space and gravitational field | Source: Wikipedia |
| Geodetic | Geodetic is an adjective meaning pertaining to geodesy, the science of measurement of the earth | Source: Wikipedia |
| Geographic coordinates | Longitude, latitude and height of a ground or elevated point | Source:ISO |
| Geographic information system (GIS) | Geographic Information Systems (GIS) provides accurate information, assistance, support, and maintains and creates information to aid in the development of maps and data analysis. | Source: Wikipedia |
| Geography markup language (GML) | The Geography Markup Language (GML) 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. | Source: OGC |
| Geoid | The geoid 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. | Source:Wikipedia |
| GeoJSON | GeoJSON is an open standard format designed for representing simple geographical features, along with their non-spatial attributes. It is based on JSON, the JavaScript Object Notation. It can represent points, lines and polygons. It is documented in IETF standard 7946 | Source: GeoJSON |
| Geolocation | Geolocation is the identification or estimation of the real-world geographic location of an object. In its simplest form, geolocation involves the generation of a set of geographic coordinates and is closely related to the use of positioning systems, but its usefulness is enhanced by the use of these coordinates to determine a meaningful location, such as a street address. | Source: Wikipedia |
| Geology | The study or science of the earth, its history, and its life as recorded in the rocks; includes the study of geologic features of an area, such as the geometry of rock formations, weathering and erosion, and sedimentation. | Source:GEMET |
| Geomatics | The discipline concerned with the collection, distribution, storage, analysis, processing, presentation of geographic data or geographic information | Source:ISO |
| Geometry | An ordered set of n-dimensional points in a given coordinate reference system; can be used to model the spatial extent or shape of a Spatial Thing. | Source: W3C |
| Geoparse | Geoparsing is the process of converting free-text descriptions of places (such as “twenty miles northeast of Jalalabad”) into unambiguous geographic identifiers, such as geographic coordinates expressed as latitude-longitude. One can also geoparse location references from other forms of media, for example audio content in which a speaker mentions a place. With geographic coordinates the features can be mapped and entered into Geographic Information Systems. | Source: Wikipedia |
| Geophysics | Geophysics is a subject of natural science concerned with the physical processes and physical properties of the Earth and its surrounding space environment, and the use of quantitative methods for their analysis. | Source: Wikipedia |
| Geoprocessing | Geoprocessing is a framework and set of tools for processing geographic and related data. The comprehensive suite of geoprocessing tools can be used to perform spatial analysis or manage GIS data in an automated way. | Source: Wikipedia |
| Georectify | To correct positional displacement with respect to the surface of the Earth | Source: ISO |
| Georeference | To position an object from a set of points for which both ground and image coordinates are known | Source:Wikipedia |
| Geospatial | The word geospatial is used to indicate that data that has a geographic component to it. This means that the records in a dataset have locational information tied to them such as geographic data in the form of coordinates, address, city, or postcode. | Source: Wikipedia |
| Geospatial Commission | The Geospatial Commission is an expert committee that will set the UK’s geospatial strategy and promote the best use of geospatial data.The Geospatial Commission is part of the Cabinet Office. | Source: gov.uk |
| Global positioning system (GPS) | The United States’ Global Navigation Satellite System (GNSS) interacts with special receivers to position the receiver relative to the Earth. | Source:ISO |
| Government Geography Profession | The Government Geography Profession supports effective use of geospatial skills and geographic principles in analyses and policy making. The profession is part of the Government Analysis Function and has established the following roles: Geographic Analysts, Geographic Advisors, Geospatial Information Specialists, Multidisciplinary Geographers, Affiliate Geographers. | Source:gov.uk |
| Grid coordinate system | Coordinate system in which a position is specified relative to the intersection of curves | Source: ISO |
| Gridded data | Data whose attribute values are associated with positions on a grid coordinate system | Source:ISO |
| Ground control point | Point on the earth that has an accurately known geographic position | Source:ISO |
H
| Her Majesty’s Land Registry (HMLR) | Her Majesty’s Land Registry is a non-ministerial department of the Government of the United Kingdom, created in 1862 to register the ownership of land and property in England and Wales. | Source: HMLR |
| Her Majesty’s Nautical Almanac Office | Her Majesty’s Nautical Almanac Office produces astronomical data and is part of the United Kingdom Hydrographic Office | Source: UKHO |
| Horizontal datum | Horizontal datums are a series of data points on the surface of the earth that are used to measure the position of oneself on the Earth’s surface. | Source: UKHO |
| Hydrography | (1)Hydrography is a term describing the geographic representation of water features such as streams, rivers and lakes in a GIS; or (2) Hydrography involves measuring the depth of the water and fixing the position of all the navigational hazards that lie on the seafloor, such as wrecks and rocks. | Source:(1) GIS Dictionary (2) UKHO |
| Hydrography | 1) Of or relating to the characteristic features (such as flow or depth) of bodies of water, or(2)relating to the charting of bodies of water. | Source:Merriam Webster Dictionary |
I
| Index map | The display of index polygons against the current Ordnance Survey map to provide an index of all registered titles and pending applications for first registration. | HMLR |
| Infrastructure for spatial information | Means metadata, spatial data sets and spatial data services; network services and technologies; agreements on sharing, access and use; and coordination and monitoring mechanisms, processes and procedures, established, operated or made available in accordance with this Directive (INSPIRE) | Source: INSPIRE |
| Infrastructure for Spatial Data in Europe (INSPIRE) | Infrastructure for Spatial Data in Europe. An EU initiative to establish an infrastructure that will help to make spatial or geographical information more accessible and interoperable for a wide range of purposes supporting sustainable development. See http://inspire.jrc.ec.europa.eu/. | Source:EC |
| International Organization for Standardization (ISO) | ISO is an independent, non-governmental international organization with a membership of 164 national standards bodies.Through its members, it brings together experts to share knowledge and develop voluntary, consensus-based, market relevant International Standards that support innovation and provide solutions to global challenges. | Source: ISO |
J
| Junction | Single topological node in a network with its associated collection of turns, incoming and outgoing links | Source: ISO |
L
| Land administration | Process of determining, recording and disseminating information about the relationship between people and land | Source:ISO |
| Land cover | Land cover is the physical state of the land surface. It is the combination of vegetation, soil, rock, water and human-made structures, which make up the earth’s landscape. The land cover is the interface between the earth’s crust and the atmosphere, influencing the exchange of energy and matter in the climatic system and biogeochemical cycles. | Source: GEMET |
| Land Registry Property Gazetteer | An address database that links title registrations to an address. | Source: data.gov.uk |
| Land | The solid surface of Earth that is not permanently covered by water. | Source: Wikipedia |
| Land Registry | See “Her Majesty’s Land Registry” | |
| Latitude | The angular distance north or south of the equator. Often abbreviated to Lat. | Source: W3C |
| Layer | Basic unit of geographic information that may be requested as a map from a server | Source: ISO |
| Legend | A visual explanation of the symbols used on the map also called a key. | Source: GIS Wiki |
| LIght Detection And Ranging (LIDAR) | System consisting of 1) a photon source (frequently, but not necessarily, a laser), 2) a photon detection system, 3) a timing circuit, and 4) optics for both the source and the receiver that uses emitted laser light to measure ranges to and/or properties of solid objects, gases, or particulates in the atmosphere | Source:ISO |
| Linked geodata | Geographic data and information sources published on the Semantic Web | Source: ISO |
| Longitude | The angular distance east or west of the prime meridian. Often abbreviated to Long. | Source: W3C |
M
| Map | A two-dimensional visual portrayal of geospatial data. A map is not the data itself. | Source: OGC |
| Map projection | Coordinate conversion from an ellipsoidal coordinate system to a plane | Source: ISO |
| Map scale | The ratio between the extent of a feature on the map and its extent on the ground, normally expressed as a representative fraction, such as 1:1250 or 1:10 000. | Source: OS |
| Marine Environmental Data and Information Network (MEDIN) | A partnership of UK organisations committed to improving access to UK marine data | Source: UKHO |
| Meridian | Intersection of an ellipsoid by a plane containing the shortest axis of the ellipsoid | Source: ISO |
| Metadata | Data about data or a service. Metadata is the documentation of data. In human-readable form, it has primarily been used as information to enable the manager or user to understand, compare and interchange the content of the described data set. In the Web Services context, XML-encoded (machine-readable and human-readable) metadata stored in catalogs and registries enables services to use those catalogs and registries to find data and services. | Source:OGC |
| Metadata schema | Conceptual schema describing metadata Note: ISO 19115 describes a standard for metadata schema. | Source:ISO |
N
| National mapping agencies | National government agencies, such as Great Britain’s Ordnance Survey, Ordnance Survey of Northern Ireland, France`s Institut Geographique National (IGN) and the United States US Geological Survey and Federal Geographic Data Committee, that are chartered to provide national mapping products and services. | Source: OGC |
| National spatial data infrastructure | The National Spatial Data Infrastructure (NSDI) is described as “the technology, policies, standards, and human resources necessary to acquire, process, store, distribute, and improve utilization of geospatial data” | Source:Oxford Dictionary |
| Nautical Chart | A graphic representation of a sea area and adjacent coastal regions. | Source: Wikipedia |
| Neighbourhood | Geometric set containing a specified direct position in its interior, and containing all direct positions within a specified distance of the specified direct position | Source: ISO |
| Node | A node is an important point along a line feature where two lines intersect | Source: gisgeography.com |
| Northing | Northing and easting are geographic Cartesian coordinates for a point. Easting is the eastward-measured distance and northing is the northward-measured distance. | Source:Wikipedia |
O
| Open data | Open data is data that’s available to everyone to access, use and share. | Source: Environment Agency |
| Open Data Institute (ODI) | An independent, non-profit, non-partisan company that works with companies and governments to build an open, trustworthy data ecosystem. | Source: ODI |
| Open Geospatial Consortium (OGC) | An international consortium of more than 500 businesses, government agencies, research organisations, and universities driven to make geospatial (location) information and services FAIR - Findable, Accessible, Interoperable, and Reusable. . | Source: OGC |
| Open Government Licence (OGL) | The Open Government Licence is a copyright licence for Crown Copyright works published by the UK government. Other UK public sector bodies may apply it to their publications. The OGL permits anyone to copy, publish, distribute, transmit and adapt the licensed work, and to exploit it both commercially and non-commercially. In return, the re-user of the licensed work has to acknowledge the source of the work and (if possible) provide a link to the OGL. | Source: Wikipedia |
| Open specification | A specification that promotes interoperability through its public availability to developers, who use it to develop software or hardware compatible with the common resource described in the specification. Open specifications are generally consistent with related standards and are updated to conform with new standards and new technologies. They may be developed and maintained, as in the case of OpenGIS Specifications, by a public open consensus process. | Source: OGC |
| Open standard | “Open Standards” are standards made available to the general public and are developed (or approved) and maintained via a collaborative and consensus driven process. “Open Standards” facilitate interoperability and data exchange among different products or services and are intended for widespread adoption | Source: ITU |
| Ordnance Survey (OS) | Ordnance Survey (OS) is the national mapping agency for Great Britain, and a world-leading geospatial data and technology organisation. Serving government, business and citizens across Britain and the world, OS helps customers in virtually all sectors to improve quality of life. | Source: OS |
| Orthoimage | An orthoimage is 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. | Source:Wikipedia |
| Orthorectification | Use of photogrammetric techniques to adjust and correct distortions in images. | Source:OGC |
P
| Photogrammetry | The science, art and technology of obtaining reliable measurements and maps from aerial photographs. | Source: OS |
| Point | A position on a reference system | Source:GEMET |
| Point Cloud | A point cloud is a set of data points in space. Point clouds are generally produced by 3D scanners, which measure many points on the external surfaces of objects around them. | Source:Wikipedia |
| Polygon | Polygons are a representation of areas. A polygon is defined as a closed line or perimeter completely enclosing a contiguous space and is made up of one or more links. | Source: OS |
| Position | Data type that describes a point or geometry potentially occupied by an object or person | Source: ISO |
| Positional accuracy | The degree to which the coordinates define a point’s true position in the world, directly related to the spheroid and/or projection on which the coordinate system is based. | Source: OS |
| Postal address | Set of information which, for a postal item, allows the unambiguous determination of an actual or potential delivery point, usually combined with the specification of an addressee and/or mailee. (Universal Postal Union 2006) | Source:INSPIRE |
| Precision | The exactness with which a value is expressed, whether the value be right or wrong. | Source: OS |
| Prime meridian | Meridian from which the longitudes of other meridians are quantified | Source: ISO |
| Projected coordinate reference system | A coordinate reference system derived from a two-dimensional geodetic coordinate reference system by applying a map projection. | Source: ISO |
| Property | Plot of land and fixed objects attached to it. | Source: INSPIRE |
R
| Raster | Raster data can be thought of as being similar to a digital photograph. The entire area of the map is subdivided into a grid of tiny cells, or pixels. A value is stored in each of these cells to represent the nature of whatever is present at the corresponding location on the ground. | Source: OS |
| Register (The) | Title Register - The record created by HM Land Registry when registering ownership of land and property in England and Wales since 1862. Land and property in Scotland and Northern Ireland is governed by the separate registries of Land Register of Scotland and Land Registers of Northern Ireland. | Source:HMLR |
| Register of land | A general term used for the designation of registers for ownership of land, e.g. cadastre and registers of territorial rights. | Source: OGC |
| Registers of Scotland | Registers of Scotland (RoS) keeps public registers of land, property, and other legal documents in Scotland. They are responsible for public records, including the Land Register of Scotland and the General Register of Sasines. | Source:RoS |
| Relative position | Position of a point with respect to the positions of other points | Source:ISO |
| Relative positional accuracy | Closeness of coordinate difference value to the true or accepted value in a specified reference system | Source:ISO |
| Remote sensing | Collection and interpretation of information about an object without being in physical contact with the object | Source:ISO |
| Resolution | Resolution expresses the size of the smallest object in a spatial data set that can be described. It refers to the amount of detail that can be discerned. It is also known as granularity. | Source:INSPIRE |
| Reverse geocode | Transforms a given position into a normalized description of a feature location (Address with Point), where the address may be defined as a street address, intersection address, place name or postal code | Source:OGC |
S
| Scale | The relation between the dimensions of features on a map and the geographic objects they represent on the earth, commonly expressed as a fraction or a ratio. A map scale of 1/100,000 or 1:100,000 means that one unit of measure on the map equals 100,000 on the earth | Source:INSPIRE |
| Scanned map | Analogue maps digitized by scanning. The data structure of scanned maps is raster. | Source: OGC |
| Schema | Formal description of a data model, defining its structure, datatypes, permitted values, relationships | Source: ISO |
| Scottish Assessors | Since the enactment of the Lands Valuation (Scotland) Act 1854, Assessors have been responsible for the valuation of all heritable properties for local taxation purposes within their respective valuation areas | Source: Scottish Assessors |
| Simple feature | Feature restricted to 2D geometry with linear interpolation between vertices, having both spatial and non spatial attributes | Source: ISO |
| Source Data | Source data is raw data (sometimes called atomic data) that has not been processed for meaningful use to become Information | Source:Wikipedia |
| Spatial | Relating to the position, area, and size of things. | Source: Cambridge Dictionary |
| Spatial attribute | Feature attribute describing the spatial representation of the feature by coordinates, mathematical functions and/or boundary topology relationships | Source: ISO |
| Spatial data | Data describing anything with spatial extent; i.e. size, shape or position. In addition to describing things that are positioned relative to the Earth (also see geospatial data), spatial data may also describe things using other coordinate systems that are not related to position on the Earth, such as the size, shape and positions of cellular and sub-cellular Spatial Things described using the 2D or 3D Cartesian coordinate system of a specific tissue sample. | Source:W3C |
| Spatial object | Means an abstract representation of a real-world phenomenon related to a specific location or geographical area | Source:INSPIRE |
| Spatial operator | Function or procedure that has at least one spatial parameter in its domain or range | Source:ISO |
| Spatial reference system (SRS) | A spatial reference system (SRS) 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. | Source: Wikipedia |
| Spatial relationship | Specifies how a Spatial Thing is located in space in relation to another Spatial Thing. Typically determined using a spatial operator. | Source:W3C |
| Spatial thing | Anything with spatial extent, (i.e. size, shape, or position) and is a combination of the real-world phenomenon and its abstraction (the feature). Examples are: people, places, or bowling balls. | Source:W3C |
| Spatiotemporal | Representing a set of direct positions in space and time | Source: ISO |
| Spherical coordinate system | Three-dimensional coordinate system with one distance measured from the origin and two angular coordinates, commonly associated with a geodetic coordinate reference system | Source: ISO |
T
| Temporal reference system | Reference system against which time is measured | Source: ISO |
| Temporal thing | Anything with temporal extent, i.e. duration. e.g. the taking of a photograph, a scheduled meeting, a GPS time-stamped track-point. | Source:W3C |
| Thematic map | A map showing, by color or pattern, the distribution of a single phenomenon | Source: OGC |
| Topographic map | A map whose principal purpose is to portray the features of the earth`s surface. These features might include the cultural landscape, but normally refer to the terrain and its relief. | Source:OGC |
| Topography | The study of the physical features of the Earth. A topographic map’s principal purpose is to portray and identify the features of the Earth. | Source:OS |
| Topology | The logical relationships between interacting points, lines, and polygons that are independent of spatial values. For example, two adjacent touching polygons may be topologically independent geometries, or they may be toplogically linked by the sharing of an edge. This can enforce a skin-of-the-earth model in that if one of those polygons changes the shared edge, then the other polygon will match the change, so as to avoid overlaps or slivers. | Source: OS |
| Triangulated irregular network | This is a vector data structure that represents a surface in three dimensions. Masspoints (or z-values) are joined up as irregular triangles to form a surface to provide a more accurate and less dense method of representing a Digital Terrain Model. This is because the edges of features are preserved and masspoints are only depicted where necessary to depict changes in slope. | Source: OS |
| True north | True north (also called geodetic north) is the direction along Earth’s surface towards the geographic North Pole or True North Pole. | Source:Wikipedia |
U
| Unique object identifier | Identifier associated with a spatial object [DS-D2.5] | Source:INSPIRE (pdf, 4.2 MB) |
| Unique Property Reference Number (UPRN) | A unique numeric identifier for every spatial address in Great Britain. It provides a comprehensive, complete, consistent identifier throughout a property’s life cycle – from planning permission through to demolition. | Source: OS |
| Unique resource identifier (URI) | Uniform Resource Identifier - A Uniform Resource Identifier (URI) is a compact sequence of characters that identifies an abstract or physical resource. | Source: MEDIN |
| United Kingdom Hydrographic Office (UKHO) | The United Kingdom Hydrographic Office is the UK’s agency for providing hydrographic and marine geospatial data to mariners and maritime organisations across the world. | Source:GOV.UK |
| Unregistered land | Unregistered land in England and Wales to which title is not yet registered. Unregistered land in Scotland and Northern Ireland is governed by the separate registries of Land Register of Scotland and Land Registers of Northern Ireland. | Source: HMLR |
| Unstructured data | Any document, file, graphic, image, text, report, form, video, or sound recording that has not been tagged or otherwise structured into rows and columns or records. This term has some inaccurate connotations, as there is usually some structure (for instance, paragraphs and chapters) in these formats. | Source: DAMA |
| Universal transverse mercator coordinate system | A planar locational reference system which provides positional descriptions accurate to 1 metre in 2,500 across the entire earth`s surface into a grid which each cell, excluding overlap with its neighbours, is 6 degrees east to west, and 8 degrees north to south (with the exception of the row from 72-84 degrees north latitude), For any position in the UTM grid, X-Y coordinates can be determined in eastings and northings. Eastings are in metres with respect to a central meridian drawn through the centre of each grid zone (and given an arbitrary easting of 500,000 meters). In the northern hemisphere, northings are read in metres from the equator (0 meters). In the southern hemisphere, the equator is given the false northing of 10 million metres. | Source: OGC |
V
| Valuation Office Agency(VOA) | The Valuation Office Agency gives the government the valuations and property advice needed to support taxation and benefits. VOA is an executive agency, sponsored by HM Revenue & Customs | Source:VOA |
| Vector | A representation of the spatial extent of geographic features using geometric elements (such as point, curve, and surface) in a coordinate space. | Source: OGC |
| Vertical coordinate reference system | One-dimensional coordinate reference system based on a vertical datum | Source: ISO |
| Vertical coordinate system | One-dimensional coordinate system used for gravity-related height or depth measurements | Source: ISO |
| Vertical datum | Datum describing the relation of gravity-related heights or depths to the Earth | Source:ISO |
W
| World Wide Web Consortium (W3C) | The organisation that manages standards for the Worldwide Web. | Source:OGC |
| Web Coverage Service(WCS) | A service offering multi-dimensional (usually spatio-temporal) coverage data for access over the Internet. | Source:OGC |
| Web Feature Service(WFS) | A service that provides transactions on and access to geographic features in a manner independent of the underlying data store. | Source:OGC |
| Web Map Service(WMS) | A service that produces spatially referenced maps dynamically from geographic information. | Source:OGC |
| Web Map Tile Service(WMTS) | A service that provides a standard based solution to serve digital maps using predefined image tiles. | Source:OGC |
| World Geodetic System 1984(WGS84) | The most widely used geocentric datum and geographic coordinate system today, designed by the U.S. Department of Defense to replace WGS72. GPS measurements are based on WGS84. | Source: ESRI |
XYZ
| X-coordinate | See Longitude or Eastings |
| Y-coordinate | See Latitude or Northing |
| Z-coordinate | See Altitude or Depth |
Notes on Sources:
Where possible, links are provided to websites from which the definitions were sourced or derived. Some definitions have been modified to suit the purpose of this glossary, for example, using less specialist or technical terms to suit a wider audience.
In some cases, definitions have been derived from internal glossaries used by the Geo6 organisations, in which case a link to the organisation’s external website has been provided.