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- Geometric AccuracyWithin surveys (regardless of survey techniques) it refers to the geometry of the network as it can greatly affect accuracy of the data.
- Geometric CorrectionProcedures aims to compensate the systematic and essentially random or unpredictable distortions caused by sensors's factors, terrain factors and atmospheric factors.
- Geometric Dilution of PrecisionSee definition on Dilution of Precision.
- Geometric TransformationConversion/Rectification of coordinates between coordinate systems based on control points and transformation equations.
- Geopotential SurfaceSurface where gravity potential is constant.
- GeoprocessingGIS operations to manipulation data (e.g., overlay, selection ,data conversion, etc…).
- GEOREFGeospatial Reference
- GeoreferencingProcess of assigning spatial coordinates to a point with reference to a pre-existing coordinate system.
- GeoregistrationSee definition on Georeferencing.
- Georelational Data ModelInterrelated spatial data model that stores spatial data and attribute data in separately
- Geostationary OrbitA special type of Geosynchronous Orbit with a circular orbit above equator at approximately 35,786 km with orbital period approximate to Earth's rotational period thus appears to be in a fixed position in the sky.
- GeostatisticsClass of statistics focusing on spatial and/or spatiotemporal data.
- Geosynchronous OrbitOrbit of satellite around Earth with a period matchin Earth's sidereal rotation period (approx. 23hrs 56mins 2secs), satellite will return to same position in the sky every twenty-four hours.
- GeotechnicApplication of scientific and engineering principles to the interpretation, understanding, use of knowledge of Earth's crust and sub-surface material.
- GeovisualizationTools and techniques for visualizing spatial data.
- GeoWall3D stereoscopic prjection system to allow for an immersive environment.
- Gestalt PrinciplesRule of organization and perception of groups of images/shapes. Laws of Grouping: 1) Proximity 2) Similarity 3) Closure 4) Symmetry 5) Common Fate 6) Continuity 7) Good Gestalt 8) Past Experience
- GIGeological Investigation
- GISGeospatial Information System
- GIS ModellingData model (e.g., map, chart, diagram) for representing spatial objects to better understand phenomenon/system.
- Global DatumPositional data on reference system best fitted globally, often using WS84 reference system.
- Global InterpolationInterpolation method using all points in the system to estimate unknown value.
- Global Land Cover CharacterizationProduced a 1-km resolution global land cover database for the usage in a wide ragne of environmental study and modeling.
- Global Navigation Satellite SystemRussian satellite-based system, available for civillian use to, to provide positional information to compatible device.
- Global outlookGlobal perspective, including global and regional development trend and achievement in study area.
- GLONASSGLObal NAvigation Satellite System (Russia)
- GMLGeography Markup Language
- GNDVIGreen Normalized Difference Vegetation Index
- Gnomonic ProjectionNon-conformal map projection technique that displays all Great Circles as straight lines.
- GNSSGlobal Navigation Satellite System
- GoodIt exceeds the intended subject learning outcomes in some regards.
- GPRGround Penetrating Radar
- GPSGlobal Positioning Satellite
- GPS BiasesSystematic Error that affects all GPS measurements, derived coordiantes and baseline. Type: 1) Satellite Dependent: Ephemeris Uncertainties, Satellite Clock Uncertainties, Selective Availability Effects 2) Receiver Dependent: Receiver Clock Uncertainties, Reference Station Coordinate(...)
- GPS ConstellationMakes up Space Segment of GNSS, consists of a system of satellites in orbit (e.g. GPS, GALILEO, GLONASS, BeiDou)
- GPS ErrorsType: 1) Unmodelled, Residual Biases 2) Carrier Phase Cycle Slips 3) Multipath 4) Antenna Phase Centre Offset 5) Random Observation Error (Noise)
- GPS TimeTime given by all Control Stations and satellite clocks, it is regulated by UTC when GPS time was set at zeor on 6-JAN-1980 00:00.
- GradientPhysical feature of landscape defined by the Tangential angle of the horizontal, can be expressed in degrees, percentage or meters depending on circumstances and use.
- Graph TheoryThe study of graphs, used to present relations between objects by mathematical structures.
- Grasp of…Developing firm and sound understanding of overview of theology, knowledge and disciplines, including their functions and their scope of applications.
- GraticuleVisible horizontal and vertical reference lines on a telescope.
- GravelLoose rock material.
- GraybodyThe object has an less than 1 but constant emmisivity at any wavelengths.
- Graytone SymbolsSymbols expressed in different tones of gray.
- Great CircleCircle on the surface of a sphere that passes through the center of the sphere, it often represents the shortest distance between two points on the sphere and the preferred route for shipping or aircraft.
- Green Normalized Difference Vegetation IndexGreen normalized difference vegetation index, is identical in form to the NDVI and expected that the green band is substituted for the red band.
- Grid BearingType of Bearing, defined by the grid meridian and dependent on the projection coordinate system in use.
- Grid Coordinate SystemCoordinates based on an Origin (O), located at the extreme south and west of the area, with the denotation of Easting (E) and Northing (N).
- Grid FactorThe ration by which ground measurements and grid measurements varies, calculated by the scale factor and elevation factor.
- Grid LinesLines with set coordinates at each grid's corner.