- 2D2-Dimensions (x,y)
- 3D3-Dimensions (x,y,z)
- 3D DrapeProjecting 2D features onto 3D surfaces.
- 4D4-Dimensions (x,y,z,time)
- 4VConcept of Big Data. Velocity (speed of transfer) of data, Variety (diversity) of data, Veracity (accuracy) of data, Volume (amount) of data.
- 9-Intersection ModelUse to model spatial relationship between topological elements.
- A Posteri ModelModel designed for exploring an established theory.
- A Priori ModelModels for modelling theories yet to be established.
- A-ScanA display of GPR trace in form of wavelets.
- AbbreviationMap Generalization technique, to compress textual information into a cleaner/crisp presentation.
- Absolute OrientationOrientation of photo in the correct datum in the real world situation, scaled and set to the correct azimuth.
- Absolute PositioningA single reciever measuring its range from the minimum of 4 satellites to define its coordinate position.
- Absolute TempretureThe temperature of an object on a scale(K,Kelvin) where 0 is taken as absolute zero (-273.15°C=0K).
- Absolute-Orientation AerotriangulationPhotograph modelling method to solve 3D positiong problem by arranging photographs in a what that projection rays intersect and the coordinates of ground control points equal to the specified values.
- AbuttalsBoundaries (or parts of boundaries) of land that are adjacent to the property/land/plot/parcel in survey.
- ACAlternating Current
- Academic KnowledgeAcademic domain knowledge, relating to the selected discipline and subjects rather than practical or technical skills.
- AccelerationRate of change of velocity over time.
- Accessibility1) The concept of how accessible an object, location, facility is for a person. 2) In spatial analysis, it refers to the measurement of the spatial relationship between two objects.
- Accessibility ModellingImage Analysis Technique. Modelling of spatial accessibility of services/facilities according to network constraints.
- AccuracyDegree of nearness of (observed) quantities to the true value, often dependent on the scale of survey and procedures used.
- Accuracy AssessmentA measure used to assess the the accuracy between known reference data and the corresponding rusult of classification.
- Achromatic ColourUnsaturated, near-neutral colour generally black, white or gray.
- Acoustic Depth SoundingSee definition on Echo Sounding.
- Acoustic Energy AttenuationEnergy absorption by medium as sound propagates, it is dependent on the frequency of sound and properties of the medium.
- Acoustic ImpedanceMeasure of opposition presented by a medium/system when acoustic pressure (e.g., sound wave) is applied.
- Acoustic IntensityMeasurement of power of sound within a medium per unit area, different to sound pressure.
- Acoustic PressureChange in pressure caused by sound energy.
- Acoustic Remote SensingRemote Sensing Technique. Use of sound waves to detect distances/locations natural phenomena (objects) underneath water/land surfaces. (E.g. SONAR, Seismogram)
- Acoustic WaveLogitudinal waves travelling with the speed of sound (dependent on medium) with properties of diffraction, reflection and interference.
- Across-track ScanningA remote sensing scanning mothod using a rotating or scillating mirror that scans the terrain along scan lines which are at right angles to the flight direction.
- Active DetectionRequires signals to be sent to the target from a transmitter for the detection from the reciever.
- Active SensorsA sensing device that both transmits and recieves reflected signals for measurement.
- Active SONAREmits sound pulses and listens for echo for distance/location detection.
- Active StationsContinuously operating reference station.
- Adaptive GainFine tuning the model as new information about measurements are received
- Additive Color ProcessMixing light of two or more different colors to create a new color. Red，green and blue are called additive primaries.
- AdjacencyA spatial relationship where multiple objects/polygons share a single side.
- Adjustment ModelsSpatial Analysis Technique. Mathematical modelling of data to adjust for: 1) Errors/Inaccuracies 2) Datum 3) Corrections
- Adverse PossessionRight/Claim of ownership of property gained through continuous occupation of land for a length of time as specified in legal documents, with evidence of occupation by claimant.
- Aerial SurveySurveys on ground features using Remote Sensing/Photogrammetric techniques.
- Aerial TriangulationSee description on Aerotriangulation.
- AerotriangulationMethod of determining position of points (ground features) based on multiple aerial photographs.
- AestheticCombination of colours, symbols, typography, and placement/orientation of objects that will be pleasing to the eye, which can help with interpretation of the information on medium.
- Affine TransformationProjective transformation perfomed on coordinates/images that preserves ratios of distances but not angles or lengths of distances.
- AfricoverThe project established by the United Nations Food and Agriculture Organization, a digital geo-referenced databased on land cover of the whole Africa.
- AggregationMap Generalization technique, to group together elements of same characteristics into a larger representative group.
- Agile DevelopmentProject Management and Software Development strategy where there is an emphasis on the creation of teams and collaboration between the people to enable continuous planning, testing and integration of solution software.
- Air baseThe ground distance between the photo center at the times of exposure.
- Airborne Remote SensingRemote Sensing Technique. Sensors are mounted on airborne devices to record images/measurements for later processing.