AJAX progress indicator
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  • 2

  • 2D
    2-Dimensions (x,y)
  • 3

  • 3D
    3-Dimensions (x,y,z)
  • 3D Drape
    Projecting 2D features onto 3D surfaces.
  • 4

  • 4D
    4-Dimensions (x,y,z,time)
  • 4V
    Concept of Big Data. Velocity (speed of transfer) of data, Variety (diversity) of data, Veracity (accuracy) of data, Volume (amount) of data.
  • 9

  • 9-Intersection Model
    Use to model spatial relationship between topological elements.
  • a

  • A Posteri Model
    Model designed for exploring an established theory.
  • A Priori Model
    Models for modelling theories yet to be established.
  • A-Scan
    A display of GPR trace in form of wavelets.
  • Abbreviation
    Map Generalization technique, to compress textual information into a cleaner/crisp presentation.
  • Absolute Orientation
    Orientation of photo in the correct datum in the real world situation, scaled and set to the correct azimuth.
  • Absolute Positioning
    A single reciever measuring its range from the minimum of 4 satellites to define its coordinate position.
  • Absolute Tempreture
    The temperature of an object on a scale(K,Kelvin) where 0 is taken as absolute zero (-273.15°C=0K).
  • Absolute-Orientation Aerotriangulation
    Photograph 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.
  • Abuttals
    Boundaries (or parts of boundaries) of land that are adjacent to the property/land/plot/parcel in survey.
  • AC
    Alternating Current
  • Academic Knowledge
    Academic domain knowledge, relating to the selected discipline and subjects rather than practical or technical skills.
  • Acceleration
    Rate of change of velocity over time.
  • Accessibility
    1) 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 Modelling
    Image Analysis Technique. Modelling of spatial accessibility of services/facilities according to network constraints.
  • Accuracy
    Degree of nearness of (observed) quantities to the true value, often dependent on the scale of survey and procedures used.
  • Accuracy Assessment
    A measure used to assess the the accuracy between known reference data and the corresponding rusult of classification.
  • Achromatic Colour
    Unsaturated, near-neutral colour generally black, white or gray.
  • Acoustic Depth Sounding
    See definition on Echo Sounding.
  • Acoustic Energy Attenuation
    Energy absorption by medium as sound propagates, it is dependent on the frequency of sound and properties of the medium.
  • Acoustic Impedance
    Measure of opposition presented by a medium/system when acoustic pressure (e.g., sound wave) is applied.
  • Acoustic Intensity
    Measurement of power of sound within a medium per unit area, different to sound pressure.
  • Acoustic Pressure
    Change in pressure caused by sound energy.
  • Acoustic Remote Sensing
    Remote Sensing Technique. Use of sound waves to detect distances/locations natural phenomena (objects) underneath water/land surfaces. (E.g. SONAR, Seismogram)
  • Acoustic Wave
    Logitudinal waves travelling with the speed of sound (dependent on medium) with properties of diffraction, reflection and interference.
  • Across-track Scanning
    A 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 Detection
    Requires signals to be sent to the target from a transmitter for the detection from the reciever.
  • Active Sensors
    A sensing device that both transmits and recieves reflected signals for measurement.
  • Active SONAR
    Emits sound pulses and listens for echo for distance/location detection.
  • Active Stations
    Continuously operating reference station.
  • Adaptive Gain
    Fine tuning the model as new information about measurements are received
  • Additive Color Process
    Mixing light of two or more different colors to create a new color. Red,green and blue are called additive primaries.
  • Adjacency
    A spatial relationship where multiple objects/polygons share a single side.
  • Adjustment Models
    Spatial Analysis Technique. Mathematical modelling of data to adjust for: 1) Errors/Inaccuracies 2) Datum 3) Corrections
  • Adverse Possession
    Right/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 Survey
    Surveys on ground features using Remote Sensing/Photogrammetric techniques.
  • Aerial Triangulation
    See description on Aerotriangulation.
  • Aerotriangulation
    Method of determining position of points (ground features) based on multiple aerial photographs.
  • Aesthetic
    Combination 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 Transformation
    Projective transformation perfomed on coordinates/images that preserves ratios of distances but not angles or lengths of distances.
  • Africover
    The project established by the United Nations Food and Agriculture Organization, a digital geo-referenced databased on land cover of the whole Africa.
  • Aggregation
    Map Generalization technique, to group together elements of same characteristics into a larger representative group.
  • Agile Development
    Project 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 base
    The ground distance between the photo center at the times of exposure.
  • Airborne Remote Sensing
    Remote Sensing Technique. Sensors are mounted on airborne devices to record images/measurements for later processing.