GRB

AJAX progress indicator
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  • a

  • Archipelago
    Group of islands.
  • Area Aggregation
    A form of generalization, it is grouping areas of similar characteristics to simplify the map, may cause misinterpretation or bias.
  • Area-pattern Analysis
    Spatial Analysis Technique. Analysis of choropleth map to determine pattern of specified area (e.g. randomness, uniformity, clusters, etc…)
  • Areal Distortion
    Distortion on areal properties of maps due to projection and transformation, areas displayed may not reflect reality and can be sometimes exaggerated.
  • Areal Interpolation
    Transfer of data from source polygons to target polygons.
  • Arid Climate
    The climate in areas that receive less than 50 cm per year rainfall.
  • ARMA
    AutoRegressive Moving Average
  • Array
    Collection of data/cell values that can be selected by indices.
  • Articulate
    Clearly express and state ideas
  • AS
    Anti-Spoofing
  • As-built Survey
    Surveys to document location and layout of engineering works, record of design changes during construction.
  • ASCII
    American Standard Code for Information Interchange
  • Aspatial Query
    Questioning GIS data based on non-spatial attributes.
  • Aspect
    Compass direction of slope face
  • Aspect Ratio
    The ration between pixel width and heigth
  • Association
    Map Generalization technique, to connect different elements together (generally textual elements with pictorial elements).
  • Association Rules (Analysis)
    The analysis of the spatial relationship between two associated objects comparing against one-another.
  • Astronomic Latitude
    Calculated from angles measured between zenith and to known stars, it is the angel between the Earth's equatorial plane and the true vertical at an point on the surface.
  • Astronomical Coordinate System
    Positioning system for celestial objects (i.e. satellites, plantes, stars) in a 3-D space (celestial sphere). Type: 1) Horizontal System 2) Equatorial System 3) Ecliptic System 4) Galactic System 5) Super Galactic System
  • Atlas
    Book of map/charts.
  • Atmosphere
    The layer of gas surrounding the Earth. Type: 1) Troposphere 2) Stratosphere 3) Mesophere 4) Thermosphere 5) Exosphere
  • Atmospheric Correction
    Taking into account the properties of light and its characteristics in the air, it is the process of removing the atmostpheric effects on observations/measurements/images.
  • Atmospheric Windows
    The range of wavelength in which the atmosphere is particularly transmissive of energy.
  • Attenuation
    Gradual loss of energy due to medium of transmission.
  • Attribute
    Non-spatial information about a geographical features linked to the stored values of a GIS.
  • Attribute Data
    Descriptions and/or classifications of geographical features on a map. Types: 1) Nominal 2) Ordinal 3) Interval 4) Ratio
  • Attribute Domains
    Defines that allowable values for fields in a feature class or attribute table.
  • Attribute Error
    Attributes of features on GIS that are incorrectly recorded.
  • Attribute Type
    Determines how data is stored in GIS, can be defined by its type (e.g., number, text, binary object, date) or scale (e.g., nominal, ordinal, interval, ratio).
  • Augmented Reality
    Composite view of both the real-world and computer generated world, where real world experience of the environment is augmented by computer generated sensory input (i.e. sound, video, graphics, GPS data, etc…)
  • Authalic Sphere
    A generalised model of the Earth where the spherical model has the same surface area as the reference ellipsoid.
  • Autocorrelation
    Correlation of values of nearby datasets.
  • Automatic Level
    Self-levelling telescopic device for Level Runs with in-built conpensating device (automatic compensators) to correct residual mislevelment.
  • Autonomous Positioning
    Uncorrected position calculated by the reciever using Code measurements.
  • AutoRegressive Moving Average
    Method of non-Fourier spectral estimation, a statistical analysis of a time series.
  • AUV
    Autonomous Underwater Vehicles
  • Average
    Quantity for expressing the central/most typical value of dataset, calculated by dividing sum of values of numbers in dataset.
  • Azimuth
    Horizontal angles observed clockwise from reference meridian.
  • Azimuthal Projections
    Map projection where area is projected onto a tangential plane to the surface, generally at Poles or Equator. Types: 1) Azimuthal Equidistant 2) Lambert Azimuthal Area 3) Azimuthal Conformal Projection (Stereographic Projection) 4) Orthographic Projection 5) Gnomonic Projection
  • b

  • B-Scan
    Cross sectional image display produced by GPR, compilationo f multiple traces by GPR.
  • Background Knowledge
    Prerequisite knowledge, should be acquired before the formal lectures or practices
  • Backsight
    First reading of height measurement on level run towards the back staff on a single setup.
  • Backwater
    Body of stagnant (still) water in a river not reached by current.
  • Band Ratio
    A digital image-processing technique to enhance contrast between featuresn through dividing a measure of reflectance for the pixels in one image band by the other one.
  • Banding
    A type of systematic noise of image, caused by multispectral scanners that sweep multiple scan lines simultaneously.
  • Bandpass Filter
    Bandpass filter is usded to block the wavelength exceeding a specific range.
  • Bandwidth
    Range of frequency in a given band.
  • Bank
    Land mass alongside boundary between water bodies and land.
  • Bank Monitoring Surveys
    Surveys performed on waterways, estuaries, and coastlines of areas suspected to be subjected to erosion and material movement.
  • Bar Check Calibration
    On-site calibration for echo sounders using a reference bar.