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GIS I - GROUP TWO (GNSS (Differential Correction (Real Time (Kinematic and…

- - - - occur because speed of light is assumed to be constant when it is not, therefore calculations are slightly inaccurate
      - to correct range error, adjust value used for speed of light when calculating range distance
    - - larger for satellites with lower horizon angles
      - satellites with high horizon angles (high above horizon) have less errors
      - to improve accuracy screen satellites based on horizon levels, only using those with larger horizon angles
  - - - Kinematic and Virtual Reference
  - - - noting of location and/or movement of objects through time
    - - providing directions and/or routes to selected points
    - - data recorded in field to update point line, or area locations
      - capture both coordinate and attribute data in field
      - primary application
- - - - relief distortion affects angles and distances on an image
  - - - frequency
        
        number of cycles of a wave passing through a specific point per unit time
        
        measured in MHz
      - wavelength
        
        length of one wave cycle
        
        measured in micrometers
    - - passive remote sensing sysem
        
        Not useful in cloudy/hazy conditions
        
        Use energy from sun that's reflected off the target object, then measured by sensor
      - active remote sensing system
        
        data can be collected during cloudy or nighttime conditions
        
        sends out an energy signal then measures the signal that’s reflected back to sensor
- - - - proximity
        
        are within distance of
      - adjacency
        
        features touching
      - intersection
        
        are crossed by
      - containment
        
        features contained or surrounded by
  - - - looks for obvious breaks and attempts to identify naturally occurring clusters of data
    - - specifies the number of output classes and requests equal interval classes over the range output values
  - - - used to combine features that are similar within the data layer
      - a value or set of values that belong in the same grouping is identified and the values for the dissolve attribute are compared across the boundary line .if the values are the same the boundary line is removed, or dissolved, away
    - - a region that is less than or equal to a specified distance from one or more features
      - may be used in raster or vector datasets
      - often used because many spatial analyses are concerned with distance constraints
- - - - Relatively low resolution
      - most effective when combined with other raster files (i.e. DEMs and orthophotos)
    - - High resolution
      - can be used as a base to calculate slope and aspect
    - - Low resolution
      - provides image quality of photograph with measurable attributes of map
    - - Relatively high resolution
      - provides detail regarding topological variability
    - - each has value to represent characteristic of a location
      - Cell dimension
    - - Run length coding
      - Quad tree
    - - representing multispectral data (i.e. satellite images)
      - representing pictures
      - representing continuous spatial fields
      - analyzing spatial relationships among features
    - - Map Algebra
        
        The cell by cell combination of raster data layers
        
        Unary
        
        Only applied to one layer
        
        Binary
        
        Applied to two layers
        
        Sumlayer = layer A + Layer B
        
        Higher Order Operations
        
        Involves many layers
      - Local Functions
        
        Mathematical Functions
        
        Can create new data layers by applying mathematical functions on a cell by cell basis to input layers
        
        Logical Operations
        
        Also known as Boolean Operations
        
        AND
        
        OR
        
        NOT
        
        XOR
        
        Reclassification
        
        assigns output values that depend on the specific set of input values
        
        Nested Functions
        
        When a function is used as the argument of another function
        
        Overlay
        
        Combines features from two or more data layers. Restricted to nominal data. Involves cell by cell comparison of values in two or more layers.
  - - - Connectivity
      - Adjacency
      - Planarity
    - - Objects
        
        points
        
        Nodes
        
        Polygons
        
        Inclusions
        
        Boundary generalization
        
        Areas
        
        lines
        
        Arcs
      - Used for:
        
        dissolving boundaries or merging polygons into large objects
        
        topology-based analysis
        
        storing features with distinct boundaries
        
        attribute queries and selection based analysis
  - - - One-to-one linkage (most common)
      - Many-to-one linkage
      - Cluster of underlying file structures
    - - Many-to-one linkage (most common)
      - One-to-one linkage but within a contiguous group
- - - - WorldView
        
        Worldview-3: Panchromatic images with maximum resolution of 31 cm. Addition of 8 bands at 1.24 m resolution, 8 shortwave infrared bands at 3.7 m resolution and 12 bands at 30 m resolution. Images collected at 13.1 km swath width at nadir and off-nadir at poorer than 30 cm resolution. Can image entire globe at 50 cm resolution.
        Worldview-2: Panchromatic images at 0.46 m resolution and multi-spectral images at 1.8 m resolution. Swath width at about 17 km.
        Worldview-1: Panchromatic images at 0.5 m resolution. Swath width at about 17 km.
      - GeoEye
        
        Panchromatic images at 46 cm resolution and multi-spectral images spanning wavelengths from blue through near-infrared at 1.84 m resolution. Nominal 15.2 km scan with nadir.
      - Pleiades
        
        Panchromatic images with 46 cm resolution. Multi-spectral images spanning wavelength from blue to near infrared at 1.84 m resolution. Nominal 15.2 km scan with nadir and off-nadir imaging.
      - SPOT
        
        SPOT-6 and -7: Panchromatic images at 1.5 m resolution as well as 4 bands spanning wavelength from visible through near-infrared and multi-spectral images at 6 m resolution. 60 km swath path at nadir. 15 to 40 times larger area coverage than the highest resolution satellites.
  - - - SPOT-5
      - LANDSAT
      - Resourcesat
      - RapidEye
  - - - MERIS
      - MODIS (Moderate Resolution Imagine Sensor)
        
        VIIRS
      - VEGETATION
- - - - Used to describe a point on the earth's surface
        
        NAD (North American Datum)
        
        NAD27: Developed for measurements of the US and North American. Center point positioned at Meades Ranch, Kansas.
        
        NAD83: Developed by the National Geodetic Survey and Canadian agencies, is used as the datum for much data for the US and the North American continent as a whole.
        
        WGS (World Geodetic System)
        
        WGS84: Developed by the US Department of Defense, used by GPS for locating points world wide on Earth's surface.
        
        ITRF (International Terrestrial Reference Frames)
        
        Used worldwide, primary purpose is to estimate crustal deformation and continental drift by measuring the location and velocity of points. Can be considered equivalent to WGS84.
    - - Measurement point from which elevation is determined often paired with horizontal datums
      - NGVD29: vertical datum paired with NAD27
      - NAVD88: vertical datum paired with NAD83
  - - - Azimuthal
        
        Perspectives
        
        Gnomonic
        
        View from the center of globe looking out
        
        Orthographic
        
        View from the opposite side of globe looking through the globe
        
        Stereographic
        
        Parallel line view from beyond globe
    - - Conic
        
        Lambert Conformal Conic
        
        Distortion least near intersecting parallels (East-West) and increases further from those parallels
        
        Preserves shape and direction
    - - Cylindrical
        
        Transverse Mercator
        
        Distortion least near central meridian (North-South) and increases further from this
    - - Secants (line where developable surface intersects globe)
      - Tangent (point or line where developable surface touches the globe)
      - Great circle (plane that bisects globe)
    - - Space
      - Area
      - Distance
      - Direction