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Weeks 1-3 (RASTER SPATIAL ANALYSIS (Data Analysis Tools (Focal…

- - - - polygon--results in extracted area
    - - Region group contiguous cells
      - Aggregate
        lower resolution raster
  - - - rectangles, circles, annuluses, wedges
      - new value calc from neighborhood
      - moving window of define neighborhood size
    - - can be multiple zones across multiple rasters
      - group of cells of same values or like features (contiguous or non contiguous)
    - - mathematical operations
        
        map algebra
      - reclassification
        
        create new raster values from old values
      - overlays
        
        each layer holds 1 value, output is math expression of those values
    - - physical distance measure operations
        
        straight-line or euclidean distance
        
        cost distance takes into account distance and "costs" traversing cells
        
        similar to buffer, coarser b/c whole cell is width
      - all of cells in input raster
  - - - use stretched or classified
    - - use classified or stretched if ratio
      - use unique values if nominal/ordinal
- - - - discrete data --> integers
      - continuous data --> floating point
  - - - Relates= multiple matches btwn origin and destination tables
      - Joins= unique match btwn origin and destination tables
        
        Many to 1
        
        1:1
        
        Many to Many
        
        1: many
- - - - Project= Change SRS
      - Define Projection= define SRS
    - - units are in angular measurements of degrees (lat long)
        
        DD = Degrees + (Minutes / 60) +
        (Seconds /3600)
        If “W” or “S”, make negative
        If “N” or “E”, make positive
        ex. 45°12’ 32” N = 45.2001
        
        Accuracy in DMS
        To maintain 1 meter accuracy we need to
        keep at least 5 digits after the decimal place!
    - - units are linear (km, mi, ft)
      - X, Y
        Easting, Northing
  - - - measure positions (lat + long)
      - NAD 27-- datum shift 100-400m
        NAD 83
        WGS 84
        High Accuracy Reference Network (HARN)
    - - Tidal datums
        
        water level, measure local mean sea level
        
        relationships to geodetic datum established by connecting tidal bench mark networks to NSRS
      - Ellipsoidal datums
        
        WGS84
        NAD 83
        ITRF (intl terrestiral reference frame)
        
        defined by referenced ellipsoid and 6 geocentric parameters expressing origin + orientation
        
        3 dimensional datum (unlike horizontal datum) foundation for accurate det of ellipsoidal heights
      - Orthometric (Geodetic datums)
        
        NAVD 88
        
        Father Point, Rimouski,
        Quebec, Canada
        
        Geoid= specified equipotential surface of Earth gravity field which best fits global mean sea level-----> as if whole earth were covered in water
        
        Orthometric height = (ellipsoidal height from GPS) - (Geoid height)
  - - - city and county govt's, units ft
      - each state has one or more zones
    - - Mercator Distortion
      - Lines of longitude are equi-distant
        Lines of latitude are greatly distorted @ poles
      - UTM, Geographic for North-South
        
        state govt's
        
        120 zones, units= meters
        
        each zones has own UTM projection, min distortion
    - - Tissot Indicatrix
      - A country in the tropics asks for a
        cylindrical projection.
        A country in the temperate zone asks for a
        conical projection.
        A polar area asks for an azimuthal
        projection.
    - - UTM, Lambert Conformal conic
    - - UTM, Lambert Cylindrical Equal-Area
- - - - ArcGis Geodatabase
        
        dataset tables: spatial data w/ geometry + attributes of vector/raster data
        
        system tables: keep track of contents of gdb
        --specifies dataset definitions, rules, behavior
        --storage of topological rules
  - - - ArcView Shapefiles
        
        composed of multiple files...dbf, prj, sbn
    - - ArcInfo Coverages
        
        line coverage
        
        polygon coverage
        
        point coverage