GIS Summary

GIS Summary
- components
  - computer system
    - hardware
    - operating system
    - GIS (& other) software
  - geographic data
    - attribute
      - measurement scales
        
        nominal - cities
        
        ordinal - stream types (S1-S6)
        
        interval - temperature
        
        ratio - precipitation, volume
      - resides in ...
        
        pixels (raster)
        
        data table (vector)
      - Database
        
        terms
        
        database
        
        record / field / value
        
        primary key / secondary key
        
        relational database
        
        each 'subject' has its own table
        
        tables can be related
        
        advantages
        
        GIS context (vector)
        
        attribute data in tables
        
        spatial data in tables
        
        these tables are linked ...
    - Spatial Data
      - projections
      - georeferencing
      - spatial entities
        
        point
        
        line / network
        
        polygons
        
        surface (a.k.a. "field")
      - sources
        
        base maps - gov't (TRIM)
        
        thematic maps (inventory)
        
        images
        
        field (GPS, RoadEng)
      - Spatial Data Model
        
        real world
        
        conceptual model
        
        discrete objects vs. "field"
        
        is the forest (volume) a collection of objects or a field?
        
        logical (GIS) model
        
        vector
        
        spatial = points, lines & polygons
        
        attribute = data tables
        
        raster
        
        spatial = grid of pixels (cells)
        
        attribute = values in the pixels
        
        physical model (not covered)
      - Data Quality
        
        terms
        
        error (uncertainty)
        
        absolute vs. relative
        
        resolution
        
        generalization
        
        completeness
        
        consistency
        
        compatibility (to other data sets)
        
        applicable (to analysis to be done)
        
        sources
        
        data modeling
        
        forest: point, polygons or surface
        
        understanding ... data collection ... analysis
        
        original data capture
        
        data encoding (digitizing)
        
        combining maps
        
        rubber sheeting & edge matching
        
        generalization
        
        metadata
  - functions
    - Data Input & Maintain
      - data sources
        
        field (GPS, survey)
        
        orthophotos & satellite & LiDAR
        
        paper --> digital
        
        digitize or scan
        
        fix errors
        
        topology
        
        for vector maps
        
        shared geometry of features
        
        adjacency
        
        containment
        
        connectivity
        
        enforces data intergrity
        
        allows for relational analyses
      - update (new features)
    - Analysis
      - Vector
        
        Attribute
        
        query
        
        math calculation
        
        summarize
        
        relate/join tables
        
        Spatial
        
        spatial calculation
        
        select by location
        
        buffer
        
        overlays
        
        merge
        
        dissolve
        
        spatial join
      - Raster
        
        reclassify
        
        calculator
        
        spatial interpolation
        
        surface
        
        distance
      - Analytical Modeling
        
        boxes and arrows
        
        "rules"
    - Output/ Cartography
      - symbology
        
        qualitative (nominal or ordinal)
        
        quantitative (interval or ratio)
      - Design
        
        concept before compilation
        
        hierarchy with harmony
        
        simplicity from sacrifice
        
        max info at min cost
        
        engage emotions
  - organization / people
    - technician
    - analyst
    - manager
- definition
  - system?
  - information system?
  - GIS?