Lecture Notes - GIS for the Natural Sciences

Pedagogical Structure, etc

• The difference between learning GIS and learning GIS software

• Learning by doing

• Teaching vs Learning

• My background

• History of this class

• Grading the term

Basic GIS

• Representing things (example)

  • Points, Lines, Polygons, Raster, Tin, Attributes (like spreadsheets!)

• Measuring things

  • Categorical -discrete

  • Ordinal - discrete with order

  • Continuous - quantitative

• 2 problems: file formats and coordinate systems

• Projections and coordinate reference systems (reference ellipsoid) (Dana's overview)

  WGS84 vs NAD83

  • Lat/Long, UTM zones, State Plane (overlay example)

  • Geoid, Relationship between Geoid, Spheroid, Datum

  • NAD 27/NAD83 (North American Datum)

  • Why different coordinate systems?

  • Minimize distortion in area and/or angle

  • Parameters used in defining a projection or coordinate system

  • Reprojecting data: within the same Datum vs different Datum!

• Storing Data

• Converting Data

• Selecting Data

• Symbolizing or classifying data

• Scale: "large" vs "small"

• Maps as Models vs modeling physical systems

Types of Purposes (coastal erosion example)

• Organization

  • basic database construction, warehousing large amounts of data, ongoing updates

• Visualization

  • visual display of data shows patterns not evident in tables of data (duh!), spatial display shows patterns not evident in graphs!

• Spatial Query

  • show me all places where "X > Y". identify objects, ie "what is this thing?" (Arcview examples)

• Combination

  • also overlay analysis (often vector)
  • map modelling, eg, intersect (impose in Bonham-Carter), example: soils and geology
  • combine values from different layers with algebraic statements (often raster)
  • subset of geoprocessing, ie union, intersect

• Analysis

  • wide open, tons of possibilities
  • spatial analysis takes into account the spatial relationships, standard statistical analysis typically does not
  • single map vs multiple map
  • modeling

• Prediction

  • perhaps the ultimate goal in science!
  • detailed example from Bonham-Carter

Some map types for area data or thematic mapping

Metadata (example)

• Lineage
• Positional Accuracy
• Attribute Accuracy
• Logical Consistency
• Completeness

Anatomy of a GIS Dataset

• Shapefile
• Coverage
• Geodatabase
• Raster Imagery

Databases

• Terminology: tables, fields, records, indexes, joins

• Relational vs Hierarchical vs OO (object oriented)

• SQL (structured query language)

• Foreign key, or how do I relate multiple tables

• levels of "Normality", or "Do I sacrifice usefulness for Elegance?"

• bad example, good example

Useful stuff for scientists

• Downloading and unzipping files (illustration)

• Creating basemaps

• Creating basemaps to put your own data on

• Finding basemap layers

• Creating your own data: Digitizing, GPS, etc

• Scale issues, microscopic to intergalactic

Analysis, the payoff!

• Too tired!

• Independence and Randomness

• Analysis of point, line and polygon patterns

• Geostatistics

• Raster analysis, con() function, other algebraic functions

• Directional or Orientation analysis

• What can be done, vs what is useful, ie, computing power makes algorithms do-able, not always meaningful

Extending the GIS

• Limitations of commercial GIS

• GIS as a platform for modelling and analysis (vs programming from scratch...)

• Where to look for extensions

• Simple programming structures to "roll your own" algorithm

Image data

Environmental Modeling

Error!

Bandon Coastal Images