Geographic Information Systems
Module Outline
Mark Foley
mark.foley@dit.ie
Topics
What is GIS?
Spatial data
Spatial data modelling
Database management
Data input and editing
Data analysis
Analytical modelling in GIS
Output: from new maps to enhanced decisions
The development of computer methods for handling spatial data
Data quality issues
Human and organizational issues
GIS project design and management
The future of GIS
What is GIS?
Introduction
GIS definition
Generic types of questions GIS can answer
GIS components
Hardware
Software
Data
Procedures (‘orgware’)
People
Case studies
Example: Happy Valley
Example: nuclear waste disposal site search
Example: land use planning in Zdarske Vrchy
Example: house hunting
Application areas of GIS
Spatial data
Introduction
Types of data model
Data sources
Maps and their influence on the character of spatial data
Purpose
Scale
Spatial entities
Generalization
Projections
Spatial referencing
Geographic coordinate systems
Rectangular coordinate systems
Non-coordinate systems
Topology
Thematic characteristics of spatial data
Entity types
Scales of measurement
Sources of spatial data
Maps
Census and survey data
Aerial photographs
Satellite imagery
Field survey and GPS
Data issues
Data quality
Data standards
Spatial data modelling
Introduction
Entity definition
Points, lines and areas
Surfaces
Networks
Spatial data models
Raster
Simple raster
Quadtrees
Vector
Spatial data structures
Raster
Vector
Modelling surfaces
Raster DTMs
TINs
Modelling networks
Building computer worlds
Layer-based models
Object-oriented models
Modelling the third dimension
Modelling the fourth dimension
Database management
Introduction
Why we need to handle attribute data
Using databases to handle attribute data
Database management systems (DBMS)
Database models
Relational databases
Creating a database
What steps are required?
Making the link between spatial and attribute data
Database applications in GIS
Feature attribute tables
Web-based databases
Object-oriented databases
Data input and editing
Introduction
The data stream
Methods of data input
Keyboard entry
Manual digitizing
Automatic digitizing
Electronic data transfer
Data editing
Detecting and correcting errors
Attribute and spatial data checking
Re-projection, transformation and generalization
Edge matching and rubber sheeting
Developing an integrated database
Data analysis
Introduction
Analytical functionality in GIS
The Happy Valley example
Measurement
Length (distance)
Perimeter
Area
Queries
Reclassification
Boolean operators
Buffering and neighbourhood functions
Map overlay
Vector
Point-in-polygon
Union, erase and intersect
Raster
Cartographic modelling
The nuclear waste disposal site search example
Problems and issues in overlay
Spatial interpolation
Deriving continuous surfaces from discrete point data
Classification of interpolation methods
Analysis of surfaces
Slope and aspect
Visibility
Network analysis
Shortest path
Travelling salesperson
Location-allocation modelling
Route tracing
Quantitative spatial analysis
Analytical modelling in GIS
Introduction
Reminder about models
Process models
Model types: natural/scale, conceptual, mathematical, process
Example: Happy Valley snow cover model
Linking models to GIS
Modelling physical and environmental processes
Modelling human process
Decision making with GIS
Multi-criteria evaluation (MCE)
Public participation GIS (PPGIS)
Problems with modelling
Output: from new maps to enhanced decisions
Introduction
The range of GIS outputs
Maps as the principal form of GIS output
Cartographic rules
Choropleth mapping
Alternative forms of cartographic output
Non-cartographic output
Multimedia
Serving maps on the web
VRGIS
Decision support as a form of output
Maps as decision tools
Example: Zdarske Vrchy
Example: nuclear waste disposal
The development of computer methods for handling spatial data
Introduction
Pre-GIS: handling spatial data manually
The advent of the computer
Graphics
Data access and storage
Data input
The development of computer methods for handling spatial data
Systems approach
Computer cartography
Spatial statistics
AM/FM and CAD
Web and mobile GIS
The development of GIS
1970s
1980s
1990s
2000s
Case studies in GIS development
CGIS: example of early GIS
ESRI: example of market leader
CORINE: example of GIS project
The diffusion of GIS
Data quality issues
Introduction
The language of data quality
The importance of quality control
Describing quality
Accuracy
Precision
Error
Uncertainty
Bias
Completeness, compatibility, consistency and applicability
Sources of error in GIS
Understanding and modelling reality
Source data
Encoding errors
Digitizing error
Data editing and conversion
Rasterization errors
Vectorization errors
Processing and analysis errors
Output errors
Finding and modelling errors
Error checking
Error modelling
Managing error
The future of GIS
Introduction
Where next for GIS?
Applications
Technology
Information
People
Exploring the future for GIS
Natural disasters
Daddy, what does lost mean?
The ad man's dream