AgentBased Modelling and Intergration with GIS

1
Agent-Based Modelling and Intergration with GIS

• Material and concepts borrowed from UCL Working
  Paper 110 September 2006 Principles and Concepts
  of Agent-Based Modelling for Developing
  Geospatial Simulations by Castle and Crooks
  (2006) at the following link
• http//www.casa.ucl.ac.uk/working_papers/paper110.
  pdf

2
Why model with ABM and link to GIS?

• ABM can model complex spatial relationships
• GIS has robust tools for spatial analysis
• By linking ABM and GIS, one can take advantage of
  both programs

3
Types of Models

• Analog (scale models)
• Digital Models (not dependent on scale, but
  resolution)
• Temporal resolution is also important
• Individual (disagregate) or Aggregate
• Exploratory, Explanatory, Predictive

4
Review of ABM Characteristics

• Autonomy
• Heterogeneity
• Active
• Pro-Active-Goal Directed
• Reactive-Perceptive
• Bounded Reality
• Interactive-Communative
• Mobility
• Adaptatation-Learning
• Emergernt

5
ABM and Geospatial Research

• Despite the advantages of ABM to spatial
  modelling, it has not been widely utilized
• In 1971, Schelling proved that ABM could model
  segregation
• Epstein and Axtell (1996) extended this to
  modelling people and cities to understand the
  emergence of spatial patterns (see Ethnocentrism
  and Segregation models in Netlogo)
• Their Sugarscape model showed that ABM could
  demonstrate emerging spatial patterns (See
  Starlogo under the Social Systems folder)

6
Criticisms of GIS

• Difficult to understand how GIS which is static
  can cope with dynamic processes
• GIS presently does not intergrate well with
  modelling
• Advantages of coupling with GIS is its well
  developed spatial analysis tools
• Previsiously used exclusive software and not open
  sourcenot interoperable

7
Representing Time and Space

• Two main challenges
• Continuous data over a period of time are rarely
  available
• Data models that can record and store continous
  data are still in their beginning states (Haywood
  et al. 2006)

8
Linkage-Coupling versus Intergration and Embedding

• Coupling is defined as linkage of two stand alone
  systems by data transfer
• Three types1. loose coupling-data exchanged
  between systems in form of files2. moderate
  coupling-combination between loose and
  tight/close coupling3. Tight/close
  coupling-simulateous operationof systems allowing
  direct inter-system communication (i.e.,
  Microsofts Com and .NET allow this function)
• An alternative is GIS-centric or modelling
  centric where capabilities can be called from the
  dominant system usually via a GUI (Repast uses
  GeoTools and OpenMap for visualization) Agent
  Analysts which links Repast to ArcGIS is such an
  example

9
Conclusions

• ABM is useful for modelling and capturing
  emerging phenomena
• GIS is a useful medium for developing spatial
  data and for the display of the output
• GIS-centric or modelling centric is the most
  promising to bring ABM and GIS together
• For a further examination on how Repast can be
  used in combination with GIS refer to UCL Working
  Paper 123-September 2007 The Repast
  Simulation/Modelling Sytem for Geospatial
  Simulation located at http//www.casa.ucl.ac.uk/w
  orking_papers/paper123.pdf
• (Note these links are also located on the course
  schedule at http//www.fatih.edu.tr/mcadams/geo3
  91/cal.htm )