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Chapter 3
Methodological context
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Spatial analysis as a process
Problem formulationData gatheringExploratory analysisHypothesis formulationModelling and testingConsultation and reviewReporting and implementation
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Analytical methodologies
Mitchell (2005) Draper et al (2005)
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Analytical methodologies - PPDAC
After Mackay & Oldford (2002)
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PPDAC
Views spatial analysis in a broader contextModel is highly iterativeAnalysis is just part of the processConsiders the process flow in reverseSpatial is special – extending the PPDAC
methodology …
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PPDAC
Extended PPDAC for spatial analysis Spatial focus – spatial relationships and spatial
dependence Spatio-temporal focus Failure to meet classical statistical criteria Pattern and process relationship Spatial data sourcing and quality
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PPDAC – Problem phase Problem definition
Clear definition of problem/project and (client) expectations is paramount
Desk research as part of initial process Identification of specific spatial issues:
spatial (and statistical) scale factors spatial arrangement factors data availability and quality spatial grouping issues
ecological fallacy, atomistic fallacy
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PPDAC – Plan phase Nature of project Costing requirements Decision-support requirements Public participation issues Operational requirements Timing and critical dates Funding and resourcing Feasibility and risk analysis Client expectations
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PPDAC – Plan phase – cont. Specifications and standards Data components required Data sourcing and augmenting Sampling, populations and inference Adopting multiple approaches Seeking robustness Testing/simulating the process flow Handling exceptions & rare events Re-examining the problem specification
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PPDAC – Data phase
Data quality & sourcing issues Quality Cost Licensing Availability Completeness & consistency Timeliness Detail/resolution Intangible/qualitative data
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PPDAC – Data phase
Data quality & GIS tools - examples Boundary definition and density computation Missing data handling and masking Classification Data transformation Breakline handling Error mapping Simulation
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PPDAC – Data phase
Changing context Spatial Data Infrastructures Geoportals Metadata New data capture tools Changes in data visualisation & usage Interdisciplinary nature of geospatial analysis
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PPDAC – Analysis Phase
Simplicity and parsimonyExploratory analysis & visualisationInterpretation of spatial patternsConstruction of hypothesesBuild-test-criticise ‘model’ cycleDeveloping preliminary conclusionsMatch to expectations?
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PPDAC – Analysis Phase
Types of modelMathematical/Statistical modelsCartographic modelingFlow modelsMicro-scale modeling... etc
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PPDAC – Analysis Phase
Simple dynamic cartographic model
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PPDAC – Analysis Phase
Sample risk assessment model output
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PPDAC – Conclusion Phase
Expectations on delivery met?Simplicity againClear/high quality visualisationIdentify and report strengths, weaknesses
and possible sources of errorRecommendationsFuture actions
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PPDAC – Final comments
Work through and specify each model step before commencing – test out ideas
Identify risk areas and revisit PPDAC elements as required
Confirm overall programme and deliverables with ‘client’
Manage risks and changes