www.spatialanalysisonline.com

Chapter 3

Methodological context

3rd edition www.spatialanalysisonline.com 2

Spatial analysis as a process

Problem formulationData gatheringExploratory analysisHypothesis formulationModelling and testingConsultation and reviewReporting and implementation

3rd edition www.spatialanalysisonline.com 3

Analytical methodologies

Mitchell (2005) Draper et al (2005)

3rd edition www.spatialanalysisonline.com 4

Analytical methodologies - PPDAC

After Mackay & Oldford (2002)

3rd edition www.spatialanalysisonline.com 5

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 …

3rd edition www.spatialanalysisonline.com 6

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

3rd edition www.spatialanalysisonline.com 7

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

3rd edition www.spatialanalysisonline.com 8

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

3rd edition www.spatialanalysisonline.com 9

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

3rd edition www.spatialanalysisonline.com 10

PPDAC – Data phase

Data quality & sourcing issues Quality Cost Licensing Availability Completeness & consistency Timeliness Detail/resolution Intangible/qualitative data

3rd edition www.spatialanalysisonline.com 11

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

3rd edition www.spatialanalysisonline.com 12

PPDAC – Data phase

Changing context Spatial Data Infrastructures Geoportals Metadata New data capture tools Changes in data visualisation & usage Interdisciplinary nature of geospatial analysis

3rd edition www.spatialanalysisonline.com 13

PPDAC – Analysis Phase

Simplicity and parsimonyExploratory analysis & visualisationInterpretation of spatial patternsConstruction of hypothesesBuild-test-criticise ‘model’ cycleDeveloping preliminary conclusionsMatch to expectations?

3rd edition www.spatialanalysisonline.com 14

PPDAC – Analysis Phase

Types of modelMathematical/Statistical modelsCartographic modelingFlow modelsMicro-scale modeling... etc

3rd edition www.spatialanalysisonline.com 15

PPDAC – Analysis Phase

Simple dynamic cartographic model

3rd edition www.spatialanalysisonline.com 16

PPDAC – Analysis Phase

Sample risk assessment model output

3rd edition www.spatialanalysisonline.com 17

PPDAC – Conclusion Phase

Expectations on delivery met?Simplicity againClear/high quality visualisationIdentify and report strengths, weaknesses

and possible sources of errorRecommendationsFuture actions

3rd edition www.spatialanalysisonline.com 18

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