© J.M. Piwowar 1Geog 409: Advanced Spatial Analysis & Modelling Modelling Essentials

Modelling Essentials

Model Parsimony

vs.

Model Simplicity.

© J.M. Piwowar 2Geog 409: Advanced Spatial Analysis & Modelling Modelling Essentials

Thinking Spatially

Begin by thinking about what your [spatial] output will be.You can then subdivide this spatial

information product into elements and operators.Recognize spatial patterns.Identify the processes that created the

patterns.

© J.M. Piwowar 3Geog 409: Advanced Spatial Analysis & Modelling Modelling Essentials

Visible Patterns

© J.M. Piwowar 4Geog 409: Advanced Spatial Analysis & Modelling Modelling Essentials

Visible Patterns

© J.M. Piwowar 5Geog 409: Advanced Spatial Analysis & Modelling Modelling Essentials

Visible Patterns

Measuring Visible Patterns - Landscape Metrics# of patches / areaPatch sizes & shapesPatch densities & inter-patch distancesIsolation metricsPerimeter-to-area ratiosOrientations

© J.M. Piwowar 6Geog 409: Advanced Spatial Analysis & Modelling Modelling Essentials

Functional Patterns

Not readily visible. Latent Patterns:

Threshold dependent

Temporally unique

© J.M. Piwowar 7Geog 409: Advanced Spatial Analysis & Modelling Modelling Essentials

Tools for Identifying Patterns

The LandscapeVisual observations by domain experts.

Not necessarily the same as the GIS modeller.

Observations should be made:At different times of the day;In different seasons;From different perspectives;With different viewing tools.

© J.M. Piwowar 8Geog 409: Advanced Spatial Analysis & Modelling Modelling Essentials

Tools for Identifying Patterns

Literature SurveysWithin-domain surveys.Extra-domain surveys.

Knowledge EngineeringDomain experts.Expert Systems.

© J.M. Piwowar 9Geog 409: Advanced Spatial Analysis & Modelling Modelling Essentials

Tools for Identifying Patterns

MapsVariations in themes, scales,

projections, perspectives, dimensionalities, symbolisms …

Aerial PhotographyVariations in tone, colour, texture,

setting, scale, association, time …

© J.M. Piwowar 10Geog 409: Advanced Spatial Analysis & Modelling Modelling Essentials

Tools for Identifying Patterns

Satellite ImageryVariations in spectral, spatial, temporal,

radiometric resolutions.Digital image analysis.

Statistical TechniquesDescriptive stats.Correlation, regression.Central tendency; spatial dispersion.

© J.M. Piwowar 11Geog 409: Advanced Spatial Analysis & Modelling Modelling Essentials

From Pattern to Process

Recognizing the spatial interactions of the problem

Sometimes determining the underlying processes that created the patterns; sometimes evaluating the effects of existing patterns on on-going processes.

© J.M. Piwowar 12Geog 409: Advanced Spatial Analysis & Modelling Modelling Essentials

From Pattern to Process

Go beyond pattern recognition into pattern description.

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© J.M. Piwowar 13Geog 409: Advanced Spatial Analysis & Modelling Modelling Essentials

Types of GIS Models

Purpose ModelsDescriptive Models

Describe parts or all of a study area.Passive.E.g. a map.

Prescriptive ModelsPrescribe best solutions.Active.E.g. best location analysis

© J.M. Piwowar 14Geog 409: Advanced Spatial Analysis & Modelling Modelling Essentials

Types of GIS Models

Methodological ModelsDeterministicStochastic

Logistic ModelsInductiveDeductive