Introduction to Geographic Information Analysis

SERGIO REY

Geographic Information AnalysisSchool of Geographical Sciences and Urban Planning

Arizona State University

Geographic Information Analysis by Sergio Reyis licensed under a Creative Commons Attribution 4.0 International License.

1 GIS and Spatial AnalysisBig PictureWhat is Spatial Analysis?

2 EDA and ESDAExploratory Data Analysis (EDA)Exploratory Spatial Data Analysis (ESDA)

c© 2015- Sergio Rey Geographic Information Analysis http://sergerey.org

Outline

1 GIS and Spatial AnalysisBig PictureWhat is Spatial Analysis?

2 EDA and ESDAExploratory Data Analysis (EDA)Exploratory Spatial Data Analysis (ESDA)

c© 2015- Sergio Rey Geographic Information Analysis http://sergerey.org

GIS Then

c© 2015- Sergio Rey Geographic Information Analysis http://sergerey.org

GIS Then

c© 2015- Sergio Rey Geographic Information Analysis http://sergerey.org

GIS Now

c© 2015- Sergio Rey Geographic Information Analysis http://sergerey.org

GIS Functions

Anselin-Getis (1992) TaxonomyInputStorageAnalysisOutput

Many other taxonomies

c© 2015- Sergio Rey Geographic Information Analysis http://sergerey.org

GIScience

Goodchild (1992)cross-disciplinarycentral role for spatial analysisscientific glue

c© 2015- Sergio Rey Geographic Information Analysis http://sergerey.org

Outline

1 GIS and Spatial AnalysisBig PictureWhat is Spatial Analysis?

2 EDA and ESDAExploratory Data Analysis (EDA)Exploratory Spatial Data Analysis (ESDA)

c© 2015- Sergio Rey Geographic Information Analysis http://sergerey.org

What is Spatial Analysis?

From Data to InformationBeyond mappingadded valuetransformations, manipulations and application of analyticalmethods to spatial (geographic data)

c© 2015- Sergio Rey Geographic Information Analysis http://sergerey.org

Locational Invariance

How Insights Change with locationspatial analysis is not locationally invariantthe results change when the locations of the study objects changewhere matters

c© 2015- Sergio Rey Geographic Information Analysis http://sergerey.org

State Income Distributions 1929

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State Income Distributions 1929

c© 2015- Sergio Rey Geographic Information Analysis http://sergerey.org

Randomized Income Distribution 1929

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Randomized Income Density 1929

c© 2015- Sergio Rey Geographic Information Analysis http://sergerey.org

Locational Invariance

c© 2015- Sergio Rey Geographic Information Analysis http://sergerey.org

Spatial Autocorrelation Income 1929

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Spatial Autocorrelation Randomized Income 1929

c© 2015- Sergio Rey Geographic Information Analysis http://sergerey.org

Locational Variance

c© 2015- Sergio Rey Geographic Information Analysis http://sergerey.org

Components of Spatial Analysis

Mapping and Geovisualizationshowing interesting patterns

Exploratory Spatial Data Analysisdiscovering interesting patterns

Spatial Modelingexplaining interesting patterns

c© 2015- Sergio Rey Geographic Information Analysis http://sergerey.org

Summary: Spatial Analysis

Beyond MappingCentral role for analysis

Distinguished by Locational VarianceLocation matters

ComponentsShowing, discovering, explaining

c© 2015- Sergio Rey Geographic Information Analysis http://sergerey.org

Outline

1 GIS and Spatial AnalysisBig PictureWhat is Spatial Analysis?

2 EDA and ESDAExploratory Data Analysis (EDA)Exploratory Spatial Data Analysis (ESDA)

c© 2015- Sergio Rey Geographic Information Analysis http://sergerey.org

EDA: John Tukey (1977)

EDA is an approach, notsimply a set oftechniques, but anattitude/philosophyabout how a dataanalysis should becarried out.Postpones the usualassumptions about whatkind of model the datafollow

c© 2015- Sergio Rey Geographic Information Analysis http://sergerey.org

Goals and Purpose of EDA

Set of techniques tomaximize insight into a data setuncover underlying structuresextract important variablesdetect outliers and anomaliestest underlying assumptionssuggest hypothesesdevelop parsimonious models

c© 2015- Sergio Rey Geographic Information Analysis http://sergerey.org

EDA Components

c© 2015- Sergio Rey Geographic Information Analysis http://sergerey.org

EDA Techniques

Statistical GraphicsEDA relies heavily on statistical graphicsEDA is not identical to statistical graphicsGraphics support pattern recognition and open-mindedexplorationInteractive graphics push this even further

Quantitative MethodsAlthough heavily graphic in orientation, there are also a number ofnumerical techniques in EDA.

c© 2015- Sergio Rey Geographic Information Analysis http://sergerey.org

EDA Versus Confirmatory Analysis

Confirmatory Analysis (e.g. regression)Problem → Theory → Model → Data → Conclusion

Exploratory AnalysisProblem → Data → Analysis → Model

c© 2015- Sergio Rey Geographic Information Analysis http://sergerey.org

Outline

1 GIS and Spatial AnalysisBig PictureWhat is Spatial Analysis?

2 EDA and ESDAExploratory Data Analysis (EDA)Exploratory Spatial Data Analysis (ESDA)

c© 2015- Sergio Rey Geographic Information Analysis http://sergerey.org

What is ESDA?

DefinitionsType of EDAExtended to include spatial attributes of the data

Cross fertilizationApplying classic EDA to spatial dataDeveloping new EDA methods for spatial dataInteractions between EDA and ESDA

c© 2015- Sergio Rey Geographic Information Analysis http://sergerey.org

How does ESDA fit in spatial analysis?

Spatial Modeling?Modeling based on assumptionsESDA largely model freeMatter of degree (e.g., clustering)

Mapping?Maps play a critical role in ESDADoes a map = ESDA?No. ESDA = map, manipulation + visualization

c© 2015- Sergio Rey Geographic Information Analysis http://sergerey.org

PySAL and ESDA (Video)

c© 2015- Sergio Rey Geographic Information Analysis http://sergerey.org