Spatial Analysis

Sergio Rey

1/24/23

Spatial Analysis


  • What is Spatial Analysis?
  • What is Exploratory Data Analysis?
  • What is Exploratory Spatial Data Analysis?

What is Spatial Analysis?

GIS Then

Snow Map

GIS Now

Crime Map

GIS Functions

Anselin-Getis (1992) Taxonomy

  • Input

  • Storage

  • Analysis

  • Output

Many other taxonomies

GIScience

Goodchild (1992)

  • cross-disciplinary

  • central role for spatial analysis

  • scientific glue

What is Spatial Analysis?

From Data to Information

  • beyond mapping

  • added value

  • transformations, manipulations and application of analytical methods to spatial (geographic data)

Locational Invariance

How Insights Change with Location

  • spatial analysis is not locationally invariant

  • the results change when the locations of the study objects change

  • where matters

State Income Distributions 1929

Relative Quintiles

State Income Distributions 1929

Income Distribution

Randomized Income Distribution 1929

Random Permutation

Randomized Income Density 1929

Income Distribution

Localtional Invariance

Locational Variance

Observed

Spatial Autocorrelation Income 1929

Moran Scatterplot

Randomized Income 1929

Moran Scatterplot (Random)

Locational Variance

Components of Spatial Analysis

  • Mapping and Geovisualization showing interesting patterns
  • Exploratory Spatial Data Analysis discovering interesting patterns
  • Spatial Modeling explaining interesting patterns

Summary: Spatial Analysis

  • Beyond Mapping
  • Central role for analysis
  • Distinguished by Locational Variance
  • Location matters

Components

  • showing
  • discovering
  • explaining

What is Exploratory Data Analysis?

Exploratory Data Analysis (EDA)

What is EDA?

EDA is an approach, not simply a set of techniques, but an attitude/philosophy about how a data analysis should be carried out.

Postpones the usual assumptions about what kind of model the data follow

Origins Tukey, J. (1977) Exploratory Data Analysis. Addison, Wesely

Components of EDA

Set of techniques to

  • maximize insight into a data set

  • uncover underlying structures

  • extract important variables

  • detect outliers and anonalies

  • test underlying assumptions

  • suggest hypotheses

  • develop parsimonious models

EDA Techniqes

Statistical Graphics

  • EDA relies heavily on statistical graphics

  • EDA is not identical to statistical graphics

  • Graphics support pattern recognition and open-minded exploration

  • Interactive graphcs push this even further

Quantitiatve Methods: Although heavily graphic in orientation, there are also a number of numerical techniques in EDA.

EDA Versus Confirmatory Analysis

Confirmatory Analysis (e.g. regression)

Problem \(\rightarrow\) Theory \(\rightarrow\) Model \(\rightarrow\) Data \(\rightarrow\) Conclusion

Exploratory Analysis

Problem \(\rightarrow\) Data \(\rightarrow\) Analysis \(\rightarrow\) Model

What is Exploratory Spatial Data Analysis?

Exploratory Spatial Data Analysis (ESDA)

Definitions

  • Type of EDA

  • Extended to include spatial attributes of the data

Crossfertilization

  • Applying classic EDA to spatial data

  • Developing new EDA methods for spatial data

  • Interactions between EDA and ESDA

How does ESDA fit in spatial analysis?

Spatial Modeling?

  • Modeling based on assumptionss

  • ESDA largely model free

  • Matter of degree (e.g., clustering)

Mapping?

  • Maps play a critical role in ESDA

  • Does a map = ESDA?

  • No. ESDA = map, manipulation + visualization

Next Up


Spatial Analysis Software