Understanding the Four Basic Types of Analysis

Paul Trevillion - Esri

Michael Sarhan - Esri

What are the four basic types of analysis?

• Proximity

• Overlay

• Statistical

• Temporal

Michael Sarhan

Proximity

What is proximity analysis?

Buffer zones around a schoolBuffer zones around a school

How do ArcGIS tools measure proximity?

Euclidean distanceGeodesic Least-cost path

Categories of Proximity Analysis

• Area Expanding

• Numeric value

• Linear Measure

Paul Trevillion

Proximity Demo

Paul Trevillion

Overlay

Vector Overlay

Which Schools have the most incidents crime

nearby?

Overlay techniques

OR

Union

Identity

Intersect

Apportioning attributes

Before splitBefore split

dfbdfbdfb100100 100

Without ratio policyWithout ratio policy

100

100

100

100

100

100

With ratio policyWith ratio policy

70 3050

30 50 70

Raster Overlay

Michael Sarhan

Overlay Demo

Michael Sarhan

Statistical Analysis

Types of Statistical Analysis

Descriptive Statistics Inferential Statistics

Percent of Total Crimes by Ward in the District of Columbia Hot Spot Analysis weighted on Violent crime in the District of Columbia

Descriptive Statistics

Mean CenterMean center

total crime by Quarter CY 2014

Mean center total crime by

Quarter CY 2014

Descriptive Statistics

Standard Deviational

Ellipses

Working with data distributions

• Normal and statistically significant distributions

Normal distributionNormal distribution

Standard deviation

Inferential Statistics

Average Nearest Neighbor SummaryAverage Nearest

Neighbor Summary

The Average Nearest Neighbor tool

Dengue fever casesand households

Dengue fever casesand households

Inferential Statistics

• Measures distribution of features and attribute values

Spatial Autocorrelation

Report

Spatial Autocorrelation

Report

The Spatial Autocorrelation tool

Inferential Statistics

Hot spot analysis

Paul Trevillion

Statistics Demo

Paul Trevillion

Temporal Analysis

What is temporal analysis?

Spatial VariancepH levels measured and analyzed for entire reservoir on same day

Spatial VariancepH levels measured and analyzed for entire reservoir on same day

Temporal VariancepH levels measured and

analyzed at one location each year

Temporal VariancepH levels measured and

analyzed at one location each year

7.0

6.9 7.1

7.0

6.8

7.0

6.7 6.7

6.9

2009 – 6.62010 – 6.72011 – 6.8

Incorporating time in your analysis

Political violence in Somalia 1997-2011

Temporal patterns and spatial statistics

1969 1985 2002

Space-time analysis vs. time snapshots

Michael Sarhan

Temporal Demo