Maps and the Geospatial Revolution

Lesson 4 – Lecture 1

Anthony C. Robinson, Ph.D Lead Faculty for Online Geospatial Education John A. Dutton e-Education Institute Assistant Director, GeoVISTA Center Department of Geography The Pennsylvania State University

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Doing Spatial Analysis

• Once you have spatial data, you should do something with it

• Simply showing that you know something exists in a place isn’t enough

• Geographic science uses a wide range of analytical techniques to take measurements, make comparisons, and detect anomalies

Overlay (and Beyond)

• Overlay

– The most basic spatial analysis method

– Put this on top of that and see what happens

– Proposed by Ian McHarg in Design with Nature (1969)

• Buffering

– Identifies areas of interest around a location based on distance or time

Buffering

Surface Analysis

• Surface Analysis and Interpolation

– When you have lots of individual observations and you want to make an overall map that shows trends

– Temperature readings from towns scattered across a state

– Interpolation is necessary to make estimates where you have gaps in coverage

• These types of maps are frequently called “heat maps”

– They should be called density surface maps, but whatever

Surface Interpolation

Cluster Detection

• A cluster is a spatial pattern that appears distinct from expected geographic variation

– 10 White Minivans at the supermarket = not

unexpected

– 10 White Minivans in the same driveway = possible cluster

• Most famous example is John Snow’s map of a

Cholera outbreak in London

Maps and the Geospatial Revolution www.coursera.org/course/maps Twitter @MapRevolution Online Geospatial Education @ Penn State www.pennstategis.com

This content is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported License