The document discusses spatial analysis techniques in geographic science, emphasizing the importance of analyzing spatial data beyond merely identifying its existence. It covers methods such as overlay, buffering, surface analysis, and cluster detection, with examples like John Snow's cholera outbreak map illustrating the application of these techniques. The lesson highlights the need for effective analysis to uncover meaningful insights from spatial data.

1. Maps and the Geospatial Revolution
Lesson 4 – Lecture 1
Anthony C. Robinson, Ph.D
Lead Faculty for Online Geospatial Education
JohnA. Dutton e-Education Institute
Assistant Director, GeoVISTA Center
Department of Geography
The Pennsylvania State University
This content is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported License

2. 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

3. 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

4. Buffering

5. 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

6. Surface Interpolation

7. 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

8. 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