Maps and the Geospatial Revolution: Lesson 2, Lecture 2

Maps and the Geospatial Revolution

Lesson 2 – Lecture 2

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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Spatial Relationships

• You need some ground rules to establish what is possible when it comes to spatial relationships

• Spatial Topology

– The set of relationships that spatial features can have with one another

• Let’s consider how people relate to each other in

space

Spatial Relationships

• Equals – When we first met each

other, we felt like we were “one.”

• Touches

– Our first kiss was gentle – no tongue.

• Overlaps

– During our honeymoon we… <deleted>

• Contains

– For 9 months the baby was inside (and much quieter).

Spatial Relationships

• Disjoint

– Later on, we got sick of each other and watched TV from opposite sides of the room.

• Covers

– The dog sleeps on top of me, creating a huge amount of heat.

• Crosses

– Although we both know how to find our way home from the grocery store, the only routing point we have in common is our driveway.

Spatial Relationships

• What would happen if we ignored them?

– Things like Mapquest and Google Maps would never be able to do anything useful

• For example

– Consider 500 road segments that encompass

your neighborhood and nearby region

Scale

• Two key concepts of scale are used in Geography

• Map scale

– Ratio of the distance on the map to the real distance on the Earth

– Large scale = 1/1000 Small scale = 1/10,000,000

• Scale of analysis

– The specific geographic context used to understand a problem

– Neighborhood, County, State, Country, Continent

What About Time?

• Spatial Relationships and Scale are really important, but what would they mean without considering Time?

• Almost everything Geographic involves a dynamic process of one type or another

• Maps often make it hard to see time as an explicit factor

What About Time?

What About Time?

What About Time?

Part of the image is from 2012 from one sensor, and the other part is from 2013 from another sensor.

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

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