Maps and the Geospatial Revolution

Lesson 3 – 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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Where are we now?

• Locating things used to be very difficult, and it was done using time-intensive methods that weren’t very accurate

• You probably associate location technology with GPS –

– Global Positioning System, built by the U.S. military starting in the 1970’s

– Not invented by Apple or Google, believe it or not

• GPS is one example of a Global Navigation Satellite System (GNSS)

– Others include the Russian GLONASS and EU Galileo system

Where are we now?

• It’s already common for consumer devices to use GNSS to derive locations

– Often augmented with wifi hotspots and other signals

that combined can improve accuracy and coverage

• Consumer-grade stuff can locate positions to within a few meters, but they can be off by hundreds of meters in poor conditions

• Professional systems are used for surveying property lines and other serious geo-tasks

Where are we now?

• A GPS-enabled device can give you a point location defined by latitude and longitude coordinates

– My desk at home is 40.77004, 77.896744

• If I walked around my yard collecting multiple points, I could

create a polygon that represents the property I own

• If I collected points in a row between my couch and the fridge, I’d have a line feature

• Points, lines, and polygons are the primary forms of spatial vector data

The Earth from Above

• Virtual globe tools like Google Earth have made images of the Earth easily accessible

• Most geographic image data comes from satellites and airborne sensors, but you can even make your own DIY Drone now

• Geographic image data is raster data, which captures information by assigning values to cells in a grid

The Earth from Above

• The size of raster grid cells determines how much resolution you have for the image

The Earth from Above

• The science and technology associated with imaging the Earth is called Remote Sensing

• It’s not just photographs – it can involve the use of lasers (LIDAR) and infrared sensors

The Earth from Above

Source: Science@NASA: http://science.nasa.gov/science-news/science-at-nasa/2011/16may_groundtracks/

Source: USGS: http://coastal.er.usgs.gov/hurricanes/sandy/lidar/

Source: USGS: http://coastal.er.usgs.gov/hurricanes/sandy/lidar/

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

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