Maps and the Geospatial Revolution: Lesson 3, Lecture 1
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The document discusses the evolution of location technology, focusing on the development and impact of GPS and other global navigation satellite systems (GNSS). It highlights the accuracy of consumer devices in determining locations and introduces concepts of spatial vector data and raster data in geographic imaging. Additionally, it mentions the significance of remote sensing technology in capturing Earth imagery.
Maps and the Geospatial Revolution: Lesson 3, Lecture 1
- 1. 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 This content is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported License
- 2. 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
- 3. 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
- 4. 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
- 5. 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
- 6. The Earth from Above • The size of raster grid cells determines how much resolution you have for the image
- 7. 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
- 8. The Earth from Above Source: Science@NASA: http://science.nasa.gov/science-news/science-at-nasa/2011/16may_groundtracks/
- 11. 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