Latitude and Longitude: A Global Address

In this exceptionally clear and well thought-out program, viewers learn that longitude and latitude can be used to fix any point on earth: the lines of latitude (north-south) and lines of longitude (east-west) form a grid with coordinates that allow navigation to a specific place by air, land or sea. After explaining how longitude and latitude work, the program looks at the evolution of this navigational methodology over history, from the early experiments of the Greeks Erathosthenes and Ptolemy up to the invention of the chronometer by John Harrison in the 18th century (chronicled in Dava Sobel's best-selling book Longitude). In addition, the video explains the importance of latitude-longitude measurements in helping to define climatic forces, and shows the great precision of Global Positioning Satellites in finding locations anywhere on earth. A fine resource for geography, world history and earth science classes, this is recommended. Aud: J, H, C, P. (S. Fisher)