Follow the Map

 “If you want to build a ship, don’t drum up people to collect wood and don’t assign them tasks and work, but rather teach them to long for the endless immensity of the sea.”

Antoine de Saint-Exupery

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Ptolemy’s Almagest has been on the scientist’s best sellers list for centuries.  But that wasn’t his only success. Ptolemy’s other best seller was called simply, Geography. And that is the only thing simple about it!

Geography was the first time anyone had ever presented the world with a detailed mathematical explanation for calculating lines of longitude and latitude.  Ptolemy had a gift for amalgamating the cumulative knowledge of the ancient world into a systematic layout and design.   He built on the work of Hipparchus and drew on the compilation of the known sailing directions, called periplus, collected from sailors far and wide. The Periplus of the Eritrean Sea, written in the first century by a Greek merchant living in Alexandria, provided invaluable data on the trading routes as far east as India.  

Ptolemy’s greatest innovation was to record longitudes and latitudes in degrees for 8,000 locations on his world map, the first of its kind. He developed two ways of drawing grid lines on flat maps to signify the lines of longitude and latitude on the curved surface of the globe.  In hindsight, there were many inaccuracies, such as the equator being too far north and Asia stretching too far to the east.  Yet, it was the standard for over 1,300 years. Christopher Columbus was inspired by Ptolemy’s view of the world when he set sail for Asia and unexpectedly bumped into America. There are always surprises along the way.

“As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas, and land on barbarous coasts.” 

 Herman Melville, Moby-Dick

16 thoughts on “Follow the Map

  1. I find it interesting that these great men built on the knowledge of those who had found earlier facts. Perhaps that is the answer to part of their successes. Building rather than competing.

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  2. my degree is geography (Human) so this is right up my street – and in the RAF we use navigation (which I have taught at the simplest level) so this is very interesting – I only knew of Ptolemy from Cleopatra – so thanks

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    • I am learning as I go along! I confess that science was/is not my forte, but I am finding the stories a powerful affirmation of human endeavors. Thank you so much for your comments.

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  3. Dear Rebecca,
    I just want to tell you that I have written my ideas about your dream.
    Ptolomäus invented a system of the order of space by projection a geometrical model on the globe. Without his system we would go lost in space (like I often go lost in translation).
    Here the night begins and Dina and me close our Computers.
    All the best.
    Love
    Klausbernd🙂

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