Tuesday, 24 June 2014

Get to know a projection...

http://www.wired.com/2014/06/get-to-know-a-projection-the-space-oblique-mercator/

Coincidentally, I've just finished pulling together a lecture which includes projections when this happened to catch my eye.  Without John Parr Snyder, Landsat (a remote sensing satellite taking continuous images of the Earth's surface) would just be pretty pictures - as opposed to a real mechanism to map land cover change.  Because Landsat records the 3D surface of the Earth as a 2D image, it needs some means of understanding where each part of that image is located on the Earth.  Every 2D representation will have some distortion (don't believe me? Try peeling an orange and using the peel to prefect represent the 3D orange as a flat surface sometime!).  Knowing what that distortion is means that we can match up each image to where it should be on the Earth and with other images.

Snyder’s Space-Oblique Projection

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