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Vanishing valleys and misleading maps: why the world is now a different shape   Have you ever spotted this shape on world maps? You will now ... It’s a sheer sided valley in the Sudan 3 x 3 degrees across and over 150 m deep ! Fly over it with the ERS-1 altimeter and you only see flat desert. Comparing the GDEMs with the altimeter heights shows that the whole feature does not exist.
Images: DEM team at De Montfort university, Leicester(PI: Philippa Berry)  A series of spectacular waterfalls in the Amazon basin cascade over undiscovered cliffs over 2000 km long! (left image, GDEM data) The altimeter map (right) shows the real Amazon, with its intricate network of interlocking rivers and tributary streams … but no amazing cliffs! Images: DEM team at De Montfort university, Leicester.  The Great Wall of the Western Sahara - a 200 m high "wall" runs for over 200 km across the western Sahara, where DCW and DTED meet. This is caused by a 200 m contour interval in the DCW data. The altimeter shows the actual surface. Images: DEM team at De Montfort university, Leicester. Release date: 2 July 2002 |