Daily Archives: February 11, 2008

1759 First statements by Lambert (France) of principles underlying photogrammetry 1839 First ever photographs by Daguerre and Nepce, in France 1840 French used photos in making topographic maps. 1850’s Photographs important in documenting exploration of the U.S. West (through 1870’s). … Continue reading →

NDVI is the acronym for normalized difference vegetation index. It is a simple formula using two satellite channels. If one band is in the visible region (VIS, for example AVHRR band 1) and one is in the near infrared (NIR, … Continue reading →

The amount of water available per person in India is decreasing steadily – from 3450 cm in 1951, it fell to 1250 cm in 1999. According to the Ministry of Water Resources is expected to decrease further to 760 cm … Continue reading →

The ozone hole is a thinning of the stratosphere’s ozone layer, which is roughly 9 to 31 miles above the earth’s surface. The depletion of the ozone is due to man-made chemicals like chlorofluorocarbons (CFCs). A thinner ozone layer lets … Continue reading →