Remote Sensing Legends & Misconceptions

#1) Satellite Images are the same as digital photos:
More Accurately... Typically, there aren't any cameras on satellites taking pictures of Earth. Remote sensing devices on modern weather satellites are active instruments called radiometers that measure radiation in discrete intervals with scanning mirrors that reflect digital data back to the satellite to be transmitted down to earth for processing. Early satellites in the 1960s used passive camera systems and astronauts onboard the space shuttle have taken numerous photographs using hand-held cameras, however, satellite images have been produced by radiometers since the 1970s.

#2) The Blue Marble picture of Earth taken by the crew of Apollo 17 was the first full view of the planet.
More Accurately... Though widely celebrated and historically renown, the Blue Marble picture taken in 1972 by a hand-held camera was five years later than the first full disk picture of Earth taken by cameras on NASA's ATS-III satellite.

#3)The spatial resolution of an image indicates the size of a feature discernable in that image.
More Accurately... While it's true that each pixel in an image with 30-meter resolution represents a square area of 30 meters by 30 meters on the ground, sometimes features larger than 30 meters may not be discernable and very often features much smaller than 30 meters will be easy to identify, especially if you're already familiar with the area captured by the image. For example, narrow trails of only 1 or 2 meters in width are easily discernable in dense forests in images with 30-meter pixel resolution because of the contrast between the bright soil and dark forest. Alternatively, a 30-meter plot of pines trees could be indistinguishable from neighboring deciduous trees in the same image. There simply isn't a direct correlation between the units of spatial resolution and the size a features you'll be able to see in that image.