Basically, remote sensing
means measuring some property of an object without actually touching it. Usually, we add some
interpretation to this measurement to draw conclusions about the object we are sensing.
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These brown trees are infected with
Pine Wilt Disease, caused by a parasitic nematode. Photo courtesy of the Kansas Department of Agriculture.
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For example, our eyes and ears are remote sensing instruments, and in fact humans
are all skilled remote sensors. Let's say you are standing in your living room,
looking at a plant in the garden. One of the important properties you can see is
the color of the plant. If the leaves are green, you can conclude that the plant is
healthy. If it's yellow, you might guess that the plant is sick or needs water. A
brown color tells you that the plant is dead. So without actually touching or
directly measuring the plant itself, your eyes can detect the color of the leaves.
Your brain, based on past experience, interprets the color to "tell" something about
its state of health.
Question: Let's take another example. How can you tell if the burner on an
electric stove is hot, without touching the surface and burning your hand? There
are actually two ways that you use remote sensing to tell whether the burner is cool
or hot. The first way is to look at the color of the burner. If it is red, you can
interpret that color to mean that the burner is very hot. But if the color is black,
the stove still may be quite hot. What other sense can you use to detect if the
burner is warm?
Click here for the answer.
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