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Using spatial reference systems created by geodesists, any location on the Earth can be located quickly and accurately. Click
on the image for an animated view.
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Geodesy is the science of measuring and monitoring
the size and shape of the Earth. Geodesists basically
assign addresses to points all over the Earth. If you were to stick
pins in a model of the Earth and then give each of those pins an address,
then you would be doing what a geodesist does. By looking at the height,
angles, and distances between these locations, geodesists create a spatial
reference system that everyone can use.
Building roads and bridges, conducting land
surveys, and making maps are some of the important activities that depend
on a spatial reference system. For example, if you build a bridge, you
need to know where to start on both sides of the river. If you don't,
your bridge may not meet in the middle.
As positioning and navigation have become fundamental
to the functions of society, geodesy has become increasingly important.
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The earth's crust is made of up separate plates that ride atop a sea of magma. These plates are constantly shifting and interacting. Click
on the image for
an animated view. |
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Geodesy helps the transportation industry ensure
safety and reliability, while reducing costs. Without
geodesy, planes might land next to -- rather than
at -- airports, and ships could crash onto land.
Geodesy also helps shipping companies save time
and money by shortening their ships' and airplanes'
routes and reducing fuel consumption.
Geologists, oceanographers, meteorologists, and even paleontologists use geodesy
to understand physical processes on, above, and within the Earth. Because geodesy
makes extremely accurate measurements (to the centimeter level), scientists can
use its results to determine exactly how much the Earth's surface has changed
over very short and very long periods of time (Careers in Geodesy, 1986).
The Earth's surface changes for many reasons. For instance, its surface rises
and falls about 30 centimeters (about 1 foot) every day due to the gravitational
influences of the moon and the sun. The Earth's outermost layer, the crust,
is made up of a dozen or more "plates" that ride atop a sea of molten rock,
called magma, which flows beneath the surface of the Earth.
Plate tectonics is the scientific discipline that looks at how these plates
shift and interact, especially in relation to earthquakes and volcanoes. Although
these phenomena are violent and usually affect large areas of land, even smaller
events, such as erosion and storms, have an impact on shaping the Earth's surface.
Geodesy helps us determine exactly where and how much the Earth's surface is
changing.
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