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Despite their economic, cultural, and aesthetic value, our nation's coastal areas
and marshlands are in serious decline. Since the late 1700s, over half
the wetlands in the lower 48 states have disappeared. These losses impact
fisheries such as the Chesapeake Bay oyster harvest, which has plummeted
from 25 to 1 million pounds per year. Consequently, coastal and wetlands
habitat restoration is becoming a national priority.
As a component of NOAA's National Ocean Service, the National Geodetic
Survey is contributing remote sensing and geodetic surveying technologies
at a number of restoration sites. Orthorectified aerial photography shows
site characteristics, differential leveling and static GPS to provide accurate
positions and tidal datums to project site, and RTK surveys create digital
elevation models of the wetland surface.
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