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In April 2004, Fugro Pelagos used airborne Lidar technology to map
the entirety of the Southern California coastline from the Mexican
border to Long Beach. This project took place between April 10 -
18 for the purpose of obtaining existing bathymetric and topographic
conditions of the entire coastline, including the jetties and navigation
channel at the entrance to Mission Bay.
This survey provided bathymetric and topographic Lidar
data from the cliff base across the beach to approximately the 10
meter contour. About 3,600 line km covering approximately 200 km
of coastline were surveyed in only nine days (including re-flights
for fill-in). Collectively, the surveys covered an area of approximately
434 square kilometers. In such shallow water, a multibeam survey of this size
could take as long as 85 days, without ever getting the additional
topographic information on the beach.
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For
the beach areas, bathymetric Lidar data were collected at a 4 x 4 m sounding
density, flying at an altitude of 300 m, while topographic data were acquired
at a 2 x 1 m spot density flying at an altitude of 430 m. For the entrance
to Mission Bay, bathymetric Lidar data were collected at a 2 x 2 m sounding
density, flying at an altitude of 300 m, while topographic data were acquired
at a 2 x 0.7 m spot density also flying at an altitude of 300 m. The surveys
were scheduled such that topographic Lidar data were collected at low
water and bathymetric Lidar data were collected at high water. This provided
the maximum data overlap at the land / sea interface and also minimized
the potential for data gaps as a result of breaking waves within the surf
zone.
Much of the Lidar data and digital aerial photography collected
during this survey will complement acoustic multibeam bathymetry, acoustic
multibeam backscatter imagery and digital multispectral data collected
by Fugro Pelagos previously from Mexico to Dana Point and will be used
by San Diego Association of Governments (SANDAG) to form a regional planning
database.
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