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Ebb-tidal delta at Raglan Bar on New Zealand’s North Island

By Coastal and Marine Hazards and Resources Program
Map of seafloor depth at coast. Yellow (shallow) lobe extends left into blue (deep) water. Many small arrows on yellow lobe.
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Detailed Description

Arrows show average migration of sand bars over 5 years in the ebb-tidal delta at Raglan Bar on New Zealand’s North Island. Scientists produced the map by analyzing “time-averaged images” derived from video collected from 2010 to 2015. A time-averaged image is made by averaging light intensities recorded at each pixel in each frame of a video; see example. (Figure 10a in 2017 Marine Geology paper)

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