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Case study:  Coastal imagery at ultra-high resolution (2cm GSD) for mapping marine debris 

The Challenge

  • The Hawai'i Department of Land and Natural Resources needed to identify the locations, type and size of marine debris accumulating along the shorelines. Mapping marine debris is important for effective planning for removal to prevent further threat or impact to the coastal environment.

  • Accessibility can be difficult depending on shoreline terrain, so ground-based efforts can take considerable effort and time.

  • Previous approaches to marine debris monitoring have relied on costly, unreliable and inconsistent methods such as in-air observations from a helicopter or oblique angle aerial photography. There is no standard method for shoreline aerial surveys, yet there is an urgent need for a consisent, structured method for coastal monitoring.


RMH Solution 

  • RMH collected aerial ultra high imagery of the coastlines of the main 8 Hawaiian islands, with a target GSD of 2cm and covering a swath of 300m. The images were then processed into full scale orthomosaics. .



  • The orthomosaics of the shorelines have been analyzed in GIS by staff of the Hawai'i Coral Reef Initiative at the University of Hawai'i at Manoa. They have created maps of marine debris hotspots and generated data to assist efforts for removal throughout the state of Hawai'i.

  • Thanks to the generous support of the Government of Japan and the North Pacific Marine Science Organization (PICES) as well as technical assistance from ESRI, this shoreline imagery will be made publicly available for other coastal resource management applications on the state of Hawai'i Office of Planning's open GIS data portal by the summer of 2016.


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