Case Studies Environmental Projects


Water Pollution – Hong Kong Open Seas


Objective of the Project:
In August 2012 a container vessel was lost in heavy seas during a typhoon in Hong Kong waters some containers contained small plastic pellets. During the next weeks, the containers got damaged and water and beaches in lama Island and Lantau were polluted by the pellets. Dimap was engaged by the HK Marine Department to map the distribution of the pellets by an airborne operation.

Technical Solution:
In a one-day operation using the Eurocopter of the Government flying service the waters south of Hong Kong were scanned with VNIR hyperspectral (400 to 1000nm) with a spatial resolution of 1m. Data collected were fast-tracked orthorectified and compared against laboratory spectra established in the Dimap Hyperspectral Laboratory. Anomaly detection and ACE Spectral Analysis allowed the detection of pellets in different scenarios.

The collected hyperspectral data allowed the mapping of pellets in the sea area within a short time and were provided for the marine department for further action and clean up.



Figure 5: Top – Pellets on the laboratory table, spectra recorded in the laboratory (green shows the pellets) with a typical signature. Bottom left – results of fast anomaly detection showing areas with pellets in deeper water. Bottom right – pellets concentrated in a bay using ACE.


All copyrights with Dimap – 2014


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