Ningaloo Reef: high resolution mapping achieved with hyperspectral, remotely-sensed data
Kobryn, H., Wouters, K., Beckley, L. and Heege, T. (2012) Ningaloo Reef: high resolution mapping achieved with hyperspectral, remotely-sensed data. In: 12th International Coral Reef Symposium, 9 - 13 July, Cairns, Australia.
Effective management and monitoring of coral reef systems requires detailed baseline data about the distribution of marine habitats. Reefs with clear waters and complex geomorphology, such as Ningaloo Reef in Western Australia, naturally lend themselves to the application of optical remote sensing as a means of gathering information about benthic habitats, bathymetry, and adjacent coastal environments. Using HyMap hyperspectral data with 3.5m pixel resolution, we were able to retrieve very detailed information about the shallow water habitats of Ningaloo Reef (down to 20m depth). This large airborne survey was processed as mosaics of bottom reflectance data using all available spectral bands (up to 21) as well as 1st and 2nd derivatives. Data products include hierarchical thematic classification with up to 46 benthic cover classes as well as per-class probability and an objected-oriented classification which combined benthic classes, depth, slope, and aspect. From these, we established that over 50% of the substrate cover was composed of algae, and hard and soft coral cover made up 7% of the study area. The majority of the corals were a mix of different densities or morphologies of Acropora and 52% (875 ha) of the coral cover was located within the sanctuary zones of Ningaloo Marine Park. Through the use of operational pre-processing of the data and a semi-automatic image classification approach, we created seamless high resolution baseline maps for 3400 km2 of the Ningaloo region, which are particularly suitable for ongoing monitoring and management.
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|Murdoch Affiliation:||School of Environmental Science|
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