Mapping Coral Reef Benthos, Substrates, and Bathymetry, Using Compact Airborne Spectrographic Imager (CASI) Data

Remote Sensing

Ian A. Leiper¹  Stuart R. Phinn¹  Chris M. Roelfsema¹  Karen E. Joyce¹ 

[1] Centre for Spatial Environmental Research, School of Geography, Planning and Environmental Management, University of Queensland, St Lucia, QLD 4072, Australia; E-Mails:

关键词: coral reef;    remote sensing;    hyperspectral;    CASI;    spectral angle mapper;   

DOI  :  10.3390/rs6076423

来源: mdpi

【 摘 要 】

This study used a reef-up approach to map coral reef benthos, substrates and bathymetry, with high spatial resolution hyperspectral image data. It investigated a physics-based inversion method for mapping coral reef benthos and substrates using readily available software: Hydrolight and ENVI. Compact Airborne Spectrographic Imager (CASI) data were acquired over Heron Reef in July 2002. The spectral reflectance of coral reef benthos and substrate types were measured in-situ, and using the HydroLight 4.2 radiative transfer model a spectral reflectance library of subsurface reflectance was simulated using water column depths from 0.5–10.0 m at 0.5 m intervals. Using the Spectral Angle Mapper algorithm, sediment, benthic micro-algae, algal turf, crustose coralline algae, macro-algae, and live coral were mapped with an overall accuracy of 65% to a depth of around 8.0 m; in waters deeper than 8.0 m the match between the classified image and field validation data was poor. Qualitative validation of the maps showed accurate mapping of areas dominated by sediment, benthic micro-algae, algal turf, live coral, and macro-algae. A bathymetric map was produced for water column depths 0.5–10.0 m, at 0.5 m intervals, and showed high correspondence with in-situ sonar data (R² value of 0.93).

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland