Marine sediment classification using sidescan sonar and geographical information system software in Kaneohe Bay, Oahu, Hawaii

The distribution of sediment types in the south section of Kaneohe Bay was surveyed using Datasonics SIS 1502 sidescan sonar interfaced to GeoDAS (Geographical Data Acquisition System). The GIS (Geographic Information Systems) software, ERmapper, was used to classify the digital sidescan image based on color differences using an unsupervised classification technique. Sediment samples were taken from the study area and analyzed for grain size distribution to verify the use of ERmapper as a classification tool. The imagery clearly revealed different sediment properties. These differences were also distinguished by the unsupervised classification process. The authors were not able to process a sufficient number of sediment samples to allow for a statistical comparison of sediment grain size distribution and the sidescan image. However, the sediment size distribution observed in the samples they analyzed showed a clear relationship to the sidescan image. This analysis therefore indicates that the use of sidescan sonar coupled with GIS software, has the potential to be used to remotely characterize sediment types within the coastal zone.