Lassoo!: an interactive graphical tool for seafloor classification

Lassoo! is an interactive graphical tool that facilitates the empirical classification of seafloor materials. Lassoo! can: (1) input a multivariate geo-referenced data set (e.g. geophysical properties, acoustic data or acoustic derivative data sets); (2) display data in geo-referenced map space and/or in multivariate data space (e.g. side scan sonar imagery data in geo-referenced space and parameters derived from the imagery in bivariate space); (3) interactively select subsets of data points in either bivariate or geo-referenced spaces; (4) assign “classes” to selected regions in either data space and; (5) automatically identify these “classes” in both data spaces, Lassoo! has been used for the evaluation of data collected with the commercial sediment classification system “RoxAnn” in an area of seafloor dredge spoil dumping, The RoxAnn data were evaluated by direct comparison with side scan sonar data obtained with a Simrad EM1000 multibeam system. The purpose of the project was to monitor the dispersal of sediments from two dump sites in the survey area and to classify the various sediments encountered in this region. The results of acoustic classification of the sediments were compared to ground truth data obtained from cores. It was observed that the ability to select classes in one space and the identification of these classes in other spaces is a powerful tool for enhancing the quality of empirical sediment classification