I use a Lowrance HDS Pro sonar to collect environmental data (variables) for my ecological survey. Beside some basic data it would be useful to involve the bottom composition data, distinguishing the different (e.g. muddy, sandy, gravel or rip-rap) sediment types of the longitudinal sampling sites. However, the 'returns range' either PeakSV, E1 or E2 seem rather refer to the depth than the quality of bottom. How returns range values can refer to sediment type? Is it possible to use returns range values or any other data to develop - at least a relative - variable, which can refer to the composition of the waterbed at the sampling site?