Patent ID: 8300499

Claim:
A method comprising: receiving linear downscan sonar data based on sonar returns from a series of fan-shaped beams produced sequentially by a linear downscan transducer mounted on a watercraft, the series of fan-shaped beams insonifying different fan-shaped regions of an underwater environment beneath the watercraft as the watercraft travels; receiving conical downscan sonar data based on sonar returns from a generally conical beam produced by a second downscan transducer, wherein the conical beam is wider than each fan-shaped beam in a direction parallel to a longitudinal length of the linear downscan transducer; combining the linear downscan sonar data and the conical downscan sonar data to produce combined downscan sonar data; and rendering the combined downscan sonar data as at least one image on a display, the at least one image including a composite of images of the fan-shaped regions arranged in a progressive order corresponding to the travel of the watercraft.