Sideimaging

Sideimaging is a type of sonar technology used in marine electronics to create high-resolution images of the water and seabed to the left and right of a vessel. It differs from traditional downward-looking sonar by sweeping wide, oblique beams toward the port and starboard sides, producing a broad horizontal view of features such as contours, structures, vegetation, and fish schools along the hull’s wake.

In operation, sideimaging systems deploy transducers arranged to emit multiple angled beams to the sides. The returned echoes are processed to form a two-dimensional image with depth vertical scale and a wide horizontal swath. Frequencies commonly used range from mid to high bands, and performance improves with water clarity and moderate depths. The technology is commonly integrated with GPS and mapping to geolocate features and create bathymetric or habitat maps.

History and development: side imaging gained prominence in the early 2000s as consumer and professional fish-finding systems expanded beyond traditional downward sonar. Brands such as Humminbird popularized marketed versions, increasingly combining side imaging with CHIRP technology, higher resolutions, and more sophisticated interpretation tools. Over time, it has become a standard feature in many marine electronics lineups.

Applications and limitations: sideimaging is widely used for fishing, navigation, and underwater mapping, enabling rapid surveys of bottom structure, weed lines, and submerged objects over large areas. Limitations include reduced effectiveness in very deep water, sediments that scatter sound, and the need for motion to build a coherent image. Accurate interpretation requires practice, as appearances can be influenced by bottom type and water conditions. See also side-scan sonar and down-imaging.