Side Imaging

Category: Electronics

Side imaging (also called StructureScan on Lowrance units or MEGA Side Imaging on Humminbird) is a sonar technology that projects a thin, wide sonar beam to the left and right of the boat, creating a detailed, almost photographic image of the bottom and structure out to 100-200 feet on each side. Side imaging revolutionized fishing by allowing anglers to scan large areas quickly from a single pass, identifying structure (stumps, brush piles, rock formations, creek channels), bottom composition transitions, and individual fish that would be invisible to traditional 2D sonar. The key to reading side imaging is understanding shadows: objects projecting up from the bottom cast a sonar shadow behind them (relative to the transducer), and the height of the shadow indicates the height of the object. Fish appear as bright dots or elongated marks on the scan, often positioned near structure. Side imaging is best used while the boat is moving at moderate speed (3-6 mph) in a search pattern, scanning for structure and fish-holding areas that can then be investigated more closely with other sonar technologies or targeted casts. The effective range decreases with depth — in shallow water (under 15 feet), side imaging provides incredibly detailed views; in deep water (over 40 feet), range and detail are reduced.