Survey tracklines delineate the line along which the vessel travelled as it was surveying. The vessel collects multibeam echosounder data (MBES) by emitting a fan of soundwaves and recording the reflected signal. The area of seabed ensonified is known as the footprint and the area surveyed along a transect is commonly called the swath. The size of the footprint depends on the depth: deeper areas will have a larger footprint than shallower areas. The central line of the swath is the trackline and so therefore, tracklines in shallower water will be closer together than those in deeper water. Suggested Citation: Furey, T; Sacchetti, F. (2023). INFOMAR Seabed Survey Trackline. Marine Institute, Ireland. https://doi.org/10/mhpx