lawnmower survey
n.— «Over a 20-hour mission the team surveys 5km x 4km sections by running the AUV up and down, building up about 15 overlapping swaths of sonar data in a process known as a lawnmower survey. The multi-beam sonar produces 111 beams of sound at right angles to the AUV’s path, each taking a depth measurement, which are put together to build up a picture of the ocean floor.» —“Drop in the ocean” The Engineer (London, United Kingdom) Sept. 16, 2008. (source: Double-Tongued Dictionary)