The shared strip between adjacent swaths, usually expressed as a percentage of swath width. Multibeam surveys often plan 10 to 25 percent overlap so outer-beam noise can be trimmed and small steering errors do not open gaps. Side-scan surveys built for 200 percent coverage set line spacing equal to the range scale, so adjacent swaths overlap by half and every point is imaged twice. Overlap also gives a quick quality check, because adjacent lines should agree in the shared strip.
Bump the overlap to 25 percent over the rocky stuff, the outer beams are getting chewed up.
Also heard as
- sidelap
- swath overlap
Related terms
Swath
The strip of seabed measured or imaged across the track on one line of a multibeam or side-scan survey.
Coverage
The portion of the seabed actually measured or imaged by a survey, expressed as a percentage of the area.
Line plan
The set of pre-planned survey lines, with spacing and orientation, that a vessel follows to achieve the required coverage.
Holiday
A gap in survey coverage where no data was collected, which must be filled before the survey is complete.