How much of the seabed the sensors have actually seen. Bathymetric coverage of 100 percent means the swaths touch or overlap with no unmeasured gaps; 200 percent means every point is covered twice, normally by independent passes. Singlebeam surveys measure only a thin strip along each line, so features between lines can be missed. Coverage plots are checked every day so holidays are found before the boat leaves the area.
Coverage plot shows a sliver missing along the pier face, we need a slow pass tight to the fenders.
Coverage on a plot is not coverage that meets the spec: soundings rejected in cleaning, or beams outside the uncertainty limit, do not count.
Also heard as
- bottom coverage
- full coverage
Related terms
Overlap
The share of each swath that is also covered by the neighbouring line, planned in to guard against gaps.
Holiday
A gap in survey coverage where no data was collected, which must be filled before the survey is complete.
Feature detection
The ability of a survey system to find seabed objects of a stated minimum size, usually given as a cube edge length.
Infill
A short extra line run to fill a gap in coverage, usually to clear holidays found during processing.
Exclusive Order
The strictest survey order, used for berths and critical channels where under-keel clearance is minimal.