A planned campaign that measures depths, detects hazards, samples the seabed and positions shoreline and aids so the results can be charted. Every sounding is tied to a horizontal position and a vertical datum, and the whole data set carries an uncertainty budget checked against a stated survey order. Jobs range from a one-day berth check by a launch to multi-season ship campaigns across a coastal approach.
Harbour master wants a hydrographic survey of berths 4 to 7 before the new tankers start calling.
Bathymetry is depth data. A hydrographic survey is depth plus everything a mariner needs: hazards, datum, uncertainty and the charting decisions that follow.
Also heard as
- hydro survey
- hydrographic surveying
Do not mix it up with
- Bathymetry: Bathymetry is only the depth measurement; a hydrographic survey adds hazards, datums, features and quality control for charting.
Related terms
Bathymetry
The measured depth and shape of the seabed, or the work of measuring it.
S-44
The international minimum standard for hydrographic surveys, setting uncertainty, detection and coverage limits by order.
Line plan
The set of pre-planned survey lines, with spacing and orientation, that a vessel follows to achieve the required coverage.
Nautical chart
A map of waters and coasts made for mariners, showing depths, hazards, aids to navigation and landmarks.