1Hydrography
measurement and description of the physical features of oceans, seas, coasts, lakes, and rivers, including the prediction of how they change over time.
2support safe and efficient navigation
Primary purpose of hydrography
3Bathymetry
measurement and representation of underwater depths and the shape of the seabed.
4Navigable depth
depth sufficient for safe vessel operation.
5Least depth
minimum depth found within a surveyed area or feature.
6Hazard
underwater feature or obstruction that may threaten navigation.
7Under-keel clearance
vertical distance between the bottom of a vessel and the seabed.
8Seabed
bottom surface of a body of water.
9Measure
collect observations and measurements in the survey area.
10Reference
establish the coordinate systems and reference levels for the measurements.
11Process
correct, organize, and analyze the collected data.
12Represent
present the results through maps, charts, surfaces, and other products.
13Decide
use the resulting information to support navigation, engineering, planning, and management.
14Integration
turns observations into usable evidence.
15Accuracy
closeness of measurements to the true value.
16Completeness
sufficient coverage and information to meet the survey purpose.
17Currency
information is up-to-date and reflects current conditions.
18Clear metadata
information describing how the data was collected and processed.
191. Chart navigable depth
2. Support port access
3. Locate hazards
4. Keep information current
Navigation and Maritime Safety
201. Coastal infrastructure
2. Environmental management
3. Disaster risk reduction
4. Maritime jurisdiction
5. Blue economy and tourism
6. Science and modelling
Applications of Hydrography
21Geodesy and positioning
determines the location and coordinates of survey measurements.
22Water levels and physical oceanography
deals with tides, water levels, currents, and other water conditions.
23Acoustic depth measurement
uses acoustic techniques to determine water depths.
24Seabed and sub-bottom interpretation
determines the character and structure of the seabed and the material beneath it.
25Cartographic communication
transforms survey data into maps, charts, and other understandable products.
26Mariner / Port authority
Nautical charts, least depths, and hazard information
27Engineer / Contractor
Bathymetric surfaces, cross-sections, and volume calculations
28Coastal planner / DRRM office
Terrain-bathymetry models and shoreline-change information
29Environmental manager
Seabed-character, habitat, and change layers
30Researcher / Modeler
Quality-controlled depths and metadata
31Horizontal datum
reference system used for horizontal positioning.
32Vertical datum
reference surface used for measuring elevations or depths.
33Metadata
information describing the data, including its source, collection, processing, and quality.
34Bathymetric surface
representation of underwater terrain based on depth measurements.
35Underwater terrain
the shape and elevation of the submerged ground, represented using bathymetric data.