Sea depth
Sea depth is bathymetry for coastal and offshore areas: how deep the water is where you are planning a quay, a subsea cable, aquaculture, infill or a jetty. The data comes as depth contours or high-resolution raster surfaces and is central to coastal zone planning and marine acquisition.
The national authority is Kartverket Sjødivisjonen (the hydrographic service) in Stavanger, which produces the depth data behind the official Norwegian nautical charts. Surveys are carried out with multibeam echo sounders from Kartverket's vessels MS Lomvi and MS Hydrograf, and the data is published as electronic nautical charts in ENC format, paper charts, and high-resolution S-102 bathymetric grids for narrow approaches, anchorages and large ports. Depths refer to sjøkartnull (chart datum, LAT, lowest astronomical tide) and differ from the NN2000 height reference used on land. When you compare marine and land data, you have to take that difference into account.
The programme Marine grunnkart i kystsonen (marine base maps for the coastal zone) is a joint effort between Kartverket, Norges geologiske undersøkelse (NGU) and Havforskningsinstituttet, and gathers full coverage knowledge of seabed conditions, geology and habitat types. The programme has been running since 2005, but coastal coverage is still uneven: outer fjord areas and main fairways are often well mapped, while shallow poll basins and enclosed bays have data gaps. Work in shallow coastal areas requires permission under havne- og farvannsloven (the Harbours and Fairways Act), and the authorities may ask for further documentation to clarify the consequences of the work.
The uses are wide-ranging: port planning, fisheries and aquaculture, preliminary design of subsea cables and pipelines, volume calculations for infill, emergency planning, and the delimitation of protected areas. For developers, sea depth is often decisive for where a quay can be founded, or how much fill is needed to raise an artificial islet.
In Placepoint you can switch on sea depth and coastal data under the Coast and fishing map layer when a property lies in the shoreline zone or in a port area.
How the dataset appears on the map
The dataset is part of the map layer Coast and fishing:
From Placepoint's glossary: Sea depth
More information: Kartverket: Til sjøs, Mareano
English: Sea depth.
Frequently asked questions
What is sea depth data and who produces it?
Sea depth data (bathymetry) maps the topography of the seabed. In Norway it is produced mainly by Kartverket and Norges geologiske undersøkelse (NGU), and it is available through the national map portals.
Who uses sea depth data?
Sea depth data is used by port planners, fisheries and aquaculture operators, the defence sector, the petroleum industry and developers of coastal infrastructure such as jetties, quays and subsea cables.
What is bathymetry?
Bathymetry is the science of measuring and mapping water depths. Bathymetric maps show depth contours below the sea surface, in the same way as height contours on topographic maps.
Why does sea depth data matter for coastal development?
Sea depth determines the options for a quay, the foundations for marine structures and the volume of fill needed. It is critical information for all development in port and coastal zones.
Can I find sea depth data in Placepoint?
Yes, Placepoint includes depth data as a map layer for coastal and port areas, so developers can quickly assess the options and constraints for properties near the sea.