These data are used as basis for the NHS' digital and analogue chart products and are very detailed. It is therefore defined as classified material by the Armed Forces. 

Modern surveying is carried out using multi-beam echo sounders. Single-beam echo sounders and hand lead were used earlier, which means that the data density will vary depending on the data source and age. Most of the NHS hydrographical survey data is available in a digital format (sosi, shape or xyz files), but there are still some fair sheets available only in paper format. The analogue products are generally scaled 1:20,000, but a larger scale is often used for harbours and some narrow channels. Modern soundings are not scale-dependant. 

Digital deliveries of modern hydrographical survey data often consist of soundings only. Depth contours can be generated if agreed, or the unclassified depth contours can be used. The analogue fair sheets and older single beam survey data will usually cover several topics: coastline, foreshore, navaids, bottom conditions, etc.

 See coverage

Administrative Procedures
Interested parties can send a request to the Norwegian Hydrographic Service for release of hydrographical survey data. The name of the area (fjord or location) and the grounds for the application must be included. A copy of the maritime chart with a highlighted area showing the area for which more details are wanted should preferably be included. The client will soon receive an answer with information stating when the area in question was surveyed, scale and size of the area, etc.

The Norwegian Hydrographic Service will forward the application to the Norwegian Navy, which will process the request. The application will normally be approved on the condition that the data is returned/destroyed within a year. The Navy may also reduce the size of the area for which data is released. 

Customer groups
Hydrographic survey data is often used for planning purposes, e.g. in connection with installation of pipelines/sea cables and developments in the ocean. When the Directorate of Fisheries receives applications from fish farmers for a licence, it will require that detailed depth data is obtained for the area.

Pricelist marine geodata