Nautical charts are the foundation for safe navigation. When navigating narrow channels, charts in the largest scale available should always be used as these give the best and most detailed information about the waters. Smaller scale charts are very simplified and are not edited to support navigation in coastal waters.
The publication date can be found in the title area. This date will provide the user with a guideline to how reliable the chart is. Please check the "Printing and Maintenance" section for further information.
Due to the rapid development of both shipping and electronic navigational aids, the demand for reliability in nautical charts is now greater than ever. The chart reliability is very much dependent on the technology available to the hydrographical service.
Charts based on older surveys do not fully meet today's reliability standards. Therefore, Norwegian Hydrographic Service frequently receive discrepancy reports. These reports are promptly handled.
If required, a notice will be published in the Etterretninger til sjøfarende (Efs). Nautical charts are updated at the next print.
Updating and Printing of Charts
The year of publication is shown in the title block. This information will help the mariner in judging the reliability of the chart. As charts are subject to frequent changes, they are reprinted regularly.
The month and year of printing as well as the latest Notices to Mariners it is updated to,is shown in the lower left-hand corner of the chart. See example below. "POD: 22. Dec 2016. Corrected to "Efs" No 23/16." means that map file is generated 22.12.2016 and the notices published in Efs no. 23/16 is corrected in the chart.
Hydrographic charts on paper are now sold only as POD-Charts (Print on demand) and must be ordered from authorized POD dealers. Charts are subject to frequent changes, and important amendments are continuously published in the Norwegian Notices to Mariners, Etterretninger for sjøfarende (Efs).
It is therefore the responsibility of the mariners to keep their charts updated in accordance with Efs after the date of printing. A Norwegian chart is updated when all corrections from the Efs concerning that chart are applied.
Overview with printing dates for Norwegian charts (pdf).
Print on Demand (POD)
The Norwegian Hydrographic Service offers a Print on Demand (POD) service. Print on Demand service is offered for all Norwegian charts and can be purchased from approved suppliers of The Norwegian Mapping Authority's maps and charts.
Traditionally, paper charts were issued every few years. As time passes, there would be messages from the Norwegian Notices to Mariners, Etterretninger for sjøfarende (Efs), that were not reflected in the chart at selling time. This meant that even though the chart was bought today, many important corrections could have been issued since the chart was printed, and mariners had to manually update the chart with the Efs updates since the chart was published. With POD this is no longer necessary, as POD-charts are automatically and continuously updated to the latest Efs.
When a POD chart is purchased, the mariner only has to review the Efs’ published after the POD production, in order to have a fully updated chart. This will typically be limited to the latest Efs.
Chart updating starts as soon as an Efs is published. All updates shall be performed before the next Efs is issued (i.e. during a 14 day period). POD charts may also include updates that have not yet been published in an Efs.
POD: "Print on Demand" is printed in red text on the left and right side of the chart frame. A text box in the lower left corner displays different dates and Efs reference.
Source diagram in charts
The source diagram printed in the chart title box shows when the survey was performed and the quality of the depth data. This provides an indication of the accuracy of the product. Areas surveyed before about 1960 did not receive full seafloor coverage and depth anomalies may be expected.
There may be undiscovered depths in older surveyed areas. Caution must therefore be taken when sailing in these areas. It is dangerous to sail outside marked areas/recommended track.