From OpenStreetMap Wiki
Jump to navigation Jump to search
The free Nautical Chart
Author: Team of OpenSeaMap
Slippy map:

water depths by crowd sourcing:

OpenSeaMap is a worldwide open source project for visualisation of a free nautical database using OpenStreetMap data.

History and fundamentals

OpenSeaMap was created in 2009 in response to a great need for freely-accessible seafaring maps. OpenSeaMap's goal is to add nautical and tourism information that would interest sailors into OSM and to present this in a pleasing and usable way. This includes beacons, buoys and other seamarks, port information, repair shops, ship supplies and much more, but also shops, restaurants and places of interest. OpenSeaMap is part of OpenStreetMap and uses its database.

We started with areas "Warnemünde" and Kieler Förde.

OpenSeaMap is an free nautical chart, and also a touristical land map. The basemap is rendered with Mapnik using the OpenStreetMap-data. This map is extended with nautical data that is saved in the OSM-Database as well. OpenLayers is used to overlay additional nautical Information, which can be displayed in a popup by clicking on the map.


OpenSeaMap can be viewed online.

We have implemented a Port-Pilot-Book, Wikipedia, weather reports, AIS, aerial photos, gauges, etc.

You can download the current map onto your chart plotter, laptop, tablet, smartphone, GPS-handheld for your cruise.

We collect shallow water depths. Aim is to display the profile of the coastal sea bed.

Data model

The data scheme(en) applies to the international norm IHO-S-57 and a new standard S-101 for Electronic Navigational Charts (ENCs), as published by the IHO. This allows a simple exchange of data with other ECDIS-Applications. Because of the complexity of attributing seamarks, there will be (unlike the usual OSM procedure) a strict separation between database as backend and the frontend, to allow users to input data without knowing S-57 and S-101. A graphical user interface will be provided in the form of a special editor.

All data which is in INT-1 can be used in OpenSeaMap. See seamark objects(en), schema(en).


See also Project page "SeaMap-Editor"

We use three comfortable multilingual Editors:

It is also possible to edit using iD. Most tagging information can be found through the Seamarks page of the wiki.

Mailing list and forum

  • openseamap-forum (en)/(de) Everything about using and creating maps for OpenSeaMap:
  • openseamap-develop (en) OpenSeaMap developer discusssion:
    Sign up - Archives



Are you a seaman, sailor, motorboat driver, kayaker? You can contribute a great deal using your GPS-device: When you are on a cruise, or live near a port, please walk along the border of each mole/pier. Then upload the track if you have time and create a port map. Of course you are free to add any information you find interesting, which will then be available to seaman world-wide. You can also begin at home and trace orthophotos of your destination, which you can refine on-site. Every bit of help is valuable for the project: Are the areas you know correct, do you find errors you could repair? Do you even work on a ship and know many ports world-wide?

Orthophoto painter

Do you like to trace aerial photographs? In many parts of the world there are high-resolution aerial photographs from Bing available. You can use them to create exact port plans and to refine the coast line. This way, you can dream about making a nice cruise, even when you are still at home...

OSM member

OSM members, including those that are not (yet?) seafarers, are welcome to the project! Anyone can map a port. A port is a rather exciting mapping-project, ..... . A well-illustrated manual helps you with that. The template "Hafen" in JOSM helps you filling in the Tags, and several wiki pages explain the specifics of a SeaMap in several languages.

A bit more complicated is adding seamarks, which requires you to have some nautical knowledge. However, maybe you have a friend or colleague that can support you in that regard? You with your OSM Knowledge and he/she with nautical experience. Skills obtained in a theory training "Yachtmaster qualification" are sufficient.


Are you a programmer? There is much work to do - the de:Seamap-Editor, the renderer which draws the maps, the website, the internationalisation, the database, and many supporting programs. Currently, we also have two places for students about to write their diploma thesis. (?)

We are happy to tell you more: Olaf

Visit us on GitHub:


Do you speak English, French, ....? We would like to provide the SeaMap in as many languages as possible. To this end, we want to translate the website and the wiki manuals as soon as possible to English. Others can then translate into their national language. We are happy to tell you more: Markus

Graphic artist

Are you a graphic artist? A picture tells more than thousand words. You could illustrate our wiki pages, create Icons for the map, optimize graphics or layout, organize pictures. We are happy to tell you more: Markus

Data contributor

Are you a port captain, marina owner, shipowner, charter operator? Maybe you have access to data that OpenSeaMap would be allowed to use? Aerial photos, maps and port plans, lists, tables, indices? We probably can use it somewhere. We are happy to tell you more: Markus


Are you an oceanographer, cartographer, bathymetrist?, meteorologist? If so, you probably have many ideas, how OpenSeaMap could be improved?! For example, we still use a solution to display Water depth, we work on a sea profile and experiment with AIS. We can use your help. We are happy to tell you more: Markus

Official nautical maps

information sign

The use of official topical nautical maps is part of a good seamanship.

OpenSeaMap serves for the preparation of a cruise and as an overview and supplement to other nautical maps.

OpenSeaMap cannot substitute for official maps.

Quality and coverage


All data in the OpenStreetMap data bank, so also those of OpenSeaMap, stand under the licence ODbL. The licence says that any kind of use of OSM data, also commercially, is allowed, nevertheless, it has to be declared, that the data come from OSM, and every product which is derived from OSM data must stand again under the ODbL-License.

The data are thereby compatible also with those of Wikipedia and the cooperation is easily possible.

Chart tiles are available under CC-BY-SA

Mobile applications

There do exist several Apps and solutions to use OpenSeaMap and OpenStreetMap on mobile Devices like e.g. SmartPhones.

Comprehensive list of applications using OpenSeaMap:

See Software/Mobile for further information about available software.

See also


OSM seamark resources

JOSM presets & styles

External sources