OpenSeaMap is part of OpenStreetMap
More than 1,000,000 people worldwide collect and store geological data in the OpenStreetMap database (license ODbL). This is how the basic chart and the seamark layer (license CC-by-SA)were rendered. Many data are donations from various sources. The ports, for example, were taken from the World Port Index, OpenStreetMap and SkipperGuide. The deep water depths were rendered from GEBCO data. Weather data were taken from the NOAA and rendered by Thomas. Lighthouses were found in the List of Lights and OpenStreetMap. The links to Wikipedia are from Wikipedia and images from Wikimedia Commons. The DE gauge data came from Wasser- und Schifffahrtsverwaltung (PEGELONLINE), the CH ones from Bundesamt für Umwelt, Abteilung Hydrologie. The aerial photographs are from Bing. AIS data were provided by Syros University and ship tracking date by INTERMAR and SatPro. Inland waterway data in DE are provided by Wasser- und Schifffahrtsverwaltung des Bundes (WSV). The height data (ASTA GDEM) is a product from METI and NASA provided by OpenMapSurfer of Uni Heidelberg. Depth data are collected by Crowdsourcing and computed, or are provided by third parties, e.g. from Bundesamt für Seeschifffahrt und Hydrographie (BSH) and the Ministry of Landwirtschaft, Umwelt und Verbraucherschutz Mecklenburg-Vorpommern (official chart).
The data are stored on Linux servers in a Postgres/PostGIS database and rendered with Mapnik or Osmarender and illustrated with OpenLayers. We use and write largely free software.
Markus and Olaf, who is also senior programmer, are the maintainers of this website. They are supported by a team of committed programmers that contribute thousands of lines of code. The website was started by Rolf and Dennis and is maintained by Markus and a team of translators. Peter is responsible for the harbour Wiki, Thomas for the weather data, Jürgen and Alexej for the offline charts, Martin for water depths and Dominik, Jens and Axel work on shallow water depths. Helge developed the iOS app, Werner contributed the cartoons and graphics and Werner and Malcolm developed the editor.
The servers are provided by the KNF and friendly organizations and serviced by Jörg, Daniel and other admins. The NMEA Logger was developed by Wilfried and produced by Eckhard.