A hydrographic office is an organization which is devoted to acquiring and publishing hydrographic information. Historically, the main tasks of hydrographic offices were the conduction of hydrographic surveys and the publication of nautical charts. In many countries, various navigation-related services are now concentrated in large governmental organizations, sometimes termed "maritime administration" (however, the International Hydrographic Organization uses the term "hydrographic offices" for its member organizations). Besides nautical charts, many hydrographic offices publish a body of books and periodicals that are collectively known as nautical publications. The most important of these are: Sailing Directions (or pilots): detailed descriptions of areas of the sea, shipping routes, harbours, aids to navigation, regulations etc. lists of lights: descriptions of lighthouses and lightbouys tide tables and tidal stream atlases ephemerides and nautical almanacs for celestial navigation Notice to Mariners: periodical (often weekly) updates and corrections for nautical charts and publications Hydrographic organizations may also be involved in services such as: pilotage search and rescue maintenance of lighthouses and other aids to navigation ice breaking weather observation and information sea traffic information and surveillance maritime research regulatory affairs of ship safety History In the development of hydrographic services, shipping organizations played a part, but the major players were the naval powers. Recognizing hydrographic information was a military advantage these naval organizations, usually under the direction of a "Hydrographer," utilized the expertise of naval officers in collecting hydrographic data that was incorporated into the navy's collection. In order to distribute the processed information (charts, directions, notices, and such) these organizations often developed specialized printing capabilities. Hydrographic organisations of some countries Australia Hydrographic tasks in Australian waters were performed by the United Kingdom's Royal Navy since the 19th century. In 1920 the Australian Hydrographic Service was formed as a part of the Royal Australian Navy. Brazil Hydrographic tasks in Brazilian waters were performed by the (DHN) since 02/02/1876. Canada Starting in 1883, the "Georgian Bay Survey" was responsible for hydrographic surveying of Georgian Bay and Lake Huron. Its geographic area of responsibility increased and in 1904 the name was changed to the "Hydrographic Survey of Canada." The current name Canadian Hydrographic Service (CHS) was adopted in 1928. In 1951, Canada became a State Member of the International Hydrographic Organization (IHO) and the Dominion Hydrographer is Canada's representative. Today, the mandate of CHS is found in the Canada Oceans Act, the Canada Shipping Act (Charts and Publications Regulations) and