World Hydrography Day, 21 June, was adopted by the International Hydrographic Organization as an annual celebration to publicise the work of hydrographers and the importance of hydrography.
The International Hydrographic Bureau was established in 1921 for the purpose of providing a mechanism for consultation between governments on such matters as technical standards, safe navigation and the protection of the marine environment. In 1970 the name was changed to the International Hydrographic Organization (IHO). The IHO is actively engaged in developing standards and interoperability, particularly in relation to the challenges brought about by digital technologies.
In 2005 the IHO adopted the concept of a World Hydrography Day, which was "welcomed" by the United Nations General Assembly in Resolution A/RES/60/30 Oceans and the law of the sea.
The date chosen for World Hydrography Day is the anniversary of the founding of the International Hydrographic Organization.
World Hydrography Day was adopted, in the words of the UN,with the aim of:
... giving suitable publicity to its [IHO's] work at all levels and of increasing the coverage of hydrographic information on a global basis ...
Translation of this aim through World Hydrography Day is achieved by the nomination of a theme for each year's celebration. Once a theme is agreed, the IHO Member States, international and national hydrographic organisations and services develop activity programs and events that highlight the annual theme.