World Hydrography Day: History, Theme, and Significance

OV Digital Desk

21 June is observed as World Hydrography Day. It is celebrated every year to publicise the work and efforts of hydrographers and the importance of hydrography.

World Hydrography Day 2023: Theme

The theme for World Hydrography Day 2023 is “Hydrography – underpinning the digital twin of the ocean.”

The previous year’s themes of World Hydrography Day are mentioned below:

Year Theme
2022 Hydrography – contributing to the United Nations Ocean Decade
2021 100 years of international cooperation in hydrography
2020 Hydrography enabling autonomous technologies
2019 Hydrographic information Driving marine knowledge
2018 Bathymetry – the foundation for sustainable seas, oceans, and waterways
2017 Mapping our seas, oceans, and waterways – is more important than ever


Quick facts about hydrography

Hydrography is the science that measures and describes the physical features of the navigable portion of the Earth’s surface and adjoining coastal areas.  Here are quick facts about sea.

  • Hydrographers measure water depth and search for shoals, rocks, & wrecks that could be hazards to navigation.
  • The average ocean depth is 3.7 kilometers (2.3 miles).
  • As far as we know, the ocean is 36,200 feet (11,000 m or almost 7 miles) deep at its deepest point. On average, the ocean is about 12,100 feet (3,688 m) deep.
  • Animals living in the bathypelagic zone or deeper never see sunlight. Some organisms living there, such as vampire squid and humpback anglerfish, produce their own light. More than 99 percent of Earth’s inhabitable space is in the open ocean.
  • The ocean produces more than 50 percent of the air we breathe.
  • Humans have only explored 5 percent of the world’s oceans. However, it is believed that humans have impacted every part of the ocean with waste and chemical pollution.

World Hydrography Day: History

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.