The International Association of Geodesy

2024 marks the 162nd anniversary of the founding of the International Association of Geodesy. In 1862, 15 States agreed to cooperate in a "Central European Arc Measurement" project to observe the shape of the Earth. Besides leading to an improved knowledge of the shape of the Earth, the measurements taken during this project also led to an improved reference frame and geoid for Central Europe. In the course of taking these measurements scientific issues were encountered that also had to be addressed. The spirit of cooperation in both taking operational measurements and conducting scientific research that exists today within the IAG has been a hallmark of the IAG ever since it was founded in 1862.The dual nature of the IAG, in advancing both observations and science, is reflected in the organizational structure of the IAG. Services are responsible for advancing geodetic observations in their area of expertise; Commissions and Inter-commission Committees are responsible for advancing geodetic science; Projects are incubators for new initiatives; the Communications and Outreach Branch, together with GGOS, is responsible for promoting geodesy to the other sciences and to society at large; and GGOS, the Global Geodetic Observing System, is meant to integrate the diverse geodetic observations into a coherent geodetic imaging system of the Earth as a whole.One of the strengths of geodesy is its interdisciplinary nature. Geodetic observations contribute to improving our understanding of many different Earth processes, from space weather to core dynamics. This affords the opportunity for geodesists to collaborate with scientists from many different disciplines. Besides the value to science, geodetic data and products are also of great value to society. The International Terrestrial Reference Frame (ITRF) provided by the International Earth Rotation and Reference Systems Service (IERS), one of the 12 Services of the IAG, underpins location-based services like navigation aids on cell phones. By forging collaborations with other organizations, the IAG can ensure that its data and products continue to meet the needs of both its scientific and societal customers.