This open access volume contains selected papers of the 2021 Scientific Assembly of the
International Association of Geodesy - IAG2021. The Assembly was hosted by the Chinese Society
for Geodesy Photogrammetry and Cartography (CSGPC) in Beijing China from June 28 to July 2
2021. It was a hybrid conference with in-person and online attendants. In total the Assembly
was attended by 146 in-person participants and 1 123 online participants. The theme of the
Assembly was Geodesy for a Sustainable Earth. 613 contributions (255 oral presentations and 358
poster presentations) covered all topics of the broad spectrum considered by the IAG: geodetic
reference frames Earth gravity field modelling Earth rotation and geodynamics positioning
and applications the Global Geodetic Observing System (GGOS) geodesy for climate research
marine geodesy and novel sensors and quantum technology for geodesy. All published papers were
peer-reviewed and we warmly recognize the contributions and support of the Associate Editors
and Reviewers.
