These proceedings represent the worldwide picture of the state of the art of geodesy. The volume comprehensively covers the most recent results and supplies a good review of the new ideas developing in the field, opening a window to the future of geodesy.

This book series is composed of peer-reviewed proceedings of selected symposia organized by the International Association of Geodesy. It deals primarily with topics related to Geodesy Earth Sciences : terrestrial reference frame, Earth gravity field, Geodynamics and Earth rotation, Positioning and engineering applications.

These proceedings include the written version of 130 papers presented at the International Association of Geodesy IAG2009 "Geodesy for Planet Earth" Scientific Assembly. It was held 31 August to 4 September 2009 in Buenos Aires, Argentina. The theme "Geodesy for Planet Earth" was selected to follow the International Year of Planet Earth 2007-2009 goals of utilizing the knowledge of the world’s geoscientists to improve society for current and future generations. The International Year started in January 2007 and ran thru 2009 which coincided with the IAG2009 Scientific Assembly, one of the largest and most significant meetings of the Geodesy community held every 4 years. The IAG2009 Scientific Assembly was organized into eight Sessions. Four of the Sessions of IAG2009 were based on the IAG Structure (i.e. one per Commission) and covered Reference Frames, Gravity Field, Earth Rotation and Geodynamics, and Positioning and Applications. Since IAG2009 was taking place in the great Argentine city of Buenos Aires, a Session was devoted to the Geodesy of Latin America. A Session dedicated to the IAG’s Global Geodetic Observing System (GGOS), the primary observing system focused on the multidisciplinary research being done in Geodesy that contributes to important societal issues such as monitoring global climate change and the environment. A Session on the IAG Services was also part of the Assembly detailing the important role they play in providing geodetic data, products, and analysis to the scientific community. A final Session devoted to the organizations ION, FIG, and ISPRS and their significant work in navigation and earth observation that complements the IAG.

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.

These proceedings contain 23 papers, which are the peer-reviewed versions of presentations made at the Joint Scientific Assembly of the International Association of Geodesy (IAG) and the International Association of Seismology and Physics of the Earth’s Interior (IASPEI). The assembly was held from 30 July to 4 August 2017 in Kobe, Japan. The scientific assembly included seven symposia organized by IAG, and nine joint symposia, along with additional symposia organized by IASPEI. The IAG symposia were structured according to the four IAG Commissions and the three GGOS Focus Areas, and included reference frames, static and time-variable gravity field, Earth rotation and geodynamics, multi-signal positioning, geodetic remote sensing, and GGOS. The joint symposia included monitoring of the cryosphere, studies of earthquakes, earthquake source processes, and other types of fault slip, geohazard warning systems, deformation of the lithosphere, and seafloor geodesy. Together, the IAG and joint symposia spanned a broad range of work in geodesy and its applications.

This open access book contains 30 peer-reviewed papers based on presentations at the 27th General Assembly of the International Union of Geodesy and Geophysics (IUGG). The meeting was held from July 8 to 18, 2019 in Montreal, Canada, with the theme being the celebration of the centennial of the establishment of the IUGG. The centennial was also a good opportunity to look forward to the next century, as reflected in the title of this volume. The papers in this volume represent a cross-section of present activity in geodesy, and highlight the future directions in the field as we begin the second century of the IUGG. During the meeting, the International Association of Geodesy (IAG) organized one Union Symposium, 6 IAG Symposia, 7 Joint Symposia with other associations, and 20 business meetings. In addition, IAG co-sponsored 8 Union Symposia and 15 Joint Symposia. In total, 3952 participants registered, 437 of them with IAG priority. In total, there were 234 symposia and 18 Workshops with 4580 presentations, of which 469 were in IAG-associated symposia.

This volume gathers the proceedings of the IX Hotine-Marussi Symposium on Mathematical Geodesy, which was held from 18 to 22 June 2018 at the Faculty of Civil and Industrial Engineering, Sapienza University of Rome, Italy. Since 2006, the Hotine-Marussi Symposia series has been produced under the auspices of the Inter-Commission Committee on Theory (ICCT) within the International Association of Geodesy (IAG). The ICCT has organized the last four Hotine-Marussi Symposia, held in Wuhan (2006) and Rome (2009, 2013 and 2018). The overall goal of the ICCT and Hotine-Marussi Symposia has always been to advance geodetic theory, as reflected in the 25 peer-reviewed research articles presented here. The IX Hotine-Marussi Symposium was divided into 10 topical sessions covering all aspects of geodetic theory including reference frames, gravity field modelling, adjustment theory, atmosphere, time series analysis and advanced numerical methods. In total 118 participants attended the Symposium and delivered 82 oral and 37 poster presentations. During a special session at the Accademia Nazionale deiLincei, the oldest scientific academy in the world, six invited speakers discussed interactions of geodesy with oceanography, glaciology, atmospheric research, mathematics, Earth science and seismology.

These proceedings contain a selection of peer-reviewed papers presented at the International Symposium on Geodesy for Earthquake and Natural Hazards (GENAH), Matsushima, Japan, 22-26 July, 2014. The scientific sessions focused on monitoring temporal and spatial changes in Earth's lithosphere and atmosphere using geodetic satellite systems, high rate GNSS as well as high resolution imaging (InSAR, Lidar). Researchers in various fields of geodesy discussed the role of geodesy in disaster mitigation and how groups with different techniques can collaborate toward such a goal.

The fourth edition of this textbook has been thoroughly revised in order to reflect the central role which geodesy has achieved in the past ten years. The Global Geodetic Observing System established by the IAG utilizes a variety of techniques to determine the geometric shape of the earth and its kinematics, the variations of earth rotation, and the earth’s gravity field. Space techniques play a fundamental role, with recent space missions also including gravity field recovery. Terrestrial techniques are important for regional and local applications, and for validating the results of the space missions. Global and regional reference systems are now well established and widely used. They also serve as a basis for geo-information systems. The analysis of the time variation of the geodetic products provides the link to other geosciences and contributes to proper modelling of geodynamic processes. The book follows the principal directions of geodesy, providing the theoretical background as well as the principles of measurement and evaluation methods. Selected examples of instruments illustrate the geodetic work. An extensive reference list supports further studies. The book is intended to serve as an introductory textbook for graduate students as well as a reference for scientists and engineers in the fields of geodesy, geophysics, surveying engineering and geomatics.