News

Staff Highlights: Prof. Quoqiang Shi

Urbanization brings rapid development but also exacerbates geological and environmental risk, such as land subsidence, infrastructure instability, and landslides. These challenges threaten the safety of millions and demand advanced monitoring solutions. Prof. Guoqiang Shi and his team work on urban remote sensing, leveraging Interferometric Synthetic Aperture Radar (InSAR) to monitor and analyse urban geological vulnerabilities from underground, ground surface, to the built upper ground. By integrating InSAR remote sensing, big data analytics and artificial intelligence (AI), the team aims to provide critical insights for urban resilience, infrastructure maintenance, and sustainable development.   Topic 1: Uneven Settlement in Coastal Reclamations Reclaimed areas, common in land-scarce cities like Hong Kong, are prone to uneven settlement due to soft subsurface layers. Constrained by its steep terrain, Hong Kong has over 25% of its developable land reclaimed from the sea. Using spaceborne InSAR, we detected rapid subsidence at Hong Kong International Airport’s Third Runway, a major reclaimed project. Our high-resolution data revealed soil compression patterns and fill-layer dynamics, offering engineers and policymakers actionable insights for soil reinforcement, infrastructure planning, and future reclamation projects (e.g., the ‘Lantau Tomorrow Vision’). This work underscores the need for continuous monitoring in reclaimed zones to prevent long-term risks.   Topic 2: Groundwater and Urban Land Subsidence Unlike the artificial foundations in Hong Kong, the Yangtze River Delta (YRD) has vast and flat areas of natural sediments. Excessive groundwater extraction has caused severe subsidence in cities like Suzhou, where some areas sank over 2 meters before extraction was banned in 1997. Using InSAR, we quantified the slowdown in subsidence post-ban, demonstrating the policy’s effectiveness. However, traditional geological and surveying methods failed to evaluate the groundwater policy on a city-wide scale. Figure 2 illustrates the post-ban recovery (slowing) of Suzhou’s land subsidence, as captured by satellite InSAR. These findings are vital for groundwater management in vulnerable regions (e.g., the North China Plain), supporting sustainable urban planning and resource policies.   Topic 3: Infrastructure Health and Slope Safety Beyond subsurface risks, InSAR enables large-scale structural and slope safety monitoring. In Hong Kong, we applied it to assess highway stability and generate 3D building point clouds, identifying high-risk structures. Risky slopes/landslides adjacent to buildings/transportations can be surveillance timely and located for accurate mitigation and evacuation planning. As satellite data improves, InSAR is becoming indispensable for smart city platforms, offering precise, real-time diagnostics for next-generation urban resilience solutions.   Photo 2: Reclamation subsidence and soil consolidation of the HKIA 3rd RunwayPhoto 3 & 4: Urban land subsidence recovery in Suzhou City following the implementation of groundwater extractionPhoto 5: InSAR 4D data for infrastructure and slope safety assessment   Welcome to join Prof. Shi’s team! Prof. Shi and his team are advancing InSAR algorithms for complex urban terrains and developing AI-driven models to mine geohazard data. They welcome students from diverse academic backgrounds to join LSGI and join our group. For contact details, please refer to the information below. They are looking forward to collaborating with you!   Personal web: https://guoqiangshi.github.io/ LSGI web: https://www.polyu.edu.hk/lsgi/people/academic-staff/ Email: guoqiang.shi@polyu.edu.hk   References: Jiang Z, Shi G, Wu S, et al. Unveiling multimodal consolidation process of the newly reclaimed HKIA 3rd runway from satellite SAR interferometry, ICA analytics and Terzaghi consolidation theory. Remote Sensing of Environment, 2025, 318: 114561. https://doi.org/10.1016/j.rse.2024.114561 Shi G, Huang B, Leung A K, et al. Millimeter slope ratcheting from multitemporal SAR interferometry with a correction of coastal tropospheric delay: a case study in Hong Kong. Remote Sensing of Environment, 2022, 280: 113148. https://doi.org/10.1016/j.rse.2022.113148 Shi G, Ma P, Hu X, et al. Surface response and subsurface features during the restriction of groundwater exploitation in Suzhou (China) inferred from decadal SAR interferometry. Remote Sensing of Environment, 2021, 256: 112327. https://doi.org/10.1016/j.rse.2021.112327 Shi G, Lin H, Bürgmann R, et al. Early soil consolidation from magnetic extensometers and full resolution SAR interferometry over highly decorrelated reclaimed lands. Remote Sensing of Environment, 2019, 231: 111231. https://doi.org/10.1016/j.rse.2019.111231 Shi G, Lin H, Ma P. A hybrid method for stability monitoring in low-coherence urban regions using persistent and distributed scatterers. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 2018, 11(10): 3811-3821. https://doi.org/10.1109/JSTARS.2018.2867832      

Prof. Yang Xu Honored with Outstanding Alumni Award from University of Tennessee, Knoxville

Prof. Yang Xu, Associate Head of Partnership and Associate Professor, has been awarded the prestigious Outstanding Alumni Award by the Department of Geography and Sustainability at the University of Tennessee, Knoxville. This accolade celebrates Prof. Xu's remarkable mid-career achievements and his significant contributions to the field of Geographic Information Science. University of Tennessee, Knoxville (UTK) is a public land-grant research university in the United States. The university is also classified among "R1: Doctoral Universities – Very high research activity" according to the Carnegie Classification of Institutions of Higher Education. This classification highlights the university's emphasis on research excellence and its role in promoting the academic and professional growth of its alumni. Congratulations to Prof. Xu!

LSGI Alumni Appointed as Tenure-Track Assistant Professor at Nanjing University

Dr. Jiaqi Tian, a former Ph.D. graduate from the Department of Land Surveying and Geo-Informatics (LSGI) at the Hong Kong Polytechnic University (PolyU), has been appointed as a tenure-track assistant professor at the International Institute of Earth System Science (ESSI) at Nanjing University. Under the mentorship of Professor Xiaolin Zhu and through his work at the PRIDE (PolyU Remote Sensing Intelligence for Dynamic Earth) Lab, Dr. Tian earned his Ph.D. in 2021 and developed his expertise and research capabilities in his field. ESSI is a leading academic institution in the fields of quantitative remote sensing and terrestrial carbon cycle research. LSGI is honoured by his career milestone.   Congratulations to Dr. Tian on this well-deserved achievement!   Dr Jiaqi Tian’s Personal Web Page: https://scholar.google.com/citations?user=RNCJZEYAAAAJ&hl=en PRIDE Lab: https://xzhu-lab.github.io/

PolyU Achieves Prestigious Global Rankings in Geography and Remote Sensing

The Hong Kong Polytechnic University (PolyU) has achieved impressive global rankings, highlighting its academic excellence. PolyU's Geography programme is ranked 37th in the QS World University Rankings by Subject 2025, and its overall QS ranking has risen to 57th in 2025. The Remote Sensing discipline has also advanced significantly, moving from 38th in 2023 to 15th in the ShanghaiRanking's Global Ranking of Academic Subjects 2024. These accomplishments reflect the Department of Land Surveying and Geo-Informatics (LSGI)’s commitment to excellence in academics, research, and industry partnerships, showcasing our dedication to advancing knowledge in Geography and Remote Sensing. PolyU's achievements affirm its status as a leading institution in the Asia-Pacific region and beyond. By fostering innovation and collaboration, the university attracts top talent and forms strategic partnerships, enhancing its academic and research strengths. LSGI is proud of its contributions to these successes. For more details, you can visit the QS University Subject Rankings for Geography and the ShanghaiRanking's Global Ranking of Academic Subjects 2024 for Remote Sensing.

Feature Talk "Seeing and Unseen Underground Utilities in 3D" at Geospatial Lab

On 22 February 2025, Ir. Prof. Wallace Lai, Associate Head of Department (Teaching) was invited to be the guest speaker for a feature talk "Seeing and Unseen Underground Utilities in 3D" at the Geospatial Lab. The talk attracted 23 participants who attended in person and 30 people participated online. We sincerely thank all participants for their enthusiastic engagement and the support from Geospatial Lab. This presentation explored the intricacies of Hong Kong's underground pipelines, highlighting methods to accurately locate them without excavation. During the interactive session, participants also discovered detection technologies, gaining valuable insights into the measurement and data analysis of the underground world. Click here to read more.

LSGI Joint Research with International Scientists Unveils Ice Sheet Melt Behavior in Greenland Using Satellite Positioning Data

We are thrilled to share that Prof. Jianli CHEN, Professor of the Department of Land Surveying and Geo-informatics (LSGI) together with a team of global researchers, have integrated various modern space geodetic techniques, particularly satellite positioning data, to monitor the subsidence of vertical bedrock and successfully quantify summer water storage in the Greenland ice sheet. This groundbreaking research, published in the prestigious journal Nature, offers new insights and evidence regarding the contribution of ice sheets to global sea-level rise. The Greenland ice sheet, second only to Antarctica in size, plays a crucial role in global sea-level rise. If it were to melt completely, sea levels could rise by an alarming seven meters. Despite its significance, many aspects of how water accumulates, is stored, and is released within the ice sheet remain unclear. Prof. Jianli Chen, collaborated with experts from Hong Kong, Mainland China, the US, the Netherlands, and Belgium, has made significant strides in understanding these processes by integrating advanced satellite positioning data and other space geodetic techniques. The research team focuses on the evolution meltwater storage to gain a deeper understanding of ice sheet melting behavior and its effects on sea-level rise. They have been at the forefront of utilizing the Greenland GPS Network (GNET) and satellite gravity data from NASA’s Gravity Recovery and Climate Experiment. With nearly 22 Global Navigation Satellite System (GNSS) stations positioned around Greenland, they continuously gather positioning data. This has led them to conclude that high summer temperatures could become a regular occurrence in the future. Accurately predicting meltwater storage during these periods is essential for evaluating sea-level rise. Prof. Chen highlighted that the study, which took years of preparation, not only integrated various modern space geodetic techniques but also involved challenging expeditions to some of the most remote areas on Earth. He emphasized that the significant results highlight the importance of extensive international cooperation in addressing climate change challenges. Their research would contribute to achieving accurate model performance for warmer years, which would aid in projecting ice-sheet behavior and its impact on sea-level rise in the coming decades. This research underscores our academic staff's dedication to advancing scientific knowledge and addressing the pressing issue of climate change. Our work is vital for developing accurate models to predict future sea-level changes, particularly in light of anticipated Arctic warming.    Media coverages: 18 Feb 2025 Oriental Daily News (格陵蘭融冰機制 理大以衞星數據解謎) - https://polyu.me/4b2Bzv2 Ming Pao Daily News (理大衛星數據測格陵蘭融水) – https://polyu.me/431denw am730 (理大參與研究格陵蘭冰蓋融化 助預測海平面上升速度) - https://polyu.me/3X3Goyi Ta Kung Pao (理大參與研究格陵蘭冰蓋融化 助預測海平面上升速度) - https://polyu.me/3X17FBB Wen Wei Po (理大與國際專家靠衛星定位數據 揭示格陵蘭冰蓋融化機制)- https://polyu.me/4hGscU6 Hong Kong Commercial Daily (理大與國際專家合作運用衛星定位數據 助預測海平面上升速度) - https://polyu.me/415fWpm Dot Dot News (理大參與研究格陵蘭冰蓋融化 助預測海平面上升速度) - https://polyu.me/4hFRBgV Line Today (理大參與研究格陵蘭冰蓋融化 助預測海平面上升速度) - https://polyu.me/42Zm1WH Hong Kong China News Agency (理大參與研究格陵蘭冰蓋融化 助預測海平面上升速度) - https://polyu.me/4bbDSMj 19 Feb 2025 Wuxi Daily (理大與國際專家合作運用衛星定位數據 揭示格陵蘭冰蓋融化機制) - https://polyu.me/4gNsebR 羊城晚報 (創新採用衛星數據破解冰蓋融化國際難題 理大學者參與研究助預測海平面上升速度) - https://polyu.me/4k1P4iC 南方日報 (理大研究揭格陵蘭冰蓋融化機制 助預測海平面上升速度) - https://polyu.me/41pV6RR Sina (創新採用衛星數據破解冰蓋融化國際難題 理大學者參與研究助預測海平面上升速度) - https://polyu.me/41jxQFX Sohu (理大研究揭格陵蘭冰蓋融化機制 助預測海平面上升速度) - https://polyu.me/3X6cgT6 Zhihu (理大參與研究格陵蘭冰蓋融化 助預測海平面上升速度) - https://polyu.me/4b7ImmY  

PolyU Osaka Study Tour 2025

From 4 to 10 January 2025, a group of 24 LSGI students, led by Prof. Wallace Lai, Prof. Qing Pei, Miss Stella Tse from Department of Land Surveying and Geo-Informatics (LSGI) visited Osaka and Kyoto for a 7-day study tour supported by the university. The aim of this tour was to explore the elements of spatial data science and smart cities.    At the Osaka City Abeno Disaster Prevention Center, students engaged in practical exercises that illustrated the importance of disaster preparedness. They learned why cars should not be used during a tsunami, experienced how an Earthquake shakes the Earth in a simulator, and practiced how to 'crawl' properly amid heavy smoke. Prof. Pei-liang Xu from the Disaster Prevention Institute at Kyoto University provided valuable insights into Japan's earthquake warning system, which utilizes a sophisticated network of spatial data science and technologies, including GNSS, GIS, remote sensing, geodesy, and seismology. He emphasized the philosophical dimension of disaster research, urging students to critically question scientific claims with the challenge: "Don't trust what 'Science' or 'Nature' tells you. If you care, question it and prove it yourself." The exploration of "Disaster" extended to its man-made dimensions through discussions led by Prof. Keiji Yano, Institute of Disaster Mitigation for Urban Cultural Heritage from Ritsumeikan University, who introduced his 20 years of effort on 'Virtual Kyoto'. It aims to preserve the rich Kyoto's cultural heritage from various disasters via technologies like GIS, cartography, aerial photogrammetry, laser scanning, and AI. This initiative highlights the power of a map, which is not just a large piece of paper, but a vivid story-telling vehicle recording our past and present leading us to the future. In a world where heritage is endangered, mitigation and preservation of heritage from disaster are a serious matter of humanity and should be made known to everyone. The students were stunned at how the techs they have been learning in LSGI are so closely related to humanities and heritage conservation, traditionally perceived as separate domains.    The tour also included a visit to the Kyoto Museum for World Peace led by Prof. Keiji Yano. It is a solemn place where facets of war should be presented in a multitude of ways aimed at avoiding it. Ms. Miki Taguwa, the curator of the museum, kindly guided the students through the various peace-making exhibits.  With the assistance of Dr. Pei Qing's excellent Japanese translation, Prof. Wallace Lai was able to explain the discovery of WWII fortification and field positions in his 'Geo-project 1941' originated from the Battle of Hong Kong.    This study tour not only broadened our students' understanding of disaster mitigation but also illuminated the profound interconnectedness of science, technology, and the humanities in addressing the challenges faced by society. 

PolyU Tokyo Study Tour 2025

A group of 21 students from the Department of Land Surveying and Geo-Informatics (LSGI) at the Hong Kong Polytechnic University (PolyU), led by Prof. Wu Chen, Head of Department, Dr. Sissi Chen, Lecturer, and Ms. Serein Han, Scientific Officer from LSGI, participated in a study tour in Tokyo from 4 to 10, January 2025. The National Museum of Nature and Science gave a great look at the natural world and science. The exhibits on biodiversity and the history of life on Earth were very interesting. They reminded us of the balance that keeps our planet going. Visiting Metropolitan Area Outer Underground Discharge Channel is one of the tour's highlight, known as the "Underground Temple". This critical flood management infrastructure demonstrated the extensive efforts required to protect urban areas from natural disasters through big tunnels. Prof. Wu Chen, posed thought-provoking questions regarding the channel's maintenance and operational methods: "What is the cleaning method and period?" "Why was this channel built hermetically?", and "How often will inspections be done?" These questions deepen the understanding of such a monumental engineering project. This visit showed the critical role of innovative engineering in creating urban environments, highlighting how such advancements are essential for the sustainable development of strong cities.  The Tokyo Sewerage Museum ‘Rainbow’ gave a good look at the systems that support city life. Learning about wastewater treatment and sewerage management showed us the complex processes that are important for public health and the environment. This visit made us think more about how our daily habits affect these systems and the environment. At the Miraikan, we was inspired by how technology can shape our future. The exhibits on robotics, space exploration, aging in Japan and artificial intelligence were interesting and made us think about the ethical side of technological advancements. This visit made us think about how we can use innovation to solve global problems and make sure everyone benefits. The Narusawa Mt. Fuji Museum gave a different view, focusing on the natural beauty and geological importance of Mt. Fuji. The exhibits on volcanic activity and the cultural importance of Mt. Fuji made us appreciate this landmark more.  The tour provided a profound exploration of the intersections of nature, technology, and culture. Participants expressed their gratitude for the opportunity to engage with these remarkable sites and enthusiasm for applying their newly acquired insights to foster personal growth and a broader understanding of the world. 

Delegation from Southwest Jiaotong University Visits LSGI

On 8 January 2025, a delegation from Southwest Jiaotong University visited The Hong Kong Polytechnic University (PolyU) for a half-day exchange at the Department of Land Surveying and Geo-Informatics (LSGI). The delegation was warmly welcomed by Prof. Wu, Associate Head of Research at LSGI, along with all the programme leaders from the department. The visit commenced with a meeting where both institutions shared their latest managerial experiences and explored potential areas for collaboration. Following the meeting, the delegation was given a tour of two of LSGI's laboratories: the “Laboratory for Smart City and Spatial Big Data Analytics” and the “Underground Utility Survey Laboratory,” where visitors were introduced to advanced techniques and tools used for subsurface mapping and utility management. The laboratory in charge, Prof. John Shi, demonstrated how big data and geospatial technologies are being leveraged to enhance urban living and sustainability, with cutting-edge equipment and methodologies highlighting PolyU's commitment to addressing urban infrastructure challenges. This visit marks a significant step in strengthening the partnership between Southwest Jiaotong University and PolyU, paving the way for further collaboration in the field of land surveying and geo-informatics.

Prof. Jianli Chen Elected as AGU Fellow

Prof. Jianli Chen, a full professor in the Department of Land Surveying and Geo-Informatics at The Hong Kong Polytechnic University, has been elected as an AGU Fellow. Prior to joining PolyU under the Strategic Hiring Scheme in 2022, Prof. Chen dedicated 28 years of his academic career to the Center for Space Research at the University of Texas at Austin. He is a globally recognized expert in space geodesy and its applications in Earth sciences. In 2005, he received the Presidential Early Career Awards for Scientists and Engineers (PECASE), the highest honor in the United States for early career scientists and engineers, making him the first recipient in the field of geodesy. Prof. Chen joins a prestigious group of 54 individuals in the 2024 Class of AGU Fellows. The American Geophysical Union (AGU), the world's largest Earth and space science association, annually bestows this honor on a select number of individuals who have made exceptional contributions to their fields. Since its inception in 1962, less than 0.1% of AGU members have been selected as Fellows each year. AGU Fellows are recognized for their scientific eminence, demonstrated through breakthroughs, discoveries, or innovations that advance Earth and space sciences. They also serve as external experts, advising government agencies and other organizations upon request. Prof. Chen was selected for his exemplary leadership and outstanding scientific achievements, which have significantly advanced our understanding of space geodesy and global climate change. Prof. Chen has been extensively involved in data processing, results validation, and geophysical interpretation of the Gravity Recovery and Climate Experiment (GRACE) satellite gravity mission. He is a leading science team member of both the GRACE and GRACE Follow-On missions. His pioneering contributions to the study of global sea level rise, glacial melting, terrestrial water storage change, and groundwater depletion using GRACE/GRACE-FO satellite gravity measurements and other geodetic observations have been widely recognized. His research has been covered by numerous media outlets worldwide, including USA Today, BBC News, The Washington Post, Discovery News, National Geographic, ABC (Australia), New Scientist, China Daily, People’s Daily, and CCTV. "I am deeply honored and humbled to be elected as an AGU Fellow. This recognition is not only for myself but also for the people who have worked with and supported me over the years. It motivates me to continue striving for excellence in my research," said Prof. Jianli Chen. Honorees was recognized at AGU24, which convened more than 25,000 attendees from over 100 countries in Washington, D.C., and online from December 9-13, 2024. Reflecting the theme 'What's Next for Science,' the Honors Reception celebrated groundbreaking achievements that illustrate the continual advancement of science, inspiring the AGU community with their stories and successes. Prof. Chen was also invited and attended AGU 2024 Honors Ceremony as AGU Union Member 2024, for outstanding achievements and sea level and climate research, terrestrial Waters and Earth-rotation using space geodesy techniques. Watch the 2024 honors ceremony recording here: https://www.agu.org/honors/ceremony (35:24 - 35:46)