image: The workflow of in-time land cover change mapping with multimodal data, dense surface observations, and SAM (FGP 3.0).
Credit: Journal of Remote Sensing
Land cover is constantly changing due to climate pressures and human activities, yet traditional satellite monitoring often misses rapid events. A new multimodal framework, FROM-GLC Plus 3.0, integrates near-surface cameras, satellite imagery, and AI to provide daily, high-resolution maps of global land changes. The approach improves accuracy, captures abrupt transitions such as snow cover and flooding, and delivers parcel-level insights, offering vital support for agriculture, conservation, and disaster response.
Accurate land cover mapping underpins biodiversity protection, climate adaptation, and sustainable land use. Despite advances in remote sensing, satellite-only approaches remain limited by cloud cover, revisit intervals, and the lack of ground-truth data. Dynamic products such as Dynamic World have improved timeliness but still struggle to capture sudden transitions or validate their results. The rapid expansion of near-surface camera networks provides an opportunity to enhance monitoring by adding localized, high-frequency observations. However, challenges such as perspective mismatch and limited coverage persist. Based on these challenges, new research is needed to integrate multimodal observations and AI tools for real-time land monitoring.
Researchers from Tsinghua University and collaborators published (DOI: 10.34133/remotesensing.0728) their study in the Journal of Remote Sensing on August 26, 2025. The team developed a framework that merges satellite imagery, near-surface cameras, and advanced AI segmentation models. This innovation addresses persistent barriers in land monitoring, including cloud interference and limited revisit times, offering a system capable of near real-time global land cover mapping for applications ranging from agriculture to ecosystem conservation.
The study demonstrates that FROM-GLC Plus 3.0 surpasses previous products in both accuracy and temporal density. By reconstructing dense daily NDVI time series from camera observations, the framework achieved an average accuracy of 70.52%. It captures abrupt transitions, such as snow accumulation in North America and wetland expansion in Europe, that satellite-only systems failed to detect. Additionally, the integration of the Segment Anything Model (SAM) enables parcel-level mapping with reduced noise and sharper boundaries, providing high-resolution insights into croplands, urban areas, and natural habitats. Together, these innovations make FGP 3.0 a flexible, scalable, and timely solution for tracking environmental changes worldwide.
The framework integrates three modules: annual mapping, dynamic daily monitoring, and high-resolution parcel classification. Annual mapping combines Sentinel-1 SAR, Sentinel-2 spectral data, and near-surface camera inputs using automated spatial matching algorithms to reconstruct daily NDVI time series. This enhances accuracy across diverse ecosystems, particularly in cropland–shrubland mosaics. For dynamic monitoring, the system uses migrated sample sets and reconstructed images to detect land transitions at a daily scale, capturing short-term events often invisible to satellite-only approaches. High-resolution mapping leverages SAM, implemented through the open-source samgeo tool, to segment parcels and reduce salt-and-pepper noise, producing cleaner and more cohesive classifications. Tests in China showed the framework accurately tracked crop rotations of winter wheat and maize at the parcel level. Compared to previous versions, FGP 3.0 reduces misclassification, improves boundary precision, and scales effectively from regional to global levels.
“Satellite-only products often miss the rapid shifts that shape our environment,” said Le Yu, corresponding author of the study. “By fusing multimodal data with advanced AI models, FROM-GLC Plus 3.0 delivers daily, accurate insights at both global and parcel scales. This technology provides not only better environmental understanding but also practical support for agriculture, disaster preparedness, and sustainable land management.”
The study combined Sentinel-1 radar, Sentinel-2 multispectral imagery, and dense near-surface camera data. Automated spatial matching aligned oblique camera views with satellite pixels, while regression models reconstructed daily NDVI sequences. Random Forest classifiers were applied for land cover classification using multimodal temporal features. For dynamic updates, migrated samples ensured consistency across time periods. High-resolution parcel mapping employed the SAM model within samgeo, enabling flexible segmentation of croplands, urban structures, and water bodies. Validation was conducted across eight ecologically diverse sites on multiple continents.
FROM-GLC Plus 3.0 sets the stage for next-generation land monitoring. Its ability to capture daily, fine-scale changes enables early warning for floods, droughts, deforestation, and urban expansion. Agricultural applications include tracking crop health, rotation, and water stress at the field level, while conservationists can use the system to monitor biodiversity habitats and land degradation. As near-surface camera networks expand and AI models evolve, the framework could become a cornerstone for global environmental intelligence, supporting climate resilience and sustainable land-use strategies.
###
References
DOI
Original Source URL
https://doi.org/10.34133/remotesensing.0728
Funding information
L.Y., X. Li, H.W., Q.Z., P.W., and Z.Z. were supported by the National Key R&D Program of China (2024YFF1307600). L.Y., X. Li, H.W., and Q.Z. were also supported by the Investigation Research Program between Ecological Environment and Human Health in Wuyi Mountain (20242120035), the open project of State Key Laboratory of Efficient Utilization of Arable Land in China, the Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences (No. EUAL-2025-03), the Chebaling National Nature Reserve Phenology Monitoring Network Construction and Application Project (CBLHT-2025050), the Xizang Science and Technology Plan Project (XZ202403ZY0018), and the National Key Scientific and Technological Infrastructure project “Earth System Science Numerical Simulator Facility” (EarthLab). Z.D. was supported by the National Natural Science Foundation of China (42201367) and the Fundamental Research Funds for the Central Universities under grant DUT23RC(3)064.
About Journal of Remote Sensing
The Journal of Remote Sensing, an online-only Open Access journal published in association with AIR-CAS, promotes the theory, science, and technology of remote sensing, as well as interdisciplinary research within earth and information science.
Journal
Journal of Remote Sensing
Subject of Research
Not applicable
Article Title
FROM-GLC Plus 3.0: Multimodal Land Change Mapping with SAM and Dense Surface Observations
Article Publication Date
26-Aug-2025
COI Statement
The authors declare that they have no competing interests.