Most Download

  • Published in last 1 year
  • In last 2 years
  • In last 3 years
  • All
  • Most Downloaded in Recent Month
  • Most Downloaded in Recent Year

Please wait a minute...
  • Select all
    |
  • Journal of Geo-information Science. 2025, 27(3): 537-538.
  • TANG Junqing, AN Mengqi, ZHAO Pengjun, GONG Zhaoya, GUO Zengjun, LUO Taoran, LYU Wei
    Journal of Geo-information Science. 2025, 27(3): 553-569. https://doi.org/10.12082/dqxxkx.2024.240107

    [Significance] Cities globally face increasingly frequent multi-hazard risks, driving them pursuing more sustainable and resilient urban transportation systems. This paper presents a comprehensive systematic literature review of the application of spatial-temporal data in transportation system resilience studies. It highlights the pivotal role of spatial-temporal big data in understanding and enhancing the resilience of urban transportation systems under various hazard scenarios. Spatial-temporal big data, characterized by high temporal resolution and fine spatial granularity, has been increasingly applied to the field of transportation system resilience, providing essential support for decision-makers. [Progress] This study reveals two significant findings: Firstly, quantitative analysis of transportation system resilience is one of the most widely applied uses of spatial-temporal big data. However, real-time monitoring and early warning explorations are relatively rare. Most studies remain at the modelling and numerical simulation stage, indicating a need for more empirical studies using multi-source spatial-temporal big data. Moreover, compared to English literature, Chinese transportation system resilience studies are primarily qualitative and lack empirical research, indicating divergent research emphases between domestic and international scholars. Secondly, high-quality, multi-source spatial-temporal big data could facilitate more comprehensive spatial analysis in transportation system resilience studies. Improved data quality allows for deeper exploration from a microscopic perspective, focusing on individual behaviors and aligning closely with real-world needs. The concept of resilience has evolved from its previous post-disaster focus to a comprehensive life-cycle perspective encompassing pre-, during-, and post-disaster phases, transforming the study framework for transportation system resilience. [Prospect] As spatial-temporal big data technology advances and new transportation modes emerge, more innovations and breakthroughs in transportation system resilience studies are expected. Future research should further explore and utilize the potential of spatial-temporal big data in this field, amplifying the policy ramifications of abrupt-onset occurrences. Increased emphasis should be placed on research conducted at the scale of urban agglomerations. Simultaneously, a nuanced examination from a microscopic perspective is imperative to dissect the underlying causes and mechanisms contributing to variations in resilience among distinct groups. Despite the significant progress in transportation system resilience studies, there are still challenges in data collection, processing, and analysis. As technology progresses, researchers should leverage advanced algorithms, platforms, and tools to enhance data processing capabilities and analytical precision, facilitating more complex and detailed studies on transportation system resilience. This will provide a scientific basis for planning and managing urban transportation systems, significantly contributing to the overall resilience and sustainable development of cities.

  • HUANG Yi, ZHANG Xueying, SHENG Yehua, XIA Yongqi, YE Peng
    Journal of Geo-information Science. 2025, 27(6): 1249-1262. https://doi.org/10.12082/dqxxkx.2025.250175

    [Objectives] This study addresses the critical challenges in typhoon disaster knowledge services, which are often hindered by "massive data, scarce knowledge, and limited services." The core objective is to rapidly distill actionable knowledge from vast datasets to enhance disaster management efficacy and mitigate typhoon-related impacts. Large Language Models (LLMs), renowned for their superior performance in natural language processing, are leveraged to deeply mine disaster-related information and provide robust support for advanced knowledge services. [Methods] This research establishes a typhoon disaster knowledge service framework encompassing three layers: data, knowledge, and service. [Results] For the data-to-knowledge layer, an LLM-driven (Qwen2.5-Max) automated method for constructing typhoon disaster Knowledge Graphs (KGs) is proposed. This method first introduces a multi-level typhoon disaster knowledge representation model that integrates spatiotemporal characteristics and disaster impact mechanisms. A specialized training dataset is curated, incorporating typhoon-related texts with explicit temporal and spatial attributes. By adopting a "pre-training + fine-tuning" paradigm, the framework efficiently transforms raw disaster data into structured knowledge. For the knowledge-to-service layer, an LLM-based intelligent question-answering system is developed. Utilizing the constructed typhoon disaster KG, this system employs Graph Retrieval-Augmented Generation (GraphRAG) to retrieve contextually relevant knowledge from the graph and generate user-specific disaster prevention and mitigation guidance. This approach ensures seamless conversion of structured knowledge into practical services, such as personalized evacuation plans and resource allocation strategies. [Conclusions] The study highlights the transformative potential of LLMs in typhoon disaster management and lays a foundation for integrating LLMs with geospatial technologies. This interdisciplinary synergy advances Geographic Artificial Intelligence (GeoAI) and paves the way for innovative applications in disaster service.

  • SHI Shihao, SHI Qunshan, ZHOU Yang, HU Xiaofei, QI Kai
    Journal of Geo-information Science. 2025, 27(7): 1596-1607. https://doi.org/10.12082/dqxxkx.2025.250015

    [Objectives] Small object detection is of great significance in both military and civil applications. However, due to challenges such as low resolution, high noise environments, target occlusion, and complex backgrounds, traditional detection methods often struggle to achieve the necessary accuracy and robustness. The problem of detecting small objects in complex scenes remains highly challenging. Therefore, this paper proposes a hybrid feature and multi-scale fusion algorithm for small object detection. [Methods] First, a Hybrid Conv and Transformer Block (HCTB) is designed to fully utilize local and global context information, enhancing the network's perception of small objects while optimizing computational efficiency and feature extraction capability. Second, a Multi-Dilated Shared Kernel Conv (MDSKC) module is introduced to extend the receptive field of the backbone network using dilated convolutions with varying expansion rates, thereby enabling efficient multi-scale feature extraction. Finally, the Omni-Kernel Cross Stage Model (OKCSM), constructed based on the concepts of Omni-Kernel and Cross Stage Partial, is integrated to optimize the small target feature pyramid network. This approach helps preserve small object information and significantly improves detection performance. [Results] Ablation and comparison experiments were conducted on the VisDrone2019 and TinyPerson datasets. Compared to the baseline model YOLOv8n, the proposed method improves precision, recall, mAP@50, and mAP@50:95 by 1.3%, 3.1%, 3%, and 1.9%, respectively on VisDrone2019, and by 3.6%, 1.3%, 2.1%, and 0.7%, respectively on TinyPerson. Additionally, the model size and GFLOPs are only 6.3 MB and 11.3 G, demonstrating its efficiency. Furthermore, compared with classical algorithms, such as HIC-YOLOv5, TPH- YOLOv5, and Drone-YOLO, the proposed algorithm demonstrates significant advantages and superior performance. [Conclusions] The algorithm effectively improves detection accuracy, confirming its strong performance in addressing small object detection in complex scenes.

  • ZHAO Pengjun, CHEN Xiaoyi, WANG Yiqing, HOU Yongqi, ZHENG Yu
    Journal of Geo-information Science. 2025, 27(3): 539-552. https://doi.org/10.12082/dqxxkx.2024.240313

    [Objectives] The scale, distribution, travel mode structure, and traffic flow of passenger travel demand are the results of spatial interactions within the human social economy across different locations. The complexity of the social and economic operation systems dictates that travel demand prediction must start from the urban system to address the technical challenges of current travel demand forecasting. This paper analyzes the systematic nature of urban transportation and proposes an integrated simulation technology framework that incorporates land, population, housing, and transportation. It also summarizes traffic demand simulation and prediction technology based on urban systems and develops China's first urban system travel demand forecasting technology platform. [Methods] This technology covers sub-modules such as transportation demand distribution, transportation mode share and path allocation, land use simulation, population and employment distribution, real estate price, and carbon emissions to reflect the complete urban system. It includes a series of sub-module variables, including generalized travel cost, location accessibility, real estate price, job-housing relationship coefficients, and land use mixing degrees, to reflect the interactions among subsystems and the time lag effect. Additionally, core algorithms of sub-modules are designed to achieve urban system simulation and prediction. Using Beijing as a case study, the application of this technology platform is demonstrated. A comparison between the actual and simulated values for 2020 shows that the accuracy of simulated results for travel demand, traffic congestion situation, land use, and population distribution is above 85%. [Results] Applying this platform to Beijing, the travel demand, traffic flow, congestion index, population distribution, and land use projections for 2030 were predicted. According to the forecast results, from 2020 to 2030, the total number of traffic trips in Beijing will show a generally stable and slowly declining trend, with strong centripetal characteristics spatially, and trips within each suburb will become more balanced. There will be a slight decrease in the proportion of public transportation travel, a slight reduction in residents' average travel time, and more severe congestion compared to 2020. The expansion of land for residential areas, roads and transportation facilities, green spaces and squares, and commercial services will be more obvious. Resident population will show steady fluctuations, with finger-like extensions along major transportation corridors. [Conclusion] Overall, this paper advances urban transportation theory, innovates urban transportation simulation forecasting methods, and provides new technical support for urban and rural planning and urban transportation planning.

  • QIN Qiming
    Journal of Geo-information Science. 2025, 27(10): 2283-2290. https://doi.org/10.12082/dqxxkx.2025.250426

    [Objectives] With the rapid increase in the number of Earth observation satellites in orbit worldwide, remote sensing data has been accumulating explosively, offering unprecedented opportunities for Earth system science research to dynamically monitor global change. At the same time, it also brings a series of challenges, including multi-source heterogeneity, scarcity of labeled data, insufficient task generalization, and data overload. [Methods] To address these bottlenecks, Google DeepMind has proposed AlphaEarth Foundations (AEF), which integrates multimodal data such as optical imagery, SAR, LiDAR, climate simulations, and textual sources to construct a unified 64-dimensional embedding field. This framework achieves cross-modal and spatiotemporal semantic consistency for data fusion and has been made openly available on platforms such as Google Earth Engine. [Results] The main contributions of AEF can be summarized as follows: (1) Mitigating the long-standing “data silos” problem by establishing globally consistent embedding layers; (2) Enhancing semantic similarity measurement through a von Mises-Fisher (vMF) spherical embedding mechanism, thereby supporting efficient retrieval and change detection; (3) Shifting complex preprocessing and feature engineering tasks into the pre-training stage, enabling downstream applications to become “analysis-ready” and significantly reducing application costs. The paper further highlights the application potential of AEF in three stages: (1) Initially in land cover classification and change detection; (2) Subsequently in deep coupling of embedding vectors with physical models to drive scientific discovery; (3) Ultimately evolving into a spatial intelligence infrastructure, serving as a foundational service for global geospatial intelligence. Nevertheless, AEF still faces several challenges: (1) Limited interpretability of embedding vectors, which constrains scientific attribution and causal analysis; (2) Uncertainties in domain transfer and cross-scenario adaptability, with robustness in extreme environments yet to be verified; (3) Performance advantages that require more empirical validation across regions and independent experiments. [Conclusions] Overall, AEF represents a new direction for research in remote sensing and geospatial artificial intelligence, with breakthroughs in data efficiency and cross-task generalization providing solid support for future Earth science studies. However, its further development will depend on continuous advances in interpretability, robustness, and empirical validation, as well as on transforming the 64-dimensional embedding vectors into widely usable data resources through different pathways.

  • LIAN Peige, LI Yingbing, LIU Bo, FENG Xiaoke
    Journal of Geo-information Science. 2025, 27(3): 636-652. https://doi.org/10.12082/dqxxkx.2025.240641

    [Objectives] With accelerating urbanization and a surge in vehicle numbers, urban traffic systems face immense pressure. Intelligent transportation systems, a vital component of smart cities, are widely employed to improve urban traffic conditions, with traffic speed prediction being a key research focus. However, the complex coupling relationships and dynamically varying characteristics of urban traffic network nodes pose challenges for existing traffic speed prediction methods in accurately capturing dynamic spatio-temporal correlations. Spatio-temporal graph neural networks have proven to be among the most effective models for traffic speed prediction tasks. However, most methods heavily rely on prior knowledge, limiting the flexibility of spatial feature extraction and hindering the dynamic representation of road network topology. Recent approaches, such as adaptive adjacency matrix construction, address the limitations of static graphs. However, they often overlook the synergy between dynamic features and static topology, making it difficult to fully capture the complex fluctuations in traffic flow, which in turn limits prediction accuracy and adaptability. [Methods] To address these challenges, this study formulates urban traffic speed prediction as a multivariate time-series forecasting problem and proposes a traffic speed prediction model based on a Multivariate Time-series Dynamic Graph Neural Network (MTDGNN). Leveraging real-time traffic information and predefined static graph structures, the model adaptively generates dynamic traffic graphs to capture spatial dependencies through a graph learning layer and integrates them with static road network graphs to capture spatial dependencies from multiple perspectives. Meanwhile, the alternating use of graph convolution and temporal convolution modules constructs a multi-level spatial neighborhood and temporal receptive field, fully exploring the spatial and temporal features of traffic data. [Results] The MTDGNN model was tested on real traffic data from 397 road sections in eastern Beijing, collected between April 1, 2017, and May 31, 2017. Its prediction results were compared against nine benchmark models and seven ablation models. Compared to benchmark models, MTDGNN reduced the average MAE by at least 2.24% and the average RMSE by at least 3.98%. [Conclusions] Experimental results demonstrate that the MTDGNN model achieves superior prediction accuracy in MAE, RMSE, and MAPE evaluation metrics, highlighting its robustness and effectiveness in complex traffic scenarios.

  • WU Ruoling, GUO Danhuai
    Journal of Geo-information Science. 2025, 27(5): 1041-1052. https://doi.org/10.12082/dqxxkx.2025.240694

    [Objectives] Understanding whether Large Language Models (LLMs) possess spatial cognitive abilities and how to quantify them are critical research questions in the fields of large language models and geographic information science. However, there is currently a lack of systematic evaluation methods and standards for assessing the spatial cognitive abilities of LLMs. Based on an analysis of existing LLM characteristics, this study develops a comprehensive evaluation standard for spatial cognition in large language models. Ultimately, it establishes a testing standard framework, SRT4LLM, along with standardized testing processes to evaluate and quantify spatial cognition in LLMs. [Methods] The testing standard is constructed along three dimensions: spatial object types, spatial relations, and prompt engineering strategies in spatial scenarios. It includes three types of spatial objects, three categories of spatial relations, and three prompt engineering strategies, all integrated into a standardized testing process. The effectiveness of the SRT4LLM standard and the stability of the results are verified through multiple rounds of testing on eight large language models with different parameter scales. Using this standard, the performance scores of different LLMs are evaluated under progressively improved prompt engineering strategies. [Results] The geometric complexity of input spatial objects influences the spatial cognition of LLMs. While different LLMs exhibit significant performance variations, the scores of the same model remain stable. As the geometric complexity of spatial objects and the complexity of spatial relations increase, LLMs' accuracy in judging three spatial relations decreases by only 7.2%, demonstrating the robustness of the test standard across different scenarios. Improved prompt engineering strategies can partially enhance LLM's spatial cognitive Question-Answering (Q&A) performance, with varying degrees of improvement across different models. This verifies the effectiveness of the standard in analyzing LLMs' spatial cognitive abilities. Additionally, Multiple rounds of testing on the same LLM indicate that the results are convergent, and score differences between different LLMs exhibit a stable distribution. [Conclusions] SRT4LLM effectively measures the spatial cognitive abilities of LLMs and serves as a standardized evaluation tool. It can be used to assess LLMs' spatial cognition and support the development of native geographic large models in future research.

  • HAO Yuanfei, LIU Zhe, ZHENG Xi, QIAN Yun
    Journal of Geo-information Science. 2025, 27(9): 2070-2085. https://doi.org/10.12082/dqxxkx.2025.250129

    [Objectives] Street space serves as the primary perceptual interface for pedestrians in urban environments, and the visual quality of these spaces plays a crucial role in enhancing their vitality. Traditional evaluation methods often rely on single-objective indicators, making it difficult to effectively link objective environmental features with pedestrians' subjective perceptions. [Methods] This study proposes a novel evaluation framework based on Large Language Models (LLMs), incorporating the style dimension of subjective perception and extending traditional single-indicator quantitative analysis to a comprehensive approach that integrates both quantification and stylization. This framework utilizes Baidu Street View imagery to quantitatively assess two objective indicators, namely green view index and sky view factor, through semantic segmentation techniques. Additionally, it evaluates six subjective indicators, including vegetation diversity, building typology, building continuity, sidewalk usage, roadway usage, and signage usage, by leveraging prompt-optimized LLMs. The study then categorizes street space visual quality features within the research area using the Latent Dirichlet Allocation (LDA) topic model, aiming to explore the spatial characteristics of different streets and identify optimization strategies. [Results] Using Beijing's Xicheng District as the study area, the results reveal spatial distribution patterns of vegetation density and sky openness, along with pedestrians' subjective evaluations of indicators such as vegetation diversity and building type. Cluster analysis identified comprehensive service streets centered around Xidan North Street, characteristic streets centered around Xihuangchenggen South Street, and mixed-type streets centered around Lingjing Hutong. [Conclusions] This study innovatively introduces a large language model with human-like perceptual capabilities, enhancing its performance through prompt engineering. The resulting framework enables efficient and integrated evaluation of street visual quality by combining both objective and subjective factors. This approach provides a practical reference for large-scale, automated analysis of street view imagery.

  • QI Haoxuan, CAO Yi, ZHAO Bin
    Journal of Geo-information Science. 2025, 27(3): 623-635. https://doi.org/10.12082/dqxxkx.2025.240707

    [Objectives] The primary objective is to enhance the accuracy of vehicle trajectory prediction at intersections and address the challenges in predicting trajectories in multi-vehicle interaction scenarios. This is crucial for improving the safety and efficiency of autonomous driving and traffic management in complex urban intersections. [Methods] An Enhanced Adjacency Graph Convolutional Network-Transformer (EAG-GCN-T) vehicle trajectory prediction model is developed. The INTERACTION public dataset is employed, with data smoothing techniques applied to mitigate noise. Model comparison and validation experiments are conducted to assess performance. The model’s accuracy is evaluated by comparing error assessment indicators against different baseline models, analyzing interaction capabilities, generalization ability, and driving behavior recognition. The EAG-GCN-T model combines an Enhanced Adjacency Graph Convolutional Network (EAG-GCN) and a Transformer module. The EAG-GCN module accurately models spatial interactions between vehicles by considering relative speed and distance using an enhanced weighted adjacency matrix. The Transformer module captures temporal dependencies and generates future trajectories, improving spatiotemporal prediction ability. [Results] In long-term single-vehicle trajectory prediction, the Average Displacement Error (ADE) and Final Displacement Error (FDE) are reduced by 69.4%, 39.8%, and 33.3% and 71.9%, 32.5%, and 27.4% respectively, compared to CV, ARIMA, and CNN-LSTM models. In multi-vehicle interaction prediction, the FDE is reduced by 19.5% and 20.6% compared to the GRIP model. Compared with three interaction mechanisms, EAG-GCN-T achieves the lowest overall error across all time domains, with ADE/FDE values of 0.53 and 0.74, respectively. EAG-GCN-T achieves more reasonable Driving Area Compliance (DAC) and Trajectory Point Loss Rate (MR), demonstrating strong adaptability in ramps and roundabouts. The model accurately predicts driving behaviors such as following, lane-changing, evasion, and their impacts on trajectories, with predicted trajectories highly consistent with actual vehicle movements. [Conclusions] The EAG-GCN-T model effectively addresses vehicle trajectory prediction in multi-vehicle interaction scenarios at intersections. It demonstrates high accuracy, strong interactivity, and excellent generalization ability. This model provides a novel solution for vehicle trajectory prediction in intelligent transportation systems, offering significant potential for advancing autonomous driving and intelligent traffic management.

  • ZHANG Peng, LIU Wanyue, LIU Chengbao, BO Zheng, NIU Ran, HAN Dongxu, LIN Qian, ZHANG Ziyi, MA Mingze
    Journal of Geo-information Science. 2025, 27(4): 787-800. https://doi.org/10.12082/dqxxkx.2025.240467

    [Significance] The characteristics of the lunar surface, including its mineral compositions, geological formations, environmental factors, and temperature variations, are essential for advancing our understanding of the Moon. These features provide a wealth of scientific data for lunar research, such as resource distribution, environmental characteristics, and evolutionary history. Spectral imagers, which detect mineral compositions in a nondestructive way, play a crucial role in analyzing the mineral compositions of the lunar surface and have become key payloads in scientific exploration missions. With the increasing demand for high-precision lunar exploration data and advancements in spectral imaging technology, there is a growing trend toward acquiring lunar remote sensing data with higher spatial and spectral resolution across a broad spectral range. This trend is shaping the future of lunar orbit exploration, allowing for unprecedented detail in probing the Moon's surface. However, the higher resolution of spatial and spectral data also introduces significant challenges in data processing. [Progress] This paper begins by summarizing existing lunar spectral orbit data, including payload parameters and associated scientific findings. It then explores specific technical challenges in the data processing chain, such as pre-processing and the calculation of lunar surface parameters. Mapping surface compositions through spectral remote sensing is particularly complex due to the mixing of minerals within rocks, which can obscure clear spectral signatures. To address these challenges, various theoretical and empirical approaches have been developed. This paper proposes technical methods and potential solutions to overcome these obstacles.[Conclusions] In conclusion, detailed studies of lunar surface characteristics and the acquisition of high-resolution spectral data are vital for advancing lunar science. Lunar hyperspectral data are expected to support manned lunar exploration and scientific research by enabling the identification of various minerals on the Moon's surface and determining their abundance through hyperspectral observations. Advances in spectral imaging technology and the development of solutions for processing high-resolution data will significantly enhance lunar and planetary science capabilities. These efforts will pave the way for deeper insights into the Moon's geology and potential resource utilization.

  • LI Wangping, WEI Wenbo, LIU Xiaojie, CHAI Chengfu, ZHANG Xueying, ZHOU Zhaoye, ZHANG Xiuxia, HAO Junming, WEI Yuming
    Journal of Geo-information Science. 2025, 27(6): 1448-1461. https://doi.org/10.12082/dqxxkx.2025.250034

    [Objectives] Using deep learning methods for landslide identification can significantly improve efficiency and is of great importance for landslide disaster prevention and mitigation. The DeepLabV3+ algorithm effectively captures multi-scale features, thereby improving image segmentation accuracy, and has been widely used in the segmentation and recognition of remote sensing images. [Methods] We propose an improved model based on DeepLabV3+. First, the Coordinate Attention (CA) mechanism is incorporated into the original model to enhance its feature extraction capabilities. Second, the Atrous Spatial Pyramid Pooling (ASPP) module is replaced with the Dense Atrous Spatial Pyramid Pooling (DenseASPP) module, which helps the network capture more detailed features and expands the receptive field, effectively addressing the limitations of inefficient or ineffective dilated convolution. A Strip Pooling (SP) branch module is added in parallel to allow the backbone network to better leverage long-range dependencies. Finally, the Cascade Feature Fusion (CFF) module is introduced to hierarchically fuse multi-scale features, further improving segmentation accuracy. [Results] Experiments on the Bijie landslide dataset show that, compared with the original model, the improved model achieves a 2.2% increase in MIoU and a 1.2% increase in the F1 score. Compared with other mainstream deep learning models, the proposed model demonstrates higher extraction accuracy. In terms of segmentation quality, it significantly improves the overall accuracy in identifying landslide areas, reduces misclassification and omission, and yields more precise delineation of landslide boundaries. [Conclusions] Based on experiments using the landslide debris flow disaster dataset in Sichuan and surrounding areas, along with practical application verification, the proposed method demonstrates strong recognition capability across landslide images in diverse scenarios and levels of complexity. It performs particularly well in challenging environments such as areas with dense vegetation or proximity to rivers, showing strong generalization ability and broad applicability.

  • XU Wenwen, TANG Xinhua, PAN Shuguo, BAO Yachuan, YU Baoguo
    Journal of Geo-information Science. 2025, 27(3): 612-622. https://doi.org/10.12082/dqxxkx.2024.230532

    [Objectives] The ultra-wideband ranging errors in underground narrow spaces show a significant heavy-tailed distribution. The Gaussian mixture model is more closer to the empirical distribution than a simple Gaussian probability envelope. The Protection Level (PL) obtained through traditional bounding distribution models are overconservative, which reduces system usability. [Methods] To enhance the system usability, an overbounding framework based on Gaussian Mixture Model (GMM) is employed to handle the Time of Arrival (TOA)-based distance measurements obtained from the ultra-wideband ranging system. Firstly, a possibility density function (PDF) of the ranging errors is determined in the form of a dual-component GMM using Expectation-Maximum (EM) algorithm, which provides an approximation of the practical noise distribution in underground space. The PDF plays a crucial role in computing the upcoming overbounding PL. To ensure the mathematical tractability of the overbounding model, the bilateral boundaries of the errors are examined through the use of Cumulative Distribution Function (CDF). Next, in correspondence with the GMM-based PDF model, an asymmetrical CDF is obtained, necessitating the separate overbounding operation on both sides of the CDF. A heuristic adjustment on previous GMM-based PDF is conducted to increase the possibility density of the bilateral tail parts, ensuring sufficient but not excessive space to guarantee the validity of the PL. Initially, on the left side of the CDF, the weight and variance of the Gaussian component with a lower mean value in the GMM-based PDF are increased. Subsequently, the updated PDF will be shifted to the left to create a new version of the GMM-based PDF, with higher values in the left part of the CDF compared to the traditional one. Similar adjustment work needs to be conducted for the right part of the original CDF. After the adjustment operations on both sides, two different GMM-based PDFs can be obtained for every single base station, one is termed as left-boundary PDF while the other is right-boundary PDF. Finally, the predefined PDFs from different UWB base stations will be used to infer the overall PDF in position domain using a convolution operation. Based on this, PL can be computed from the inverse operation of the corresponding CDFs. [Results] In order to verify the methodology, experiments under practical simulated underground scenarios are conducted using six UWB base stations. Error models are constructed using sample data collected within a range of 3 to 93 meters. Evaluation of practical performance shows that the GMM-based bilateral bounding box reduces PL by more than 20% compared to traditional Gaussian-based calculations. [Conclusions] The GMM-based PDF can tighten the PL with a relatively low computational cost, enhancing the system usability.

  • LI Junming, HU Yaxuan, WANG Nannan, WANG Siyaqi, WANG Ruolan, LYU Lin, FANG Ziqing
    Journal of Geo-information Science. 2025, 27(7): 1501-1519. https://doi.org/10.12082/dqxxkx.2025.250161

    [Objectives] Classical statistical inference typically relies on the assumptions of large sample sizes and independent, identically distributed (i.i.d.) observations, conditions that spatio-temporal data frequently violate, leading to inherent theoretical limitations in conventional approaches. In contrast, Bayesian spatio-temporal statistical methods integrate prior knowledge and treat all model parameters as random variables, thereby forming a unified probabilistic inference framework. This enables the incorporation of a broader range of uncertainties and offers robustness in modelling small samples and dependent structures, making Bayesian methods highly advantageous and increasingly influential in spatio-temporal analysis. [Progress] From the perspective of methodological evolution, this paper systematically reviews mainstream Bayesian spatio-temporal statistical models from two complementary perspectives: traditional Bayesian statistics and the Bayesian machine learning. The former includes Bayesian Spatio-temporal Evolutionary Hierarchical Models, Bayesian Spatio-temporal Regression Hierarchical Models, Bayesian Spatial Panel Data Models, Bayesian Geographically Weighted Spatio-temporal Regression Models, Bayesian Spatio-temporal Varying Coefficient Models, and Bayesian Spatio-temporal Meshed Gaussian Process Model. The latter includes Bayesian Causal Forest Models, Bayesian Spatio-temporal Neural Networks, and Bayesian Graph Convolutional Neural Networks. In terms of application, the review highlights representative studies across domains such as public health, environmental sciences, socio-economic and public safety, as well as energy and engineering. [Prospect] Bayesian spatio-temporal statistical methods need to achieve breakthroughs in multi-source heterogeneous data modeling, integration with deep learning, incorporation of causal inference mechanisms, and optimization of high-performance computing. These advances are essential to balance theoretical rigor with practical adaptability and to promote the development of a next-generation spatio-temporal modeling paradigm characterized by causal inference, adaptive generalization, and intelligent analysis.

  • QIN Chengzhi, ZHU Liangjun, CHEN Ziyue, WANG Yijie, WANG Yujing, WU Chenglong, FAN Xingchen, ZHAO Fanghe, REN Yingchao, ZHU Axing, ZHOU Chenghu
    Journal of Geo-information Science. 2025, 27(5): 1027-1040. https://doi.org/10.12082/dqxxkx.2025.240706

    [Objectives] Geographic modeling aims to appropriately couple diverse geographic models and their specific algorithmic implementations to form an effective and executable model workflow for solving specific, unsolved application problems. This approach is highly valuable and in high demand in practice. However, traditional geographic modeling is designed with an execution-oriented approach, which plays a heavy burden on users, especially non-expert users. [Methods] In this position paper, we advocate not only for the necessity of intelligent geographic modeling but also achieving it through a so-called recursive geographic modeling approach. This new approach originates from the user's modeling target, which can be formalized as an initial elemental modeling question. It then reasons backward to resolve the current elemental modeling question and iteratively updates new elemental modeling questions in a recursive manner. This process enables the automatic construction of an appropriate geographic workflow model tailored to the application context of the user's modeling problem, thereby addressing the limitations of traditional geographic modeling. [Progress] Building on this foundational concept, this position paper introduces a series of intelligent geographic modeling methods developed by the authors. These methods aim to reduce the geographic modeling burden on non-expert users while assuring the appropriateness of automatically constructed models. Specifically, each proposed intelligent geographic modeling method is designed to solve a specific type of elemental question within intelligent geographic modeling. The elemental questions include: (1) how to determine the appropriate model algorithm (or its parameter values) within the given application context, (2) how to select the appropriate covariate set as input for a model without a predetermined number of inputs (e.g., a soil mapping model without predetermined environmental covariates as inputs), (3) how to determine the structure of a model that integrates multiple coupled modules (e.g., a watershed system model incorporating diverse process simulation modules), and (4) how to determine the proper spatial extent of input data for a geographic model when a specific area of interest is assigned by the user. The key to solving these elemental questions lies in the effective utilization of geographic modeling knowledge, particularly application-context knowledge. However, since application-context knowledge is typically unsystematic, empirical, and implicit, we developed case formalization and case-based reasoning strategies to integrate this knowledge within the proposed methods. Based on the recursive intelligent geographic modeling approach and the correspondingly methods, we propose an application schema for intelligent geographic modeling and computing. This schema is grounded in domain modeling knowledge, particularly case-based application-context knowledge, and leverages the “Data-Knowledge-Model” tripartite collaboration. A prototype of this approach has been implemented in an intelligent geospatial computing system called EGC (EasyGeoComputing). [Prospect] Finally, this position paper discusses the emerging role of large language models in geographic modeling. Their potential applications, relationships with the research presented here, and prospects for future research directions are explored.

  • SONG Qi, GAO Xiaohong, YIN Chengzhuo, HUANG Yanjun, LI Qiaoli, SONG Yuting, MA Xuyan
    Journal of Geo-information Science. 2025, 27(4): 946-966. https://doi.org/10.12082/dqxxkx.2025.240607

    [Objectives] Unmanned Aerial Vehicle (UAV) and satellite remote sensing technologies have been successfully applied to estimate soil organic carbon and other attributes. However, their application to soil texture estimation remains relatively limited, highlighting the need for further research in this area. This study focuses on three farmland plots located in Zhuozhatan Village (Huzhu County), Nilongkou Village (Lalongkou Town, Huangzhong District), and Baitu Village (Lushar Town, Huangzhong District) within the Huangshui River Basin of Qinghai Province. It explores the potential of UAV and satellite remote sensing technologies for estimating soil texture content at the field scale. [Methods] Using UAV platforms equipped with two hyperspectral cameras, field-scale imaging of farmland soils was conducted. Additionally, a field spectrometer was used to collect in-situ soil spectra, and a total of 838 soil samples were collected from 2022 to 2024. Satellite imagery was also obtained for the same time periods, including GF1/2/7 (Gaofen 1/2/7), Sentinel-2A, and ZY1-02D (Ziyuan 1-02D). Laboratory analyses determined soil particle size distribution and acquired indoor soil spectral data. Based on these datasets, statistical modeling and soil texture content estimation were performed using the XGBoost (Extreme Gradient Boosting) method for laboratory, field in-situ, UAV, GF, ZY1-02D, and Sentinel-2 spectral data. Spatial distribution maps of soil texture content were then generated. [Results] ① Among the XGBoost model results, the highest model accuracy for UAV image spectra achieved an RPD (Ratio of Performance to Deviation) of 2.441, while the optimal RPD values for GF1/2/7, ZY1-02D, and Sentinel-2 satellite imagery were 1.815, 1.601, and 1.561, respectively. ② The estimation accuracy based on UAV and satellite imagery was lower than that derived from field spectrometer measurements. The accuracy ranking was as follows: laboratory spectra > field in-situ spectra > UAV image spectra > GF1/2/7 satellite image spectra > ZY1-02D satellite image spectra > Sentinel-2 satellite image spectra. Among soil texture components, clay content estimation showed the highest accuracy (RPD = 2.70), followed by silt (RPD = 2.24) and sand (RPD = 1.91). ③ Sand and clay content exhibited a negative correlation with soil spectral reflectance, whereas silt content displayed a positive correlation. The sensitive bands for sand, silt, and clay content were primarily concentrated in the near-infrared region (780~2 400 nm). ④ The content of sand, silt, and clay exhibited minor variations over three years, demonstrating relative stability. The mapping results for the three plots showed soil texture contents predominantly in the following ranges: 67% < sand ≤ 83%, 10.6% < silt ≤ 19.1%, and 3.2% < clay ≤ 6.6%. [Conclusions] At the field scale, UAV imagery was identified as the most effective data source for soil texture content mapping, providing strong support for precision agricultural management. While GF1/2/7 and ZY1-02D satellite imagery were found to be sufficient for texture mapping, Sentinel-2 satellite imagery was too coarse for field-scale mapping.

  • HE Li, WANG Rong
    Journal of Geo-information Science. 2025, 27(9): 2151-2164. https://doi.org/10.12082/dqxxkx.2025.250273

    [Significance] Space is not merely a physical place, but a productive arena of social relations. Social phenomena are inherently endowed with spatial attributes, making the spatial perspective a critical pathway for understanding complex social issues. With the deepening "spatial turn" in the social sciences and continuous advancements in Geographic Information Systems (GIS)—particularly in data acquisition, spatial analysis and modeling, and spatial visualization—GIS has become an essential tool for addressing social issues. However, disciplinary differences in theoretical paradigms, methodological logic, and scale cognition between geography and the social sciences constrain their deeper integration. Existing literature lacks a systematic synthesis of integration trends, underlying challenges, and empowerment pathways, necessitating a comprehensive clarification of fusion mechanisms, core obstacles, and emerging opportunities. [Progress] This paper identifies five key advantages of GIS in empowering social science research: expanding spatial analytical thinking, supporting spatiotemporal data, enhancing survey techniques, enriching representational forms, and strengthening analytical capabilities. We review representative GIS applications in economics, political science, and sociology. From dimensions such as spatial cognition, data capacity, methodological adoption, and research hotspots, we distill application characteristics across these disciplines, revealing both commonalities and differences. While all three disciplines recognize spatial effects, their theoretical orientations shape distinct technical approaches—economics emphasizes causal identification, political science focuses on geopolitical structures, and sociology prioritizes contextual representation. Through a three-dimensional analysis—data, methodology, and cognition—we examine three major challenges in addressing social issues: the mismatch between data and research questions, the difficulty of integrating methods with causal mechanisms, and the contextual misalignment of place and scale, which reflect deeper issues of data suitability, methodological coherence, and the validity of spatial reasoning. [Prospects] The advancement of artificial intelligence, especially large models, injects new methodological momentum into GIS-based spatial analysis and brings threefold opportunities for addressing social issues. First, large models are driving spatial analysis from correlation-based description toward transparent causal inference; Second, multi-source data fusion and the generation of "silicon-based samples" help overcome the limitations of traditional survey data. Third, an emerging "space-survey" integrated framework is constructing a "spatial cognitive infrastructure" to support social research. Future efforts should establish a synergistic "large model-spatial analysis" paradigm that integrates these three opportunities. By simultaneously addressing challenges of data matching, method integration, and contextual misalignment, this paradigm can elevate GIS from a supportive tool to a core engine for theory generation and mechanism interpretation. This transformation will enhance the scientific value and practical effectiveness of GIS and spatial analysis in addressing complex social issues, fostering a bidirectional interaction between methodological innovation and theoretical advancement.

  • LIU Chengbao, BO Zheng, ZHANG Peng, ZHOU Miyu, LIU Wanyue, HUANG Rong, NIU Ran, YE Zhen, YANG Hanzhe, LIU Shijie, HAN Dongxu, LIN Qian
    Journal of Geo-information Science. 2025, 27(4): 801-819. https://doi.org/10.12082/dqxxkx.2025.240466

    [Significance] Lunar remote sensing is a critical method to ensure the safety and success of lunar exploration missions while advancing lunar scientific research. It plays a significant role in understanding the Moon's geological evolution and the formation of the Earth-Moon system. Accurate lunar topographic maps are essential for mission planning, including landing site selection, navigation, and resource identification. These maps also provide valuable data for studying planetary processes and the history of the solar system. [Progress] In recent years, with growing global interest and investment in lunar exploration, remarkable progress has been made in remote sensing technology. These advancements have significantly improved the precision, resolution, and coverage of lunar topographic mapping. Various lunar remote sensing missions, such as China's Chang'e program, NASA's Lunar Reconnaissance Orbiter, and missions by other space agencies, have acquired substantial amounts of multi-source, multi-modal, and multi-scale data. This wealth of data has laid a solid foundation for technological breakthroughs. For instance, high-resolution laser altimetry, optical photogrammetry, and synthetic aperture radar have provided detailed datasets, enabling refined mapping of the Moon's surface. However, the dramatic increase in data volume, complexity, and heterogeneity presents challenges for effective processing, integration, and application in topographic mapping. This paper provides a comprehensive overview of the current state of lunar topographic remote sensing and mapping, focusing on the implementation and data acquisition capabilities of major lunar remote sensing missions during the second wave of lunar exploration. It systematically summarizes the latest research progress in key surveying and mapping technologies, including laser altimetry, which enables precise elevation measurements; optical photogrammetry, which reconstructs surface features using high-resolution imagery; and synthetic aperture radar, which provides unique insights into topographic and subsurface structures. [Prospect] In addition to reviewing recent advancements, the paper discusses future trends and challenges in the field. Key recommendations include enhancing sensor functionality and performance metrics to improve data quality, optimizing the lunar absolute reference framework for consistency and accuracy, leveraging multi-source data fusion for fine-scale modeling, expanding scientific applications of lunar topography, and developing intelligent and efficient methods to process massive amounts of remote sensing data. These efforts will not only support upcoming lunar exploration missions, such as China's manned lunar landing program scheduled for 2030, but also contribute to a deeper understanding of the Moon and its relationship with Earth.

  • LIU Chang, SHI Erpeng, GUO Shiyi, GUO Liang, SUN Xiaoli
    Journal of Geo-information Science. 2025, 27(3): 585-600. https://doi.org/10.12082/dqxxkx.2024.230576

    [Objectives] Urban public transportation service quality is an important factor affecting residents' travel choices and quality of life, but the current development and reform of urban public transportation in China still has shortcomings, and it is necessary to incorporate public perception into the decision-making basis and improve service quality from the perspective of residents. Previous studies have two main limitations: first, they rely on traditional analysis methods based on traffic surveys, which fail to capture the regional differences in perceived service quality; second, they use big data from social media platforms, which are prone to information bias, polarization, and other issues, and do not reflect the public's real needs. Moreover, they mostly focus on public opinion analysis, without providing specific and feasible optimization paths. [Methods] To address these gaps, this paper proposes a method that combines public network participation and semantic analysis. It uses internet big data to extract online messages related to urban public transportation from the online interactive platform between government and citizens and analyzes their spatiotemporal features and perceived service quality. It also conducts spatial analysis and explores the service efficiency of the public transportation system in relation to the transportation facility distribution. Based on this, it offers optimization suggestions. The paper selects Wuhan as a case study, which is one of the national central cities and an important megacity in the middle reaches of the Yangtze River. The urban development area in Wuhan is a key zone for urbanization and a major hub for public travel activities, covering 15 functional zones. It has a complete public transportation facility allocation, including all the subway lines and stations, and most of the bus lines and stations in the city. [Results] The main findings are as follows: (1) The quality of public network participation data can reflect the spatiotemporal patterns of actual travel activities and has high credibility; (2) The emotional expression of the public varies across individuals and regions and the perceived service quality dimensions can be categorized into five topics: "public transportation planning and construction", "public transportation travel conditions", "residential community bus configuration", "public transportation route setting", and "public transportation operation service". Furthermore, the perceived service quality exhibits spatial imbalance and agglomeration; (3) Corresponding optimization suggestions are made for the road system in the main urban area, subway stations in the far urban area, and bus routes at the junction of the main urban area and far urban area. [Conclusions] The research results of this paper provide a new method for fine-grained identification and optimization of spatial differences in urban public transportation perceived service quality, and also demonstrate the application value of public network participation data in facilitating government decision-making.

  • WENG Mingkai, XIAO Guirong
    Journal of Geo-information Science. 2025, 27(5): 1113-1128. https://doi.org/10.12082/dqxxkx.2025.250050

    [Objectives] The quality of training samples significantly impacts model performance and prediction accuracy. In regions with limited sample data, the small number of samples and their uneven spatial distribution may prevent the model from effectively learning the features of disaster-inducing factors. This increases the risk of overfitting and ultimately affects the accuracy of model predictions. Therefore, it is crucial to collect and optimize training samples based on regional characteristics. [Methods] To address this issue, this study proposes a sampling optimization method for training samples. The method combines the Prototype Sampling (PBS) approach for selecting landslide-positive samples with an unsupervised clustering model for training sample selection. This results in a screened and expanded positive sample dataset and an objectively extracted negative sample dataset, forming an optimized training sample dataset. Subsequently, the Random Forest (RF) and Support Vector Machine (SVM) models, which are well suited for handling small sample data, were employed to construct a landslide susceptibility evaluation model. Comparative experiments were conducted using Raw Data (RD), a dataset with only Data Augmentation (DA), and the optimized dataset. Model prediction performance was assessed using metrics such as the Area Under the Curve (AUC). Additionally, the frequency ratio method was applied to optimize the results of landslide susceptibility zoning. Finally, a case study was conducted in Putian City, where landslide sample data is relatively scarce, to verify the effectiveness and generalization capability of the proposed sampling optimization method. [Results] The results indicate that models trained on the SO dataset achieved AUC improvements of 10.69% and 18.23% compared to those trained on the RD and DA datasets, respectively, demonstrating a significant enhancement in predictive performance. This suggests that selecting and expanding positive samples while objectively extracting negative samples can improve model accuracy and mitigate the overfitting problem during training. Furthermore, the frequency ratio analysis revealed that the SO-RF model achieved higher frequency ratios in regions with extremely high and high susceptibility than the SO-SVM model, indicating that SO-RF is more suitable for evaluating landslide susceptibility in regions with limited landslide sample data, such as Putian City. [Conclusions] The proposed training sample optimization approach, combined with machine learning evaluation methods, demonstrates high applicability and accuracy. Therefore, the findings of this study provide valuable insights into machine learning-based sampling strategies for landslide susceptibility assessment.

  • DING Yan, MA Yaohong, WANG Jiale, LI Yunhao, CHEN Biyu
    Journal of Geo-information Science. 2025, 27(3): 653-667. https://doi.org/10.12082/dqxxkx.2025.240639

    [Objectives] Accurate and reliable traffic state prediction is essential for various applications in Intelligent Transportation Systems (ITS). However, the complexity of urban road networks makes it challenging to effectively model spatial dependencies between road segments, posing a significant obstacle to urban traffic forecasting. Traditional Graph Convolutional Networks (GCNs) are widely used for traffic prediction but fail to account for the unique characteristics of traffic networks, such as driving directions, turning rules, and varying spatial dependencies. This study aims to address these challenges by proposing a novel graph convolutional network model, the Turn-based Graph Convolutional Neural Network (TurnGCN), which better captures the complex spatial relationships in urban traffic networks. [Methods] TurnGCN models the urban road network as a heterogeneous graph, where edges represent turning relationships between road segments. Unlike traditional GCNs that rely on static adjacency matrices, TurnGCN introduces a turning table to label neighboring nodes and map their features into a structured Euclidean feature grid. A Convolutional Neural Network (CNN) is then applied to this grid to aggregate and fuse the spatial features of neighboring nodes. This approach allows TurnGCN to model the heterogeneity of turning relationships and learn their varying impacts on the central road segment. Additionally, the parameter-sharing nature of CNNs ensures that TurnGCN performs efficiently with relatively fewer trainable parameters. [Results] To validate the effectiveness of TurnGCN, extensive experiments were conducted on two real-world traffic datasets: Urban-150 from Seoul, South Korea, and SHSpeed from Shanghai, China. These datasets vary in sampling density and temporal resolution, presenting diverse evaluation challenges. The results demonstrate that TurnGCN consistently outperforms traditional GCNs and GCN variants enhanced with spatial attention mechanisms across multiple evaluation metrics. Specifically, TurnGCN excels in capturing heterogeneous spatial dependencies and modeling turning relationships in urban road networks. [Conclusions] TurnGCN provides a robust, efficient, and scalable solution for urban traffic prediction by explicitly modeling turn-based spatial relationships. It overcomes the limitations of traditional GCNs and attention-based models, achieving significant improvements in predictive performance while maintaining computational efficiency. These advantages highlight TurnGCN’s potential for practical applications in ITS, including traffic flow optimization, congestion management, and intelligent navigation systems.

  • ZHAO Jinzhao, WEI Zhicheng
    Journal of Geo-information Science. 2025, 27(3): 682-697. https://doi.org/10.12082/dqxxkx.2025.240621

    [Objectives] City-wide traffic flow prediction plays a crucial role in intelligent transportation systems. Traditional studies partition road networks into grids, represent them as graph structures with grids as nodes, and use graph neural networks for region-level prediction. However, this region-based approach overlooks the relationships between individual roads, making it difficult to reflect traffic flow changes of roads. Methods based on road segment data can better capture spatial connections between roads and enable more accurate traffic flow predictions. However, mapping trajectory data to roads presents challenges such as redundant data and trajectory mismatches, and traffic flow data after mapping is sparse. Existing methods struggle to effectively capture the spatial correlation in sparse traffic conditions. [Methods] To address these issues, this study proposes an Attention Spatio-Temporal Neural Network (ASTNN) model for road-level sparse traffic flow prediction. The model first preprocesses trajectory data and applies Hidden Markov Model (HMM)-based map matching to obtain road-level traffic flow data. It then introduces an adaptive compact 2D image representation method to model the road network as a 2D image, where road segments are represented as pixel points. Based on an analysis of the spatial and temporal characteristics of traffic flow, two new attentional spatiotemporal blocks are proposed: Attentional Spatio-Temporal Memory Block (ASTM block) for mining temporal correlations and attentional spatial-temporal focusing block (ASTF block) for extracting spatial sparse features. By integrating these two blocks with external information, ASTNN is constructed to achieve road-level traffic flow prediction. [Results] This study uses Chengdu taxi trajectory data as a case study. After preprocessing trajectory data and mapping traffic flow, the proposed model is validated on a five-level road network within Chengdu’s third ring area. Results indicate that the proposed data processing method reduces trajectory-to-road network matching time by 73.6%. In the comparative experiments with existing models, such as Convolutional Neural Network (CNN), Convolutional Long Short-Term Memory (ConvLSTM), Gated Recurrent Unit (GRU), and Spatial-Temporal Neural Network (STNN), ASTNN achieves the highest prediction accuracy in terms of Root Mean Square Error (RMSE), Mean Absolute Error (MAE), and R-squared (R2). Furthermore, the study confirms the significant improvement in prediction accuracy when incorporating temperature data into ASTNN, providing new insights for optimizing model performance. [Conclusions] The ASTNN model proposed in this study provides an effective framework for city-wide, road-level sparse traffic flow prediction, offering valuable insights for intelligent transportation systems.

  • MA Qiwei, HUANG Jingxiong, LIU Anqi, DANG Anrong
    Journal of Geo-information Science. 2025, 27(3): 668-681. https://doi.org/10.12082/dqxxkx.2024.240001

    [Objectives] Polycentric spatial strategies have emerged as effective solutions to urban challenges such as prolonged commuting, traffic congestion, air pollution, and environmental degradation. These strategies, widely implemented in Chinese cities, require robust evaluation to enhance the efficacy of urban spatial development policies. Traditional research approaches often combine quantitative and qualitative methods or develop evaluative indicators, yet they may lack explicit, measurable goals, and benchmarks, leading to reliance on empirical judgment. This can limit their practical application in directing the future development and investments for urban centers, subsequently affecting urban governance support. [Methods] To addressing these gaps, this study introduces a comprehensive technical framework that employs multiple machine learning models. Its primary aim is to delineate the optimal polycentric structure for a city by contrasting it with the present spatial distribution of employment centers. This comparative analysis enables a more empirical assessment of urban spatial strategy performance. Central to this framework is the goal of minimizing the city's average commuting distance, a metric significantly influenced by the urban spatial structure and commonly used in urban structure assessment. The study unfolds in several stages: initially, it utilizes a probabilistic mixture model to identify the urban polycentric structure and gauge the influence of individual centers. It then employs machine learning to investigate the non-linear interplay between urban employment centers, residential/occupational patterns, and commuting flows. Subsequently, an intelligent optimization algorithm calculates the optimal polycentric structure with the aim of minimizing commuting distances. The study culminates in the development of performance evaluation indices that quantitatively measure the urban spatial structure's current state against the ideal, highlighting avenues for future optimization. [Results] Empirical evaluation is conducted across the central urban zones of thirteen prefecture-level cities within the Beijing-Tianjin-Hebei metropolitan region, yielding three principal findings. First, each city exhibits a distinct polycentric structure, with primary employment centers situated centrally within municipal districts and secondary centers dispersed in the periphery. Second, the optimization results indicate a general trend of decentralization, with a movement from city centers to the periphery. Third, cluster analysis categorizes the cities into four groups, with strategic recommendations provided for each group, largely aligning with existing local government urban and spatial plans. [Conclusions] This study's contributions are multifaceted. It proposes a methodology for ascertaining the optimal polycentric pattern, thus creating a standard for performance evaluation and enabling quantifiable assessments. It offers a comprehensive method for assessing the execution of urban polycentric spatial strategies and evaluating the intricacy of the city's polycentric structure. Finally, the application of these methods in the Beijing-Tianjin-Hebei region provides analytical outcomes that are instrumental for the future urban refinement governance of the area.

  • PING Yifan, LU Jun, GUO Haitao, HOU Qingfeng, ZHU Kun, SANG Zehao, LIU Tong
    Journal of Geo-information Science. 2025, 27(7): 1608-1623. https://doi.org/10.12082/dqxxkx.2025.250051

    [Objectives] Cross-view image geolocation refers to a technology that determines the geographical location of an image by matching it with reference images taken from different perspectives and possessing precise location information. This technology plays a crucial role in real-world applications such as Unmanned Aerial Vehicle (UAV) navigation, environmental monitoring, and target positioning. Currently, most deep learning-based cross-view image retrieval and geolocation methods for drone-satellite tasks rely heavily on supervised learning. However, the scarcity of high-quality labeled data presents a significant limitation, hindering the generalization capability of these models. Moreover, existing methods often fail to effectively model the spatial layout of images, making it difficult to bridge the substantial domain gap between cross-view images, thereby limiting the accuracy and robustness of geolocation tasks. [Methods] To address these challenges, this paper proposes a novel cross-view image retrieval and localization architecture called DINO-MSRA. The architecture first employs the DINOv2 large model framework, fine-tuned by Conv-LoRA, as the feature encoder. This enhances the model's feature extraction capabilities with fewer parameters, improving both efficiency and accuracy. Second, we design a spatial relation-aware feature aggregator based on the Mamba module (MSRA) to more effectively aggregate image features. By embedding spatial configuration features into the global descriptor, this module significantly improves the model's performance in cross-view matching tasks, especially in complex scenarios where spatial relationships between objects are crucial. Finally, the InfoNCE loss function is adopted to train the model, optimizing contrastive learning and ensuring more accurate retrieval and localization results. [Results] Extensive comparative and ablation experiments were conducted on the University-1652 and SUES-200 datasets. The experimental results show that for drone-view target localization (drone→satellite) and drone navigation (satellite→drone) tasks, the proposed method achieves R@1 accuracies of 95.14% and 97.29%, respectively, on the University-1652 dataset, representing improvements of 0.68% and 1.14% over the current best algorithm, CAMP. On the SUES-200 dataset at an altitude of 150 meters, R@1 accuracies reach 97.2% and 98.75%, which are 1.8% and 2.5% higher than CAMP, respectively. Moreover, the proposed method requires significantly fewer parameters than existing algorithms, only 19.2% of those used by Sample4Geo. [Conclusions] In summary, the proposed DINO-MSRA architecture outperforms current state-of-the-art methods in cross-view image matching, achieving higher accuracy and faster inference speed. These results demonstrate its robustness and practical application potential in challenging real-world scenarios.

  • YU Hanyang, LAN Chaozhen, WANG Longhao, WEI Zijun, GAO Tian, WANG Yiqiao, LIU Ruimeng
    Journal of Geo-information Science. 2025, 27(8): 1896-1919. https://doi.org/10.12082/dqxxkx.2025.250052

    [Significance] Multimodal remote sensing image matching has become a fundamental task in integrated Earth observation, enabling precise spatial alignment across heterogeneous image sources. [Progress] As the diversity of sensing modalities, acquisition geometries, and temporal conditions increases, traditional matching frameworks have proven inadequate for capturing complex variations in radiometric responses, geometric configurations, and semantic representations. This technological gap has driven a significant paradigm shift from handcrafted feature engineering to deep learning-based solutions, which now form the core of current research and application development. This paper provides a comprehensive and structured review of recent advances in deep learning methods for multimodal remote sensing image matching, with an emphasis on the evolution of methodological paradigms and technical frameworks. It establishes a clear dual-path classification: the single-session approach and the end-to-end approach. The former selectively replaces or enhances individual components of traditional pipelines, such as feature encoding or similarity estimation, using neural network modules. The latter integrates the entire matching process into a unified network architecture, enabling joint optimization of feature learning, transformation modeling, and correspondence inference within a closed loop. This progression reflects the field's transition from modular adaptation to holistic modeling, revealing a deeper integration of data-driven representation learning with geometric reasoning. The review further examines the development of architectural strategies supporting this evolution, including attention mechanisms, graph-based structures, hierarchical feature fusion, and modality-bridging transformations. These innovations contribute to improved robustness, semantic consistency, and adaptability across diverse matching scenarios. Recent trends also demonstrate a growing reliance on pretrained vision foundation models, which provide transferable feature spaces and reduce the dependence on large-scale labeled datasets. In addition to summarizing technical advancements, the paper analyzes representative datasets, performance evaluation strategies, and the current challenges that constrain real-world deployment. These include limited data availability, weak cross-scene generalization, computational inefficiency, and insufficient interpretability. [Prospect] By synthesizing methodological progress with practical demands, the review identifies key directions for future research, including the design of modality-invariant representations, physically-informed neural architectures, and lightweight solutions tailored for scalable, real-time image registration in complex operational environments.

  • SU Zhiping, YANG Chengsheng, WANG Ziqian
    Journal of Geo-information Science. 2025, 27(4): 979-993. https://doi.org/10.12082/dqxxkx.2025.240614

    [Objectives] The influence of negative sample selection and machine learning models on landslide susceptibility evaluation cannot be overlooked. [Methods] To investigate the impact of these two factors on landslide susceptibility assessment, this study examines the Nujiang Valley section of the Nujiang River Basin. A weighted information quantity model was proposed to optimize negative sample selection. Thirteen influencing factors, including topography, land use, and average annual rainfall, were selected. Three machine learning models were employed: Support Vector Machine (SVM), Convolutional Neural Network (CNN), and Gradient Boosting Decision Tree (GBDT). A comparative analysis of landslide susceptibility was conducted against traditional random sample selection methods. Additionally, the effect of rainfall factors on susceptibility classification was analyzed. [Results] The results indicate that: (1) The optimized negative sample selection improved landslide density by 0.0103, 0.0639, and 0.004 0, respectively, for the three models. The AUC values increased by 0.033, 0.018, and 0.008, respectively. (2) Among the susceptibility evaluation models, the GBDT model performed best, improving accuracy by 3.8% and 1.7% compared to the SVM and CNN models, respectively. (3) Incorporating average monthly rainfall data for summer and winter (2019—2020) into the GBDT model revealed an increase in high and relatively high susceptibility zones during summer, particularly in the southern regions of Liuku Town and Shangjiang Town. [Conclusions] The optimization of negative samples based on the weighted information quantity model is reasonable and effective. As a landslide susceptibility evaluation model, the GBDT model is the most suitable for the disaster-prone environment of the Nujiang Valley, where precipitation significantly impacts landslide susceptibility.

  • XIN Rui, YANG Kuan, WANG Jiaoe
    Journal of Geo-information Science. 2025, 27(3): 570-584. https://doi.org/10.12082/dqxxkx.2024.240339

    [Objectives] Understanding the spatial and temporal characteristics of different types of taxis operations is crucial for transport planning and management. In this paper, a novel research model, Taxi Mobility Chain (TMC), is constructed by stringing together consecutive movements of individual taxis using order data from traditional taxis and e-hailing cars in Xiamen City. The introduction of TMC addresses the limitation of traditional research that uses isolated OD flow as the analysis unit to some extent, and provides richer background information, which can connect with more intelligent methods and has better universality. [Methods] Based on the obtained TMCs, we designed corresponding indicators as analytical tools from the dimensions of taxi usage and TMC characteristics. These tools are used for the macroscopic description of the usage of traditional taxis and e-hailing cars and the quantitative computation of the spatial morphological characteristics of TMCs. In particular, with reference to the word embedding technology in the field of Natural Language Processing (NLP), we explore the spatiotemporal pattern characteristics formed during taxi operations by using clustering algorithms after embedding the cellular areas of the study area grid. [Results] By comparing and analyzing two kinds of taxis with different operation modes ("vehicles looking for people" and "people looking for vehicles"), the results of the indicator analysis module mainly indicate that the average daily number of orders received by a single taxi does not differ much between weekdays and non-weekdays, and the individual utilization rate is relatively stable. However, the drivers of traditional taxis have more autonomy in taking orders, more consecutive orders, and higher work intensity. The results of the cluster analysis module mainly indicate that traditional taxi operations show stronger aggregation and are more inclined to shuttle back and forth in some hotspots. E-hailing cars are based on individual travelling needs, with boarding and alighting points completely decided by passengers, resulting in a larger spatial service scope. In addition, when the number of clusters is equal to 2, the clustering results do not differ much between weekdays and non-weekdays, and roughly correspond to the primary and secondary operation areas of the two types of taxis. When the number of clusters is equal to 6, traditional taxis with higher autonomy are clustered in high outbound travel demand areas on non-weekdays. The overall clustering results of traditional taxis are more correlated with the spatial distribution of the high-density road network, while the clustering results of e-hailing cars are more correlated with administrative districts. As the number of clusters increases from 2 to 18, the clustering characteristics of traditional taxis operations become more prominent. [Conclusions] Using TMC-based cluster analysis tools, the thesis can better identify the spatiotemporal characteristics of taxi operations and reveal the status and role of different types of taxis in urban transport.

  • WANG Kuang, KE Rihong, LI Shengnan, WANG Pu
    Journal of Geo-information Science. 2025, 27(4): 967-978. https://doi.org/10.12082/dqxxkx.2025.240586

    [Objectives] Revealing the structural characteristics of tourist flow networks is a prerequisite for achieving complementary advantages and coordinated development among attractions.[Methods] In this study, we employs methods such as travel chain extraction, social network analysis, and community detection to construct a research framework to analyze multi-scale tourist flow networks based on large-scale mobile phone data. The structural characteristics of the tourist flow network in Changsha are explored at microscopic, mesoscopic, and macroscopic scales.[Results] (1) Microscopic scale: The tourist flow network of Changsha shows a significant centralization trend, where a few core attractions such as the Yuelu Mountain and Orange Island have great influences on the whole network. Only 33% of attractions show structural hole efficiency and effectiveness above average, while their constraint is below average, indicating prominent structural holes and limited overall connectivity and efficiency. (2) Mesoscopic scale: The tourist flows of Changsha are highly concentrated, showing obvious spatial clustering characteristics and forming six tourism communities. There are usually two core attractions in each community to drive tourists to visit the surrounding attractions. In addition, the development of tourism communities is unbalanced, with a highly large community centered on Yuelu Mountain and Orange Island. (3) Macroscopic scale: The spatial distribution of the tourist flow network presents the characteristics of single-core strong concentration and overall dispersion, showing a multi-layer structure with the city center as the core and spreading outwards. The global efficiency of the network is only 0.367, with some marginal attractions having poor accessibility. The core attraction plays limited "trickle-down" effects on marginal attractions.

  • LI Pengshuo, FENG Yongjiu, TONG Xiaohua, XI Mengrong, XU Xiong, LIU Shijie, HUANG Qian
    Journal of Geo-information Science. 2025, 27(4): 864-875. https://doi.org/10.12082/dqxxkx.2025.240401

    [Objectives] Rovers play an essential role in lunar exploration, serving as vital tools for scientists aiming to unravel the Moon's geological history and exploit its potential water-ice reserves. However, navigating the lunar surface with rovers presents significant safety risks due to the complex and often hazardous terrain, compounded by the lack of a consistent and reliable light source. The absence of pre-existing, high-resolution data—such as LiDAR—prior to exploration missions poses a considerable challenge in evaluating the safety of potential rover paths. Given these constraints, developing a reliable pre-assessment method is crucial for enhancing the success rate of lunar rover missions. [Methods] This paper introduces a 3D simulation method for lunar rover exploration, leveraging the Visualization Toolkit (VTK) to address these challenges. Our method integrates three critical aspects. Firstly, it offers high-resolution visualization of the lunar surface terrain, capturing intricate details down to the meter scale. Secondly, it simulates the dynamic illumination environment on the lunar surface, accounting for the varying illumination conditions due to the Moon 's rotation and orbital position. Thirdly, it models the rover's position and attitude transformations as it navigates the terrain. [Results] The effectiveness of this simulation approach is demonstrated through a case study focusing on the Shackleton Connecting Ridge region at the lunar South Pole, an area of significant interest due to its challenging topography and potential for water-ice deposits. The 3D simulation accurately depicts the undulating terrain of impact craters and allows for a thorough assessment of the rover's route safety by visualizing the potential hazards along the path. Moreover, the simulation offers an intuitive representation of the rover's movement, including real-time adjustments in position and attitude, which are critical for ensuring the rover’s stability and operational safety over long distances. Additionally, our method includes a real-time update feature for the dynamic illumination scene, enabling direct observation of how changing light conditions affect the rover's path during the mission. This capability is particularly important for assessing the feasibility of navigating through areas that may experience prolonged periods of darkness or extreme shadowing, which could impede the rover's progress or jeopardize its safety. The goal of this research is to improve the reliability and safety of future lunar rover missions by providing a robust pre-assessment tool that can verify the feasibility of proposed exploration routes. [Conclusions] This method thus offers crucial a priori information, serving as an essential guarantee for the successful execution of future lunar exploration endeavors.

  • Journal of Geo-information Science. 2025, 27(4): 785-786.