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International Journal of Digital Earth 2020年第9期13卷 976-997页

作者： Weiming Huang Lars Harrie Department of Physical Geography and Ecosystem Science Lund UniversityLundSweden

Geovisualisation is a knowledge-intensive art in which both providers and users need to possess a wide range of knowledge.Current syntactic approaches to presenting visualisation information lack semantics on the one hand,and on the other hand are too bespoke.Such limitations impede the transfer,interpretation,and reuse of the geovisualisation knowledge.In this paper,we propose a knowledge-based approach to formally represent geovisualisation knowledge in a semantically-enriched and machine-readable manner using Semantic Web technologies.Specifically,we represent knowledge regarding cartographic scale,data portrayal and geometry source,which are three key aspects of geovisualisation in the contemporary web mapping era,coupling ontologies and semantic rules.The knowledge base enables inference for deriving the corresponding geometries and portrayals for visualisation under different conditions.A prototype system is developed in which geospatial linked data are used as underlying data,and some geovisualisation knowledge is formalised into a knowledge base to visualise the data and provide rich semantics to users.The proposed approach can partially form the foundation for the vision of web of knowledge for geovisualisation.

关键词： Geovisuaisation Semantic Web knowledge representation ontologies semantic rules

Examining El Nio in the Holocene: implications and challenges

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National science Review 2018年第6期5卷 807-809页

作者： Zhengyao Lu Zhengyu Liu Department of Physical Geography and Ecosystem Science Lund University department of geography Ohio State University

The El Nio–Southern Oscillation(ENSO) is characterized by year-to-year anomalous surface climate variability over the tropical Pacific. Through atmospheric teleconnections, ENSO can bring droughts and floods worldw... 详细信息

关键词： Examining El Ni implications and challenges o in the Holocene El

Matching authority and VGI road networks using an extended node-based matching algorithm

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Geo-Spatial Information science 2015年第2期18卷 65-80页

作者： Ehsan ABDOLMAJIDI Ali MANSOURIAN Julian WILL Lars HARRIE GIS Center Department of Physical Geography and Ecosystem ScienceLund UniversitySölvegatan 1222362 LundSweden

The amount of volunteered geographic information(VGI)has increased over the past decade,and several studies have been conducted to evaluate the quality of VGI data.In this study,we evaluate the completeness of the road network in the VGI data set OpenStreetMap(OSM).The evaluation is based on an accurate and efficient network-matching algorithm.The study begins with a comparison of the two main strategies for network matching:segment-based and nodebased matching.The comparison shows that the result quality is comparable for the two strategies,but the node-based result is considerably more computationally efficient.Therefore,we improve the accuracy of node-based algorithm by handling topological relationships and detecting patterns of complicated network components.Finally,we conduct a case study on the extended node-based algorithm in which we match OSM to the Swedish National Road Database(NVDB)in Scania,Sweden.The case study reveals that OSM has a completeness of 87%in the urban areas and 69%in the rural areas of Scania.The accuracy of the matching process is approximately 95%.The conclusion is that the extended node-based algorithm is sufficiently accurate and efficient for conducting surveys of the quality of OSM and other VGI road data sets in large geographic regions.

关键词： geographic data volunteered geographic information(VGI) OpenStreetMap(OSM) node-based matching segment-based matching pattern detection Swedish National Road Database(NVDB)

Climate change and land degradation in Africa: a case study in the Mount Elgon region, Uganda

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Geo-Spatial Information science 2014年第1期17卷 39-53页

作者： Boyi JIANG Yazidhi BAMUTAZE Petter PILESJO Department of Physical Geography and Ecosystem Science GIS CentreLund UniversityLundSweden department of geography Geo-Informatics and Climatic SciencesCollege of Agricultural and Environmental Sciences(MCAES)Makerere UniversityKampalaUganda

The aim of this study is to estimate and compare soil erosion,in the Mount Elgon region,eastern Uganda,during the last decade.Possible trends and changes in erosion are linked to precipitation/climate change as well as changes in land cover.Two different versions of the Revised Universal Soil loss Equation(RUSLE)are implemented and compared,one using slope length and the other using flow accumulation to estimate the slope length and steepness factor(LS).Comparisons of the modeled soil erosion vs.field data indicate that RUSLE based on flow accumulation is preferable.The modeling is carried out for the years 2000,2006,and 2012,and is based on ASTER remotely sensed data,digital elevation models,precipitation data from the study area,as well as existing soil maps.No significant trends in estimated soil erosion are found to be present during the last decade.Over exploitation of land is probably compensated by improved agricultural management and no significant increase in precipitation.Even if there are reports of more intense and increasing amounts of rainfall in the area,this could not be verified,neither through the analysis of climate data,nor by trends in the estimated soil loss.

关键词： soil erosion revised universal soil loss equation(RUSLE) ASTER Uganda climate change

Monitoring multi-temporal changes of lakes on the Tibetan Plateau using multi-source remote sensing data from 1992 to 2019: A case study of Lake Zhari Namco

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Journal of Earth science 2022年

作者： Juan Wu Chang-Qing Ke Yu Cai Zheng Duan Jiangsu Provincial Key Laboratory of Geographic Information science and Technology， Key Laboratory for Land Satellite Remote Sensing Applications of Ministry of Natural Resources， School of geography and Ocean science， Nanjing University Collaborative Innovation Center of Novel Software Technology and Industrialization Collaborative Innovation Center of South China Sea Studies Department of Physical Geography and Ecosystem Science， Lund University

Lake level， area and volume are sensitive indicators of climate change. At present， many studies have focused on the interannual water balance of lakes， but lake level and area can change remarkably with seasons， especially for lakes with seasonal ice cover. Zhari Namco， a seasonal frozen lake， was selected as an example to investigate its seasonal water balance. Multi-source altimetry and Landsat data were used to obtain the seasonal lake level and area from 1992 to 2019， and seasonal lake volume variations were also estimated. The results indicated the average lake level， area and volume in autumn were the largest. The lake level， area， and volume experienced three turning points approximately in 2000， 2010， and 2016， and showed an overall increasing trend from 1992 to 2019， with slopes of 0.15 m/year， 2.17 km;/year， and 0.14 km;/year， respectively. The lake area expanded significantly in autumn， which was related to the abundant precipitation. Delay time of land surface runoff， increased temperature， and evaporation may be the reason for the low lake level and volume in summer. The precipitation was the dominant factor of water balance， which explained 62.09%， 62.43%， and 62.10% of the variations in lake level， area， and volume， respectively.

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A graph autoencoder network to measure the geometric similarity of drainage networks in scaling transformation

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International Journal of Digital Earth 2023年第1期16卷 1828-1852页

作者： Huafei Yu Tinghua Ai Min Yang Weiming Huang Lars Harrie School of Resource and Environmental sciences Wuhan UniversityWuhanPeople’s Republic of China Department of Physical Geography and Ecosystem Science Lund UniversityLundSweden School of Computer science and Engineering Nanyang Technological UniversitySingaporeSingapore

Similarity measurement has been a prevailing research topic geographic information science.Geometric similarity measurement inin scaling transformation(GSM_ST)is critical to ensure spatial data quality while balancing detailed information with distinctive features.However,GSM_ST is an uncertain problem due to subjective spatial cognition,global and local concerns,and geometric complexity.Traditional rule-based methods considering multiple consistent conditions require subjective adjustments to characteristics and weights,leading to poor robustness in addressing GSM_ST.This study proposes an unsupervised representation learning framework for automated GSM_ST,using a Graph Autoencoder Network(GAE)and drainage networks as an example.The framework involves constructing a drainage graph,designing the GAE architecture for GSM_ST,and using Cosine similarity to measure similarity based on the GAE-derived drainage embeddings in different scales.We perform extensive experiments and compare methods across 71 drainage networks duringfive scaling transformations.The results show that the proposed GAE method outperforms other methods with a satisfaction ratio of around 88%and has strong robustness.Moreover,our proposed method also can be applied to other scenarios,such as measuring similarity between geographical entities at different times and data from different datasets.

关键词： Geometric similarity measurement drainage network scaling transformation graph autoencoder network

Worldwide impacts of atmospheric vapor pressure deficit on the interannual variability of terrestrial carbon sinks

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National science Review 2022年第4期9卷 33-40页

作者： Bin He Chen Chen Shangrong Lin Wenping Yuan Hans W.Chen Deliang Chen Yafeng Zhang Lanlan Guo Xiang Zhao Xuebang Liu Shilong Piao Ziqian Zhong Rui Wang Rui Tang State Key Laboratory of Earth Surface Processes and Resource Ecology College of Global Change and Earth System ScienceBeijing Normal University department of Application Research Twenty First Century Aerospace Technology Co.Ltd. School of Atmospheric sciences Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai)Sun Yat-sen University Department of Physical Geography and Ecosystem Science Lund University Regional Climate Group Department of Earth SciencesUniversity of Gothenburg Academy of Disaster Reduction and Emergency Management School of GeographyBeijing Normal University State Key Laboratory of Remote Sensing science Faculty of Geographical ScienceBeijing Normal University Sino-French Institute for Earth System science College of Urban and Environmental SciencesPeking University

Interannual variability of the terrestrial ecosystem carbon sink is substantially regulated by various environmental variables and highly dominates the interannual variation of atmospheric carbon dioxide(CO2) concentrations.Thus,it is necessary to determine dominating factors affecting the interannual variability of the carbon sink to improve our capability of predicting future terrestrial carbon sinks.Using global datasets derived from machine-learning methods and process-based ecosystem models,this study reveals that the inter annual variability of the atmospheric vapor pressure deficit(VPD) was significantly negatively correlated with net ecosystem production(NEP) and substantially impacted the inter annual variability of the atmospheric CO2growth rate(CGR).Further analyses found widespread constraints of VPD interannual variability on terrestrial gross primary production(GPP),causing VPD to impact NEP and CGR.Partial correlation analysis confirms the persistent and widespread impacts of VPD on terrestrial carbon sinks compared to other environmental variables.Current Earth system models underestimate the interannual variability in VPD and its impacts on GPP and NEP.Our results highlight the importance of VPD for terrestrial carbon sinks in assessing ecosystems’ responses to future climate conditions.

关键词： vapor pressure deficit net ecosystem production gross vegetation production carbon dioxide concentration

SDI planning using the system dynamics technique within a community of practice:lessons learnt from Tanzania

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Geo-Spatial Information science 2015年第2期18卷 97-110页

作者： Ali MANSOURIAN Alex LUBIDA Petter PILESJÖ Ehsan ABDOLMAJIDI Monica LASSI GIS Center Department of Physical Geography and Ecosystem ScienceLund UniversitySölvegatan 1222362 LundSweden department of Research and Study Services Lund University LibraryLund UniversityHelgonabacken 1Box 3SE-22100 LundSweden

There exist major challenges in accelerating the spatial data infrastructure(SDI)planning process in the developing countries as well as advocating for politicians to support the development of SDI,due to the high complexity of SDI,lack of knowledge and experience,and limited insight in the benefits.To address these challenges,a methodology for SDI planning in Tanzania,based on the system dynamics technique and the communities of practice concept,was adopted and applied within a community consisting of experts from stakeholder organizations.The groups gathered to develop an SDI plan,while they shared their knowledge and discussed their ideas that helped their understanding of SDI.By running the system dynamics model,the development of SDI over time could be simulated that gave the planning community an insight about the future effects of today’s plans and decisions.Finally,an optimum model could be developed by refinements and improvements done with the consensus of the SDI stakeholders.This model included the components and policies that are essential for a successful SDI implementation in Tanzania and can be used as a basis for SDI planning and help to gain political support.Lessons learnt from this research were promising regarding the usability of the methodology for SDI planning in comparable countries.

关键词： spatial data infrastructure(SDI) planning system dynamics technique community of practice

Real-time visualization of 3D city models at street-level based on visual saliency

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science China Earth sciences 2015年第3期58卷 448-461页

作者： MAO Bo BAN YiFang Lars HARRIE Jiangsu Provincial Key Laboratory of E-Business Nanjing University of Finance and Economics College of Computer science and Engineering Nanjing University of Science and Technology department of Urban Planning and Environment KTH Royal Institute of TechnologySE-10044 StockholmSweden Department of Physical Geography and Ecosystem Science Lund UniversityBox118SE-223 62 LundSweden

Street-level visualization is an important application of 3D city models.Challenges to street-level visualization include the cluttering of buildings due to fine detail and visualization performance.In this paper,a novel method is proposed for streetlevel visualization based on visual saliency evaluation.The basic idea of the method is to preserve these salient buildings in a scene while removing those that are non-salient.The method can be divided into pre-processing procedures and real-time visualization.The first step in pre-processing is to convert 3D building models at higher Levels of Detail(Lo Ds) into LoD 1 models with simplified ground plans.Then,a number of index viewpoints are created along the streets; these indices refer to both the position and the direction of each street site.A visual saliency value is computed for each building,with respect to the index site,based on a visual difference between the original model and the generalized model.We calculate and evaluate three methods for visual saliency:local difference,global difference and minimum projection area.The real-time visualization process begins by mapping the observer to its closest indices.The street view is then generated based on the building information stored in those indexes.A user study shows that the local visual saliency method performs better than do the global visual saliency,area and image-based methods and that the framework proposed in this paper may improve the performance of 3D visualization.

关键词：三维城市模型实时可视化视觉街道 3D可视化投影面积建筑信息建筑物

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Sahara’s surface transformation forced an abrupt hydroclimate decline and Neolithic culture transition in northern China

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The Innovation 2024年第1期5卷 70-79页

作者： Yandong Hou Hao Long Sumiko Tsukamoto Zhengyao Lu Jie Chen Daniel EIbarra Toru Tamura Qiong Zhang Weiyi Sun Jingran Zhang Lei Gao Manfred Frechen Ji Shen State Key Laboratory of Lake science and Environment Nanjing Institute of Geography and LimnologyChinese Academy of Sciences(NIGLAS)Nanjing 210008China Leibniz Institute for Applied Geophysics(LIAG) Department of Geochronology30655 HannoverGermany Department of Physical Geography and Ecosystem Science Lund University22100 LundSweden Key Laboratory of Western China’s Environmental Systems(Ministry of Education) College of Earth and Environmental SciencesLanzhou UniversityLanzhou 730000China College of Atmospheric sciences Lanzhou UniversityLanzhou 730000China Institute at Brown for Environment and Society and department of Earth Environmentaland Planetary SciencesBrown UniversityProvidenceRI 02912USA Geological Survey of Japan National Institute of Advanced Industrial Science and TechnologyTsukubaIbaraki 305-8567Japan Graduate School of Frontier sciences University of TokyoKashiwaChiba 277-8561Japan department of physical geography and Bolin Centre for Climate Research Stockholm University10691 StockholmSweden School of geography Nanjing Normal UniversityJiangsu Centre for Collaborative Innovation in Geographical Information Resource Development and ApplicationKey Laboratory of Virtual Geographic EnvironmentMinistry of Education of ChinaNanjing 210023China School of geography and Ocean science Nanjing UniversityNanjing 210023China

The remote forcing from land surface changes in the Sahara is hypothesized to play a pivotal role in modulating the intensity of the East Asian summer monsoon(EASM)through ocean-atmospheric teleconnections.This modulation has far-reaching consequences,particularly in facilitating societal shifts documented in northern China.Here,we present a well-dated lake-level record from the Daihai Lake Basin in northern China,providing quantitative assessments of Holocene monsoonal precipitation and the consequent migrations of the northern boundary of the EASM.Our reconstruction,informed by a water-and-energy balance model,indicates that annual precipitation reached700 mm during 8–5 ka,followed by a rapid decline to tween 5 and 4 ka.This shift coherently aligns with a signi550 mm be-ficant300 km northwestward movement of the EASM northern boundary during the Middle Holocene(MH),in contrast to its current position.Our findings underscore that these changes cannot be entirely attributed to orbital forcing,as corroborated by simulation tests.Climate model simulations deployed in our study suggest that the presence of the Green Sahara during the MH significantly strengthened the EASM and led to a northward shift of the monsoon rainfall belt.Conversely,the Sahara’s reversion to a desert landscape in the late Holocene was accompanied by a corresponding southward retraction of monsoon influence.These dramatic hydroclimate changes during5–4 ka likely triggered or at least contributed to a shift in Neolithic cultures and societal transformation in northern China.With decreasing agricultural productivity,communities transitioned from millet farming to a mixed rainfed agriculture and animal husbandry system.Thus,our findings elucidate not only the variability of the EASM but also the profound implications of a remote forcing,such as surface transformations of the Sahara,on climatic changes and cultural evolution in northern China.

关键词： Holocene monsoon abrupt