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Incorporation of intra-city human mobility into urban growth simulation:A case study in Beijing

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Journal of Geographical Sciences 2022年第5期32卷 892-912页

作者： WANG Siying FEI Teng LI Weifeng ZHANG Anqi GUO Huagui du yunyan School of Resource and Environmental Science Wuhan UniversityWuhan430079China Department of Urban Planning and Design The University of Hong KongHong KongChina Guangdong-Hong Kong-Macao Joint Laboratory for Smart Cities Hong KongChina Institute of Geographic Sciences and Natural Resources Research CASBeijing100101China School of Architecture and Urban-rural Planning Fuzhou UniversityFuzhou350108China

The effective modeling of urban growth is crucial for urban planning and analyzing the causes of land-use *** urbanization has slowed down in most megacities,improved urban growth modeling with minor changes has become a crucial open issue for these *** existing models are based on stationary factors and spatial proximity,which are unlikely to depict spatial connectivity between *** research attempts to leverage the power of real-world human mobility and consider intra-city spatial interaction as an imperative driver in the context of urban growth ***,the gravity model,which considers both the scale and distance effects of geographical locations within cities,is employed to characterize the connection between land areas using individual trajectory data from a macro *** then becomes possible to integrate human mobility factors into a neural-network-based cellular automata(ANN-CA)for urban growth modeling in Beijing from 2013 to *** results indicate that the proposed model outperforms traditional models in terms of the overall accuracy with a 0.60%improvement in Cohen’s Kappa coefficient and a 0.41%improvement in the figure of *** addition,the improvements are even more significant in districts with strong relationships with the central area of *** example,we find that the Kappa coefficients in three districts(Chaoyang,Daxing,and Shunyi)are considerably higher by more than 2.00%,suggesting the possible existence of a positive link between intense human interaction and urban *** paper provides valuable insights into how fine-grained human mobility data can be integrated into urban growth simulation,helping us to better understand the human-land relationship.

关键词： cellular automata urban growth simulation human mobility massive trajectories

Human’s digital footprints on the Qinghai-Tibet Plateau:Variations during festivals and impacts on nature reserves

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Journal of Geographical Sciences 2021年第2期31卷 179-194页

作者： du yunyan TU Wenna LIANG Fuyuan YI Jiawei State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources ResearchCASBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China Department of Earth Atmosphericand Geographic Information SciencesWestern Illinois UniversityMacombIL61455USA

Mobile internet and wireless communication technologies have produced unprecedented location-aware *** big geospatial data can be used as a proxy measure of the‘digital footprints’left by us on the planet and provide a valuable opportunity to understand the dynamic and short-term human disturbance on the nature at fine *** study investigated the spatiotemporal variations of human’s digital footprints on the Qinghai-Tibet Plateau using smartphone-users-generated Tencent’s location request *** results showed that human’s digital footprints cover less than 5%of Qinghai and Tibet,exhibiting either a U-shaped or an N-shaped temporal change pattern during the major *** changes of the digital footprints manifested a transition process from dispersion to concentration in Xining and *** disturbance assessment of seven large nature reserves on the plateau showed that the Qinghai Lake is the most disturbed one as shown by 14.6%of its area is stained with human digital footprints and the areal average of footprint intensity is 1.59,and the disturbance was significantly escalated during the National Day *** contrast,the Qangtang and Hoh Xil are the least affected nature reserves with the two indices less than 1%and 0.1,respectively.

关键词： digital footprint space-time variations human impact nature reserve location request

Tracking the evolution processes and behaviors of mesoscale eddies in the South China Sea：a global nearest neighbor filter approach

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Acta Oceanologica Sinica 2017年第11期36卷 27-37页

作者： YI Jiawei du yunyan WANG Dongxiao ZHOU Chenghu State Key Laboratory of Resources and Environmental Information System Institute of Geographic Science and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China University of Chinese Academy of Sciences Beijing 100049 China State Key Laboratory of Tropical Oceanography (LTO) South China Sea Institute of Oceanology Chinese Academy of Sciences Guangzhou 510301 China

The eddy tracking approach is developed using the global nearest neighbor filter（GNNF） to investigate the evolution processes and behaviors of mesoscale eddies in the South China Sea（SCS）. Combining the Kalman filter and optimal data association technologies, the GNNF algorithm is able to reduce pairing errors to 0.2% in tracking synthetic eddy tracks, outperforming other existing methods. A total of 4 913 eddy tracks that last more than a week are obtained by the GNNF during 1993–2012. The analysis of a growth and a decay based on 3 445 simple eddy tracks show that eddy radius, amplitude, and vorticity smoothly increase during the first half of lifetime and decline during the second half following a parabola opening downwards. The genesis of eddies mainly clusters northwest and southwest of Luzon Island whereas the dissipations concentrate the Xisha Islands where the underwater bay traps and terminates eddies. West of the Luzon Strait, northwest of Luzon Island, and southeast of Vietnam are regions where eddy splits and mergers are frequently observed. Short disappearances mainly distribute in the first two regions. Moreover, eddy splits generally result in a decrease of the radius and the amplitude whereas eddy mergers induce growing up. Eddy intensity and vorticity, on the contrary, are strengthened in the eddy splits and diminished in mergers.

关键词： mesoscale ocean eddies eddy tracking eddy split eddy merger South China Sea

Multifractal filtering method for extraction of ocean eddies from remotely sensed imagery

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Acta Oceanologica Sinica 2006年第5期25卷 27-38页

作者： GE Yong du yunyan CHENG Qiuming LI Ce State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences ＆ Natural Re-sources Research Chinese Academy of Sciences Beijing 100101 China Department of Earth and Space Science and Engineering York University Toronto M3J 1P3 Canada State Key Laboratory of Geo-Processes and Mineral Resources China University of Geosciences Beijing 100083 China

Traditional methods of extracting the ocean wave eddy information from remotely sensed imagery mainly use the edge detection technology such as Canny and Hough operators. However, due to the complexities of ocean eddies and image itself, it is sometimes difficult to successfully detect ocean eddies using these methods. A mnltifractal filtering technology is proposed for extraction of ocean eddies and demonstrated using NASA MODIS, SeaWiFS and NOAA satellite data set in the typical area, such as ocean west boundary current. Results showed that the new method has a superior performance over the traditional methods.

关键词： remotely sensed imagery extraction of ocean eddies multifractal filtering

A quantitative morphometric comparison of cockpit and doline karst landforms

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Journal of Geographical Sciences 2014年第6期24卷 1069-1082页

作者： LIANG Fuyuan du yunyan GE Yong LI Ce Department of Geography Western Illinois University Macomb IL 61455 USA State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources Research CAS Beijing 100101 China The Institute of Remote Sensing and Digital Earth CAS Beijing 100094 China

This study presented a quantitative comparison of cockpit and doline karst by examining the numbers and characteristics of typical types of landform entities that are developed in Guilin（Guangxi, China）, La Alianza（PR, USA）, Avalton（KY, USA）, and Oolitic（IN, USA）. Five types of landform entities were defined： isolated hill（IH）, clustered hills（CHs）, isolated sinkhole（IS）, clustered sinkholes（CSs）, and clustered hills with sinkholes（CHSs）. An algorithm was developed to automatically identify these types of landform entities by examining the contour lines on topographic maps of two cockpit karst areas（Guilin and La Alianza） and two doline karst areas（Oolitic and Avalton）. Within each specific study area, the CHSs is the least developed type yet with a larger size and higher relief. The IH and IS entities are smaller in size, lower in relief, and outnumber their clustered counterparts. The total numbers of these types of entities are quite different in cockpit and doline karst areas. Doline karst is characterized by more negative（IS and CSs） than positive（IH and IHs） landforms and vice versa for cockpit karst. For example, the Guilin study area has 1192 positive landform entities in total, which occupy 9.81% of the total study area. It has only 622 negative landform entities occupying only 3.91% of the total study area. By contrast, the doline karst in Oolitic has 130 negative while only 10 positive landform entities. The positive and negative landforms in Oolitic occupy 12.68% and 2.61% of the total study area, respectively. Furthermore, average relief and slope of the landform entities are much higher and steeper in the cockpit karst than the doline karst areas. For instance, the average slope of CHs in Alvaton is 3.90 degrees while it is 19.78 degrees in La Alianza. The average relief of CSs is 4.07 m and 34.29 m in Oolitic and Guilin respectively. Such a difference within a specific area or between the cockpit and doline karst may reveal different controls on the d

关键词： cockpit doline contours morphometric characteristics topographic map karst

Analysis of ecological quality in Lhasa Metropolitan Area during 1990-2017 based on remote sensing and Google Earth Engine platform

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Journal of Geographical Sciences 2021年第2期31卷 265-280页

作者： HUANG Huiping CHEN Wei ZHANG Yuan QIAO Lin du yunyan Aerospace Information Research Institute CASBeijing 100094China University of Chinese Academy of Sciences Beijing 100049China State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources ResearchCASBeijing 100101China

Based on a total of 519 images,the composite images with the lowest possible cloud cover were generated at pixel level with image synthesis method on Google Earth Engine(GEE)*** Remote Sensing Ecological Index(RSEI)was adopted,and calculated in an efficient way with the assistance of parallel cloud computing of the GEE *** RSEI was used in this paper to evaluate and monitor the eco-environmental quality of the Lhasa Metropolitan *** show that:(1)The ecological quality is better in the west than in the east of Lhasa Metropolitan Area,with Lhasa as an approximate dividing *** ecological quality improved and then deteriorated dramatically before 2000,with the mean RSEI value dropping from 0.51 to 0.46;the trend was followed by a gradual increase up until 2017,with the mean RSEI value increased from 0.46 to 0.55.(2)The RSEI is weakly and positively correlated with socioeconomic *** indicates that the population growth and economic development did not negatively influence the ecological quality,but actually boosted it.(3)The GEE can serve as an efficient computing platform for the assessment and monitoring of eco-environmental quality in vast regions.

关键词： Lhasa Metropolitan Area ecological quality remote sensing ecological index Google Earth Engine

A model of sea surface temperature front detection based on a threshold interval

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Acta Oceanologica Sinica 2014年第7期33卷 65-71页

作者： PING Bo SU Fenzhen MENG Yunshan FANG Shenghui du yunyan School of Remote Sensing and Information Engineering Wuhan University Laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Collaborative Innovation Center of South China Sea Studies

A model （Bayesian oceanic front detection, BOFD） of sea surface temperature （SST） front detection in satel- lite-derived SST images based on a threshold interval is presented, to be used in different applications such as climatic and environmental studies or fisheries. The model first computes the SST gradient by using a Sobel algorithm template. On the basis of the gradient value, the threshold interval is determined by a gradi- ent cumulative histogram. According to this threshold interval, front candidates can be acquired and prior probability and likelihood can be calculated. Whether or not the candidates are front points can be deter- mined by using the Bayesian decision theory. The model is evaluated on the Advanced Very High-Resolution Radiometer images of part of the Kuroshio front region. Results are compared with those obtained by using several SST front detection methods proposed in the literature. This comparison shows that the BOFD not only suppresses noise and small-scale fronts, but also retains continuous fronts.

关键词： sea surface temperature threshold setting Sobel algorithm edge detection front detection

Spatial information recognizing of ocean eddies based on virtual force field and its application

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Acta Oceanologica Sinica 2007年第4期26卷 44-52页

作者： LI Ce du yunyan SU Fenzhen YANG Xiaomei XU Jun State Key Laboratory of Resources and Environment Information System Institute of Geographic Science and Natural Resources Chinese Academy of Sciences Beijing 100101 China

A new approach to detecting ocean eddies automatically from remote sensing imageries based on the ocean eddy＇s eigen-pattern in remote sensing imagery and ＂force field-based shape extracting method＂ is proposed. First, the analysis on extracting eddies＇ edges from remote sensing imagery using conventional edge detection arithmetic operators is performed and returns digitized vector edge data as a result. Second, attraction forces and fusion forces between edge curves were analyzed and calculated based on the vector eddy edges. Thirdly, the virtual significant spatial patterns of eddy were detected automatically using iterative repetition followed by optimized rule. Finally, the spatial form auto-detection of different types of ocean eddies was done using satellite images. The study verified that this is an effective way to identify and detect the ocean eddy with a complex form.

关键词： ocean eddy spatial pattern recognizing force field detection

Integration technology research on marine geographical information system

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Acta Oceanologica Sinica 2008年第6期27卷 40-48页

作者： XUE Cunjin SU Fenzhen du yunyan YANG Xiaomei State Key Laboratory of Resource and Environment Information System Institute of Geographical Science ＂and Natural Re-sources Chinese Academy of Sciences Beijing 100101 China Center for Earth Observation and Digital Earth Chinese Academy of Science Beijing 100191 China Graduate School Chinese Academy of Sciences Beijing 100039 China

It is urgent and necessary to integrate a marine geographical information system （MGIS） with marine remote sensing detection modules. On the basis of the current technology and features of applications, an open three-layer integration framework is designed. At the data layer, a two-level three-base integration mechanism based on the plug-in technology is applied; At the function layer, an integration mode based on API, DLL, EXE and COM is discussed; and at the application layer, a sharing mechanism based on the clients/service is adopted. As an example, the remote sensing integrated application information system of China＇s coastal zone and offshore （MaXplorer1. 0） with muhiecology remote sensing fusion and assimilation module, surge detection module as well as eight other thematic application modules is integrated, and the key technology of integration is discussed at different layers and in different modules. The result shows that it is possible to realize the conformity of technology and resources and to provide the incorporate technology platform for marine information operational functioning after applying the integration framework.

关键词： marine geographical information system ( MGIS) marine remote sensing application modules ( MRSAMs) systemintegration integration modes