Based on the relationship among the geographic events, spatial changes and the database operations, a new automatic (semi-automatic) incremental updating approach of spatio-temporal database (STDB) named as (event-bas...Based on the relationship among the geographic events, spatial changes and the database operations, a new automatic (semi-automatic) incremental updating approach of spatio-temporal database (STDB) named as (event-based) incremental updating (E-BIU) is proposed in this paper. At first, the relationship among the events, spatial changes and the database operations is analyzed, then a total architecture of E-BIU implementation is designed, which includes an event queue, three managers and two sets of rules, each component is presented in detail. The process of the E-BIU of master STDB is described successively. An example of building’s incremental updating is given to illustrate this approach at the end. The result shows that E-BIU is an efficient automatic updating approach for master STDB.展开更多
We report a new horizontal Global Positioning System velocity field in the Chinese mainland from the data analysis of about 2000 GPS sites observed in 2009,2011 and 2013 through three campaigns of the CMONOC project. ...We report a new horizontal Global Positioning System velocity field in the Chinese mainland from the data analysis of about 2000 GPS sites observed in 2009,2011 and 2013 through three campaigns of the CMONOC project. Assuming the crustal block to characterize their kinematic behaviors,we estimate parameters of 22 crustal blocks to fit the GPS-derived velocity by using GIPSY software. We restrict us to compare two competing models in which the rigid blocks and the deforming blocks are involved. Our modeling suggests that the most crustal blocks characterized by coherent movement and internal strain may be better in describing the kinematics of crustal deformation in the Chinese mainland.展开更多
On August 8,2017,an M_(W)6.5 earthquake occurred in Jiuzhaigou County,Sichuan Province,China,on the eastern margin of the Qinghai-Tibet Plateau.This study investigates the coseismic deformation field and fault model w...On August 8,2017,an M_(W)6.5 earthquake occurred in Jiuzhaigou County,Sichuan Province,China,on the eastern margin of the Qinghai-Tibet Plateau.This study investigates the coseismic deformation field and fault model with ascending and descending Sentinel-1 synthetic aperture radar(SAR)images,aftershock distribution,and elastic half-space dislocation model.The regional fault slip pattern is then quantita-tively examined using the boundary element method.The results show that the ascending and descending interferometric synthetic aperture radar(InSAR)coseismic deformation fields display an overall NNW-SSE trend,with more significant deformation on the southwest side of the fault.The coseismic fault geometry is divided into NW and SE sub-faults with strikes of 162.1°and 149.3°,respectively.The coseismic fault slip is dominated by a left-lateral strike-slip movement with an average rake of-2.31°,mainly occurring at a depth of 0-13.04 km with a shape of an approximately inverted triangle.The fault slip features two peak slip zones,with a maximum of 1.39 m.The total seismic moment is 6.34×10^(18) N·m(M_(W)6.47).The boundary element calculation quantitatively indicates that the regional fault slip pattern may be mainly attributable to the changing strike and dip.The strike changes from NNWeSSE to nearly NS direction,and the dip gradually decreases from the Jiuzhaigou earthquake fault in the north to the Huya fault in the south.With these characteristics,the Huya and the Jiuzhaigou earthquake faults form the eastern boundary of the Minshan uplift zone and accommodate the accumulated deformation.展开更多
With the rapid development of social economy and urban−rural integration,the phenomenon of farmland aban-donment worldwide has proved to be one of the main trends of land use and land cover change(LUCC),and profoundly...With the rapid development of social economy and urban−rural integration,the phenomenon of farmland aban-donment worldwide has proved to be one of the main trends of land use and land cover change(LUCC),and profoundly affected the rural landscape and regional ecological environment.Restricted by the natural environ-ment,economic development and backward agricultural technology,the phenomenon of farmland abandonment is also common in the Qingzang Plateau(QP).Therefore,this paper adopted the spatial autocorrelation method to analyze the spatial pattern of abandonment in the agricultural and pastoral areas of the Qingzang Plateau(APA−QP)in 2017,and the geographically weighted regression(GWR)model to explore the effects of geograph-ical resources,socio-economic development and location conditions on farmland abandonment.This study found that:1)From 2015 to 2017,the abandoned farmland area in the APA−QP was approximately 18.23×10^(4)ha,with an overall abandonment rate of 15.18%.On the whole,it showed the distribution characteristics of“strong in the south and weak in the north,strong in the east and weak in the west”.2)There were positive spatial correlation between both abandoned area and abandonment rate in the APA−QP,showing“concave”and“convex”patterns,respectively,mainly concentrated in the Huang−shui Valley and the Southeast Tibet;while in the western and northern regions,the degree of abandonment was relatively low.3)Farmland abandonment in the APA−QP was mainly driven by the geographical environment changes and farmers’decision−making on farmland utilization.There was significant spatial heterogeneity on farmland abandonment associated with the impact of geographical resources,socio−economics and location conditions.The geographical resource factors had a positive impact on the abandonment,and were strongly constrained by natural geographic conditions such as altitude and slope.The farmland resources in the Qingzang Plateau are limited,but are of strategic significance for the sustainable development of agriculture in the whole Qingzang Plateau.In order to realize the rational distribution of agricul-ture and animal husbandry and the sustainable utilization of farmland resources in the plateau region,land use strategies should be implemented according to regional differences and regional advantages in order to ensure the ecological environment security of Qingzang Plateau.展开更多
Invasive exotic species pose a growing threat to the economy,public health,and ecological integrity of nations worldwide. Explaining and predicting the spatial distribution of invasive exotic species is of great impor...Invasive exotic species pose a growing threat to the economy,public health,and ecological integrity of nations worldwide. Explaining and predicting the spatial distribution of invasive exotic species is of great importance to prevention and early warning efforts. We are investigating the potential distribution of invasive exotic species,the environmental factors that influence these distributions,and the ability to predict them using statistical and information-theoretic approaches. For some species,detailed presence/absence occurrence data are available,allowing the use of a variety of standard statistical techniques. However,for most species,absence data are not available. Presented with the challenge of developing a model based on presence-only information,we developed an improved logistic regres-sion approach using Information Theory and Frequency Statistics to produce a relative suitability map. This paper generated a variety of distributions of ragweed(Ambrosia artemisiifolia L.) from logistic regression models applied to herbarium specimen location data and a suite of GIS layers including climatic,topographic,and land cover information. Our logistic regression model was based on Akaike's Information Criterion(AIC) from a suite of ecologically reasonable predictor variables. Based on the results we provided a new Frequency Statistical method to compartmentalize habitat-suitability in the native range. Finally,we used the model and the compartmentalized criterion developed in native ranges to “project” a potential distribution onto the exotic ranges to build habitat-suitability maps.展开更多
Nowadays Surveying and Mapping(S&M)production and services are facing some serious challenges such as real-timization of data acquisition,automation of information processing,and intellectualization of service app...Nowadays Surveying and Mapping(S&M)production and services are facing some serious challenges such as real-timization of data acquisition,automation of information processing,and intellectualization of service applications.The main reason is that current digitalized S&M technologies,which involve complex algorithms and models as the core,are incapable of completely describing and representing the diverse,multi-dimensional and dynamic real world,as well as addressing high-dimensional and nonlinear spatial problems using simple algorithms and models.In order to address these challenges,it is necessary to explore the use of natural intelligence in S&M,and to develop intelligentized S&M technologies,which are knowledge-guided and algorithm-based.This paper first discusses the basic concepts and ideas of intelligentized S&M,and then analyzes and defines its fundamental issues in the analysis and modeling of natural intelligence in S&M,the construction and realization of hybrid intelligent computing paradigm,and the mechanism and path of empowering production.Further research directions are then proposed in the four areas,including knowledge systems,technologies and methodologies,application systems,and instruments and equipments of intelligentized S&M.Finally,some institutional issues related to promoting scientific research and engineering applications in this area are discussed.展开更多
The construction of thematic map symbols is a very complex and intellectually demanding process,but thematic symbols can be automatically generated and easily shared on the web using the syntactic structure of semanti...The construction of thematic map symbols is a very complex and intellectually demanding process,but thematic symbols can be automatically generated and easily shared on the web using the syntactic structure of semantic symbols.In this paper,the symbol types,inner structure,and design pattern are discussed.A syntactic construction theory based on letter (thematic maps primitive)-word (single thematic symbol)-sentence (combined symbols or complex symbols) structure model is proposed to automate the construction of thematic map symbols.As a result of this research,symbols can be defined using cartographic primitives which are arranged according to syntactic principles.A semiotic model and word-centered construction theory can be integrated into interactive cartography as represented by the technology of Internet.Finally,the concepts and schema of this theory are discussed,and some examples are presented based a web thematic cartographic system to verify its utility.展开更多
In this paper the application of spatialization technology on metadata quality check and updating was dis-cussed. A new method based on spatialization was proposed for checking and updating metadata to overcome the de...In this paper the application of spatialization technology on metadata quality check and updating was dis-cussed. A new method based on spatialization was proposed for checking and updating metadata to overcome the defi-ciency of text based methods with the powerful functions of spatial query and analysis provided by GIS software. Thismethod employs the technology of spatialization to transform metadata into a coordinate space and the functions ofspatial analysis in GIS to check and update spatial metadata in a visual environment. The basic principle and technicalflow of this method were explained in detail, and an example of implementation using ArcMap of GIS software wasillustrated with a metadata set of digital raster maps. The result shows the new method with the support of interactionof graph and text is much more intuitive and convenient than the ordinary text based method, and can fully utilize thefunctions of GIS spatial query and analysis with more accuracy and efficiency.展开更多
A relational matching approach for imagery-to-GIS data is presented. This method applies image aspect interpretation and geospatial data mining techniques to realize their integration. Three-dimensional (3D) primitive...A relational matching approach for imagery-to-GIS data is presented. This method applies image aspect interpretation and geospatial data mining techniques to realize their integration. Three-dimensional (3D) primitives, standing for houses, are chosen and their projections are represented by these aspects. The hierarchy aspect graphs are constructed to represent their interconnected relations. In this connection arcs are described by attribute data via formulated coding regulations. The nodes of the graph represent image features and their attributes can contain measurements on these features. The arcs of the graph represent relations between features and their attributes can contain measurements on spatial relations. Data mining is used to discover the semantic relationship of these primitives. Aerial images are interpreted via these aspects and geospatial data mining. Our experimental results demonstrate that the method presented is capable of effectively interpreting aerial images and extracting high accuracy from the DBM (digital building model) at a rate of 87%.展开更多
Precision agriculture, and more specifically Site-Specific Crop Management(SSCM), has been implemented in some form across nearly all agricultural production systems over the past 25 years. Adoption has been greatest ...Precision agriculture, and more specifically Site-Specific Crop Management(SSCM), has been implemented in some form across nearly all agricultural production systems over the past 25 years. Adoption has been greatest in developed agricultural countries. In this review article, the current situation of SSCM adoption and application is investigated from the perspective of a developed(UK) and developing(China) agricultural economy. The current state-of-the art is reviewed with an emphasis on developments in position system technology and satellite-based remote sensing. This is augmented with observations on the differences between the use of SSCM technologies and methodologies in the UK and China and discussion of the opportunities for(and limitations to)increasing SSCM adoption in developing agricultural economies. A particular emphasis is given to the role of socio-demographic factors and the application of responsible research and innovation(RRI) in translating agritechnologies into China and other developing agricultural economies. Several key research and development areas are identified that need to be addressed to facilitate the delivery of SSCM as a holistic service into areas with low precision agriculture(PA) adoption. This has implications for developed as well as developing agricultural economies.展开更多
Inter-city mobility is one of the most important issues in the UN Sustainable Development Goals,as it is essential to access the regional labour market,goods and services,and to constrain the spread of infectious dise...Inter-city mobility is one of the most important issues in the UN Sustainable Development Goals,as it is essential to access the regional labour market,goods and services,and to constrain the spread of infectious diseases.Although the gravity model has been proved to be an effective model to describe mobility among settlements,knowledge is still insufficient in regions where dozens of megacities interact closely and over 100 million people reside.In addition,the existing knowledge is limited to overall population mobility,while the difference in inter-city travel with different purposes is unexplored on such a large geographic scale.We revisited the gravity laws of inter-city mobility using the 2.12 billion trip chains recorded by 40.48 million mobile phone users’trajectories in the Jing-Jin-Ji Region,which contains China’s capital Beijing.Firstly,unlike previous studies,we found that non-commuting rather than commuting is the dominant type of inter-city mobility(89.3%).Noncommuting travellers have a travel distance 42.3%longer than commuting travellers.Secondly,we developed more accurate gravity models for the spatial distribution of inter-city commuting and non-commuting travel.We also found that inter-city mobility has a hierarchical structure,as the distribution of inter-city travel volume follows Zipf’s law.In particular,the hierarchy of non-commuting travel volume among the cities is more in line with an ideal Zipf distribution than commuting travel.Our findings contribute to new knowledge on basic inter-city mobility laws,and they have significant applications for regional policies on human mobility.展开更多
Land water, one of the important components of land cover, is the indispensable and important basic information for climate change studies, ecological environment assessment, macro-control analysis, etc. This article ...Land water, one of the important components of land cover, is the indispensable and important basic information for climate change studies, ecological environment assessment, macro-control analysis, etc. This article describes the overall study on land water in the program of global land cover remote sensing mapping. Through collection and processing of Landsat TM/ETM+, China's HJ-1 satellite image, etc., the program achieves an effective overlay of global multi-spectral image of 30 m resolution for two base years, namely, 2000 and 2010, with the image rectification accuracy meeting the requirements of 1:200000 mapping and the error in registration of images for the two periods being controlled within 1 pixel. The indexes were designed and selected reasonably based on spectral features and geometric shapes of water on the scale of 30 m resolution, the water information was extracted in an elaborate way by combining a simple and easy operation through pixel-based classification method with a comprehensive utilization of various rules and knowledge through the object-oriented classification method, and finally the classification results were further optimized and improved by the human-computer interaction, thus realizing high-resolution remote sensing mapping of global water. The completed global land water data results, including Global Land 30-water 2000 and Global Land 30-water 2010, are the classification results featuring the highest resolution on a global scale, and the overall accuracy of self-assessment is 96%. These data are the important basic data for developing relevant studies, such as analyzing spatial distribution pattern of global land water, revealing regional difference, studying space-time fluctuation law, and diagnosing health of ecological environment.展开更多
Land surface water(LSW) is one of the most important resources for human survival and development, and it is also a main component of global water recycling. A full understanding of the spatial distribution of land su...Land surface water(LSW) is one of the most important resources for human survival and development, and it is also a main component of global water recycling. A full understanding of the spatial distribution of land surface water and a continuous measuring of its dynamics can support to diagnose the global ecosystem and environment. Based on the Global Land 30-water 2000 and Global Land 30-water 2010 products, this research analyzed the spatial distribution pattern and temporal fluctuation of land surface water under scale-levels of global, latitude and longitude, continents, and climate zones. The Global Land 30-water products were corrected the temporal inconsistency of original remotely sensed data using MODIS time-series data, and then calculated the indices such as water area, water ration and coefficient of spatial variation for further analysis. Results show that total water area of land surface is about 3.68 million km2(2010), and occupies 2.73% of land area. The spatial distribution of land surface water is extremely uneven and is gathered mainly in mid- to high-latitude area of the Northern Hemisphere and tropic area. The comparison of water ratio between 2000 and 2010 indicates the overall fluctuation is small but spatially differentiated. The Global Land 30-water products and the statistics provided the fundamental information for analyzing the spatial distribution pattern and temporal fluctuation of land surface water and diagnosing the global ecosystem and environment.展开更多
Assuring the quality of land-cover data is one of the major challenges for large- area mapping projects. Although the use of geospatial knowledge and ancillary data in improving land-cover classification has been stud...Assuring the quality of land-cover data is one of the major challenges for large- area mapping projects. Although the use of geospatial knowledge and ancillary data in improving land-cover classification has been studied since the early 1980 s, mature methods and efficient supporting tools are still lacking. This paper presents a geospatial knowledge-based verification and improvement approach for global land cover(GLC) mapping at 30-m resolution. A set of verification rules is derived from three types of land cover and its change knowledge(natural, cultural and temporal constraints). A group of web-based supporting tools is developed to facilitate the integration of and access to large amounts of ancillary data and to support online data manipulation and analysis as well as collaborative verification workflows. With this approach, two 30-m GLC datasets(Globe Land-2000 and Globe Land-2010) were verified and modified. The results indicate that the data quality of Globe Land30 has been largely improved.展开更多
For partial linear model Y = Xτβ0 + g0(T) + with unknown β0 ∈ Rd and an unknown smooth function g0, this paper considers the Huber-Dutter estimators of β0, scale σ for the errors and the function g0 approximated...For partial linear model Y = Xτβ0 + g0(T) + with unknown β0 ∈ Rd and an unknown smooth function g0, this paper considers the Huber-Dutter estimators of β0, scale σ for the errors and the function g0 approximated by the smoothing B-spline functions, respectively. Under some regularity conditions, the Huber-Dutter estimators of β0 and σ are shown to be asymptotically normal with the rate of convergence n-1/2 and the B-spline Huber-Dutter estimator of g0 achieves the optimal rate of convergence in nonparametric regression. A simulation study and two examples demonstrate that the Huber-Dutter estimator of β0 is competitive with its M-estimator without scale parameter and the ordinary least square estimator.展开更多
Listed by UNESCO in 1987 as a World Heritage site,the world-famous Ming Great Wall stretches several thousands of kilometers across northern China,and served as a massive military defensive system which in recent time...Listed by UNESCO in 1987 as a World Heritage site,the world-famous Ming Great Wall stretches several thousands of kilometers across northern China,and served as a massive military defensive system which in recent times has a unique historical,artistic and scientific value.Due to historical reasons and lack of advanced technologies,construction resources and conservation status of Ming Great Wall have not been investigated in any systematic manner;indeed,the extent of the Great Wall has not even been measured.This has resulted in a shortage of reliable first-hand scientific information on actual size,spatially resource distribution and preservation status of this World Heritage site.Driven by the urgent need to establish protection,research,renovation and management of Ming Great Wall,a comprehensive investigation and spatial mapping was jointly organized and completed by the State Bureau of Survey and Mapping and State Administration of Culture Heritage.High resolution digital stereo models at 1:10000 map scale covering the whole length of the Ming Great Wall have been created by photogrammetric reconstruction using nearly ten thousand aerial images.Spatial distribution and attributes of the wall sections,trenches and various subsidiary facilities in the surroundings of the Great Wall were measured with the help of digital photogrammetry workstations and results from field studies.Reliable and precise information about the Ming Great Wall has now been obtained and documented,including surface lengths,resource distribution,and preservation status.For example,the total length of Ming Great Wall is 8851.8 km,of which 6259.6 km is of actual wall,2232.5 km of natural terrain,and 359.7 km of trenches.In category lengths,1828.8 km is constructed of stone,3411.3 km of earth,249.6 km in brick,197.5 km of cliff wall and the rest 572.4 km of other means.Such information provides the scientific basis and strong platform in helping to delineate areas needing protection,in planning conservation and renovation programs,as well as digital archiving for posterity and web-based applications for modern promotions of one of the world's great attractions,the Ming Great Wall.展开更多
The tropospheric delay is a significant error source in Global Navigation Satellite System(GNSS)positioning and navigation.It is usually projected into zenith direction by using a mapping function.It is particularly i...The tropospheric delay is a significant error source in Global Navigation Satellite System(GNSS)positioning and navigation.It is usually projected into zenith direction by using a mapping function.It is particularly important to establish a model that can provide stable and accurate Zenith Tropospheric Delay(ZTD).Because of the regional accuracy difference and poor stability of the traditional ZTD models,this paper proposed two methods to refine the Hopfield and Saastamoinen ZTD models.One is by adding annual and semi-annual periodic terms and the other is based on Back-Propagation Artificial Neutral Network(BP-ANN).Using 5-year data from 2011 to 2015 collected at 67 GNSS reference stations in China and its surrounding regions,the four refined models were constructed.The tropospheric products at these GNSS stations were derived from the site-wise Vienna Mapping Function 1(VMP1).The spatial analysis,temporal analysis,and residual distribution analysis for all the six models were conducted using the data from 2016 to 2017.The results show that the refined models can effectively improve the accuracy compared with the traditional models.For the Hopfield model,the improvement for the Root Mean Square Error(RMSE)and bias reached 24.5/49.7 and 34.0/52.8 mm,respectively.These values became 8.8/26.7 and 14.7/28.8 mm when the Saastamoinen model was refined using the two methods.This exploration is conducive to GNSS navigation and positioning and GNSS meteorology by providing more accurate tropospheric prior information.展开更多
Artificial surfaces, characterized with intensive land-use changes and complex landscape structures, are important indicators of human impacts on terrestrial ecosystems. Without high-resolution land-cover data at cont...Artificial surfaces, characterized with intensive land-use changes and complex landscape structures, are important indicators of human impacts on terrestrial ecosystems. Without high-resolution land-cover data at continental scale, it is hard to evaluate the impacts of urbanization on regional climate, ecosystem processes and global environment. This study constructed a hierarchical classification system for artificial surfaces, promoted a remote sensing method to retrieve subpixel components of artificial surfaces from 30-m resolution satellite imageries(Globe Land30) and developed a series of data products of high-precision urban built-up areas including impervious surface and vegetation cover in Asia in 2010. Our assessment, based on multisource data and expert knowledge, showed that the overall accuracy of classification was 90.79%. The mean relative error for the impervious surface components of cities was 0.87. The local error of the extracted information was closely related to the heterogeneity of urban buildings and vegetation in different climate zones. According to our results, the urban built-up area was 18.18×104 km2, accounting for 0.59% of the total land surface areas in Asia; urban impervious surfaces were 11.65×104 km2, accounting for 64.09% of the total urban built-up area in Asia. Vegetation and bare soils accounted for 34.56% of the urban built-up areas. There were three gradients: a concentrated distribution, a scattered distribution and an indeterminate distribution from east to west in terms of spatial pattern of urban impervious surfaces. China, India and Japan ranked as the top three countries with the largest impervious surface areas, which respectively accounted for 32.77%, 16.10% and 11.93% of the urban impervious surface area of Asia. We found the proportions of impervious surface and vegetation cover within urban built-up areas were closely related to the economic development degree of the country and regional climate environment. Built-up areas in developed countries had relatively low impervious surface and high public green vegetation cover, with 50–60% urban impervious surfaces in Japan, South Korea and Singapore. In comparison, the proportion of urban impervious surfaces in developing countries is approaching or exceeding 80% in Asia. In general, the composition and spatial patterns of built-up areas reflected population aggregation and economic development level as well as their impacts on the health of the environment in the sub-watershed.展开更多
Information regarding Land cover and change (LCC) over time is essential for a variety of Societal Benefits Areas(SBA), such as environmental change analysis, geographical condition monitoring, urban and rural managem...Information regarding Land cover and change (LCC) over time is essential for a variety of Societal Benefits Areas(SBA), such as environmental change analysis, geographical condition monitoring, urban and rural management, earth surface process modeling, and sustainable development.Since the middle of 1990s, the international scientific communities have devoted tremendous efforts to Global Land Cover (GLC) mapping, and developed a number of coarser resolution (ranging from 300-m to 1 km) data products.展开更多
文摘Based on the relationship among the geographic events, spatial changes and the database operations, a new automatic (semi-automatic) incremental updating approach of spatio-temporal database (STDB) named as (event-based) incremental updating (E-BIU) is proposed in this paper. At first, the relationship among the events, spatial changes and the database operations is analyzed, then a total architecture of E-BIU implementation is designed, which includes an event queue, three managers and two sets of rules, each component is presented in detail. The process of the E-BIU of master STDB is described successively. An example of building’s incremental updating is given to illustrate this approach at the end. The result shows that E-BIU is an efficient automatic updating approach for master STDB.
基金supported partially by the National Natural Science Foundation of China （Nos.40774009 and 40974016） the National Hi-tech R＆D Program of China （No. 2009AA121402）+1 种基金 the Special Project Fund of Taishan Scholars of Shandong Province China （No. TSXZ0502） the Research ＆ Innovation Team Support Program of SDUST China
基金supported by the CMONOC project,National Natural Science Foundation of China(41204001,41274036,and 41274037)State 863 Projects(2013AA122501)the Surveying and Mapping Basic Research Fund of Earth Space Environment and Geodetic Measurement Laboratory in Wuhan University(130104)
文摘We report a new horizontal Global Positioning System velocity field in the Chinese mainland from the data analysis of about 2000 GPS sites observed in 2009,2011 and 2013 through three campaigns of the CMONOC project. Assuming the crustal block to characterize their kinematic behaviors,we estimate parameters of 22 crustal blocks to fit the GPS-derived velocity by using GIPSY software. We restrict us to compare two competing models in which the rigid blocks and the deforming blocks are involved. Our modeling suggests that the most crustal blocks characterized by coherent movement and internal strain may be better in describing the kinematics of crustal deformation in the Chinese mainland.
基金This work was supported by the National Key Research and Development Program of China(2018YFC1503603,2016YFB0501405)the National Natural Science Foundation of China(41874011,41774011)。
文摘On August 8,2017,an M_(W)6.5 earthquake occurred in Jiuzhaigou County,Sichuan Province,China,on the eastern margin of the Qinghai-Tibet Plateau.This study investigates the coseismic deformation field and fault model with ascending and descending Sentinel-1 synthetic aperture radar(SAR)images,aftershock distribution,and elastic half-space dislocation model.The regional fault slip pattern is then quantita-tively examined using the boundary element method.The results show that the ascending and descending interferometric synthetic aperture radar(InSAR)coseismic deformation fields display an overall NNW-SSE trend,with more significant deformation on the southwest side of the fault.The coseismic fault geometry is divided into NW and SE sub-faults with strikes of 162.1°and 149.3°,respectively.The coseismic fault slip is dominated by a left-lateral strike-slip movement with an average rake of-2.31°,mainly occurring at a depth of 0-13.04 km with a shape of an approximately inverted triangle.The fault slip features two peak slip zones,with a maximum of 1.39 m.The total seismic moment is 6.34×10^(18) N·m(M_(W)6.47).The boundary element calculation quantitatively indicates that the regional fault slip pattern may be mainly attributable to the changing strike and dip.The strike changes from NNWeSSE to nearly NS direction,and the dip gradually decreases from the Jiuzhaigou earthquake fault in the north to the Huya fault in the south.With these characteristics,the Huya and the Jiuzhaigou earthquake faults form the eastern boundary of the Minshan uplift zone and accommodate the accumulated deformation.
基金This research was supported by the National Social Science Fund of China(Grant No.20&ZD090)the Second Tibetan Plateau Scientific Expedition and Research Program(Grant No.2019QZKK0405)the Na-tional Natural Science Foundation of China(Grant No.42071249,Grant No.42001199).
文摘With the rapid development of social economy and urban−rural integration,the phenomenon of farmland aban-donment worldwide has proved to be one of the main trends of land use and land cover change(LUCC),and profoundly affected the rural landscape and regional ecological environment.Restricted by the natural environ-ment,economic development and backward agricultural technology,the phenomenon of farmland abandonment is also common in the Qingzang Plateau(QP).Therefore,this paper adopted the spatial autocorrelation method to analyze the spatial pattern of abandonment in the agricultural and pastoral areas of the Qingzang Plateau(APA−QP)in 2017,and the geographically weighted regression(GWR)model to explore the effects of geograph-ical resources,socio-economic development and location conditions on farmland abandonment.This study found that:1)From 2015 to 2017,the abandoned farmland area in the APA−QP was approximately 18.23×10^(4)ha,with an overall abandonment rate of 15.18%.On the whole,it showed the distribution characteristics of“strong in the south and weak in the north,strong in the east and weak in the west”.2)There were positive spatial correlation between both abandoned area and abandonment rate in the APA−QP,showing“concave”and“convex”patterns,respectively,mainly concentrated in the Huang−shui Valley and the Southeast Tibet;while in the western and northern regions,the degree of abandonment was relatively low.3)Farmland abandonment in the APA−QP was mainly driven by the geographical environment changes and farmers’decision−making on farmland utilization.There was significant spatial heterogeneity on farmland abandonment associated with the impact of geographical resources,socio−economics and location conditions.The geographical resource factors had a positive impact on the abandonment,and were strongly constrained by natural geographic conditions such as altitude and slope.The farmland resources in the Qingzang Plateau are limited,but are of strategic significance for the sustainable development of agriculture in the whole Qingzang Plateau.In order to realize the rational distribution of agricul-ture and animal husbandry and the sustainable utilization of farmland resources in the plateau region,land use strategies should be implemented according to regional differences and regional advantages in order to ensure the ecological environment security of Qingzang Plateau.
基金Supported by the National Natural Science Foundation of China (Grant No. 40371084)U.S. Geological Survey (Grant No. 03CRCN0001)UW-Madison funded under U.S. Geological Survey cooperative agreement (Grant No. 03CRAG0016)
文摘Invasive exotic species pose a growing threat to the economy,public health,and ecological integrity of nations worldwide. Explaining and predicting the spatial distribution of invasive exotic species is of great importance to prevention and early warning efforts. We are investigating the potential distribution of invasive exotic species,the environmental factors that influence these distributions,and the ability to predict them using statistical and information-theoretic approaches. For some species,detailed presence/absence occurrence data are available,allowing the use of a variety of standard statistical techniques. However,for most species,absence data are not available. Presented with the challenge of developing a model based on presence-only information,we developed an improved logistic regres-sion approach using Information Theory and Frequency Statistics to produce a relative suitability map. This paper generated a variety of distributions of ragweed(Ambrosia artemisiifolia L.) from logistic regression models applied to herbarium specimen location data and a suite of GIS layers including climatic,topographic,and land cover information. Our logistic regression model was based on Akaike's Information Criterion(AIC) from a suite of ecologically reasonable predictor variables. Based on the results we provided a new Frequency Statistical method to compartmentalize habitat-suitability in the native range. Finally,we used the model and the compartmentalized criterion developed in native ranges to “project” a potential distribution onto the exotic ranges to build habitat-suitability maps.
基金The Key Program of the National Natural Science Foundation of China(No.41930650)The Strategic Consulting Project of Chinese Academy of Engineering(No.2019-ZD-16)。
文摘Nowadays Surveying and Mapping(S&M)production and services are facing some serious challenges such as real-timization of data acquisition,automation of information processing,and intellectualization of service applications.The main reason is that current digitalized S&M technologies,which involve complex algorithms and models as the core,are incapable of completely describing and representing the diverse,multi-dimensional and dynamic real world,as well as addressing high-dimensional and nonlinear spatial problems using simple algorithms and models.In order to address these challenges,it is necessary to explore the use of natural intelligence in S&M,and to develop intelligentized S&M technologies,which are knowledge-guided and algorithm-based.This paper first discusses the basic concepts and ideas of intelligentized S&M,and then analyzes and defines its fundamental issues in the analysis and modeling of natural intelligence in S&M,the construction and realization of hybrid intelligent computing paradigm,and the mechanism and path of empowering production.Further research directions are then proposed in the four areas,including knowledge systems,technologies and methodologies,application systems,and instruments and equipments of intelligentized S&M.Finally,some institutional issues related to promoting scientific research and engineering applications in this area are discussed.
文摘The construction of thematic map symbols is a very complex and intellectually demanding process,but thematic symbols can be automatically generated and easily shared on the web using the syntactic structure of semantic symbols.In this paper,the symbol types,inner structure,and design pattern are discussed.A syntactic construction theory based on letter (thematic maps primitive)-word (single thematic symbol)-sentence (combined symbols or complex symbols) structure model is proposed to automate the construction of thematic map symbols.As a result of this research,symbols can be defined using cartographic primitives which are arranged according to syntactic principles.A semiotic model and word-centered construction theory can be integrated into interactive cartography as represented by the technology of Internet.Finally,the concepts and schema of this theory are discussed,and some examples are presented based a web thematic cartographic system to verify its utility.
基金Project 40301042 supported by Natural Science Foundation of China
文摘In this paper the application of spatialization technology on metadata quality check and updating was dis-cussed. A new method based on spatialization was proposed for checking and updating metadata to overcome the defi-ciency of text based methods with the powerful functions of spatial query and analysis provided by GIS software. Thismethod employs the technology of spatialization to transform metadata into a coordinate space and the functions ofspatial analysis in GIS to check and update spatial metadata in a visual environment. The basic principle and technicalflow of this method were explained in detail, and an example of implementation using ArcMap of GIS software wasillustrated with a metadata set of digital raster maps. The result shows the new method with the support of interactionof graph and text is much more intuitive and convenient than the ordinary text based method, and can fully utilize thefunctions of GIS spatial query and analysis with more accuracy and efficiency.
基金Projects 40574008 supported by the National Natural Science Foundation of China0131893 by the US National Science Foundation
文摘A relational matching approach for imagery-to-GIS data is presented. This method applies image aspect interpretation and geospatial data mining techniques to realize their integration. Three-dimensional (3D) primitives, standing for houses, are chosen and their projections are represented by these aspects. The hierarchy aspect graphs are constructed to represent their interconnected relations. In this connection arcs are described by attribute data via formulated coding regulations. The nodes of the graph represent image features and their attributes can contain measurements on these features. The arcs of the graph represent relations between features and their attributes can contain measurements on spatial relations. Data mining is used to discover the semantic relationship of these primitives. Aerial images are interpreted via these aspects and geospatial data mining. Our experimental results demonstrate that the method presented is capable of effectively interpreting aerial images and extracting high accuracy from the DBM (digital building model) at a rate of 87%.
基金supported by the STFC Newton Agri-Tech program through three projects: (1) Exemplar Smart Farming in Newcastle, (2) Exploring the Potential for Precision Nutrient Management in China, and (3) PAFiC: Precision Agriculture for Family-farms in China (ref.: ST/N006801/1)
文摘Precision agriculture, and more specifically Site-Specific Crop Management(SSCM), has been implemented in some form across nearly all agricultural production systems over the past 25 years. Adoption has been greatest in developed agricultural countries. In this review article, the current situation of SSCM adoption and application is investigated from the perspective of a developed(UK) and developing(China) agricultural economy. The current state-of-the art is reviewed with an emphasis on developments in position system technology and satellite-based remote sensing. This is augmented with observations on the differences between the use of SSCM technologies and methodologies in the UK and China and discussion of the opportunities for(and limitations to)increasing SSCM adoption in developing agricultural economies. A particular emphasis is given to the role of socio-demographic factors and the application of responsible research and innovation(RRI) in translating agritechnologies into China and other developing agricultural economies. Several key research and development areas are identified that need to be addressed to facilitate the delivery of SSCM as a holistic service into areas with low precision agriculture(PA) adoption. This has implications for developed as well as developing agricultural economies.
基金supported by the National Natural Science Foundation of China(Grant Nos.41925003&42130402)the Beijing Municipal Social Science Foundation(Grant No.20JCB073)。
文摘Inter-city mobility is one of the most important issues in the UN Sustainable Development Goals,as it is essential to access the regional labour market,goods and services,and to constrain the spread of infectious diseases.Although the gravity model has been proved to be an effective model to describe mobility among settlements,knowledge is still insufficient in regions where dozens of megacities interact closely and over 100 million people reside.In addition,the existing knowledge is limited to overall population mobility,while the difference in inter-city travel with different purposes is unexplored on such a large geographic scale.We revisited the gravity laws of inter-city mobility using the 2.12 billion trip chains recorded by 40.48 million mobile phone users’trajectories in the Jing-Jin-Ji Region,which contains China’s capital Beijing.Firstly,unlike previous studies,we found that non-commuting rather than commuting is the dominant type of inter-city mobility(89.3%).Noncommuting travellers have a travel distance 42.3%longer than commuting travellers.Secondly,we developed more accurate gravity models for the spatial distribution of inter-city commuting and non-commuting travel.We also found that inter-city mobility has a hierarchical structure,as the distribution of inter-city travel volume follows Zipf’s law.In particular,the hierarchy of non-commuting travel volume among the cities is more in line with an ideal Zipf distribution than commuting travel.Our findings contribute to new knowledge on basic inter-city mobility laws,and they have significant applications for regional policies on human mobility.
基金supported by the National High-Tech R&D Program of China(Grant Nos.2009AA122003 and 2009AA122001)
文摘Land water, one of the important components of land cover, is the indispensable and important basic information for climate change studies, ecological environment assessment, macro-control analysis, etc. This article describes the overall study on land water in the program of global land cover remote sensing mapping. Through collection and processing of Landsat TM/ETM+, China's HJ-1 satellite image, etc., the program achieves an effective overlay of global multi-spectral image of 30 m resolution for two base years, namely, 2000 and 2010, with the image rectification accuracy meeting the requirements of 1:200000 mapping and the error in registration of images for the two periods being controlled within 1 pixel. The indexes were designed and selected reasonably based on spectral features and geometric shapes of water on the scale of 30 m resolution, the water information was extracted in an elaborate way by combining a simple and easy operation through pixel-based classification method with a comprehensive utilization of various rules and knowledge through the object-oriented classification method, and finally the classification results were further optimized and improved by the human-computer interaction, thus realizing high-resolution remote sensing mapping of global water. The completed global land water data results, including Global Land 30-water 2000 and Global Land 30-water 2010, are the classification results featuring the highest resolution on a global scale, and the overall accuracy of self-assessment is 96%. These data are the important basic data for developing relevant studies, such as analyzing spatial distribution pattern of global land water, revealing regional difference, studying space-time fluctuation law, and diagnosing health of ecological environment.
基金supported by the National High-Tech Research Program of China(Grant Nos.2009AA122001 and 2009AA122004)
文摘Land surface water(LSW) is one of the most important resources for human survival and development, and it is also a main component of global water recycling. A full understanding of the spatial distribution of land surface water and a continuous measuring of its dynamics can support to diagnose the global ecosystem and environment. Based on the Global Land 30-water 2000 and Global Land 30-water 2010 products, this research analyzed the spatial distribution pattern and temporal fluctuation of land surface water under scale-levels of global, latitude and longitude, continents, and climate zones. The Global Land 30-water products were corrected the temporal inconsistency of original remotely sensed data using MODIS time-series data, and then calculated the indices such as water area, water ration and coefficient of spatial variation for further analysis. Results show that total water area of land surface is about 3.68 million km2(2010), and occupies 2.73% of land area. The spatial distribution of land surface water is extremely uneven and is gathered mainly in mid- to high-latitude area of the Northern Hemisphere and tropic area. The comparison of water ratio between 2000 and 2010 indicates the overall fluctuation is small but spatially differentiated. The Global Land 30-water products and the statistics provided the fundamental information for analyzing the spatial distribution pattern and temporal fluctuation of land surface water and diagnosing the global ecosystem and environment.
基金funded by the National Natural Science Foundation of China (Grant No. 41231172)the Special Fund for Surveying, Mapping and Geoinformation Scientific Research in the Public Welfare (Grant No. 201512028)National High-Tech R&D Program of China (Grant No. 2013AA122802)
文摘Assuring the quality of land-cover data is one of the major challenges for large- area mapping projects. Although the use of geospatial knowledge and ancillary data in improving land-cover classification has been studied since the early 1980 s, mature methods and efficient supporting tools are still lacking. This paper presents a geospatial knowledge-based verification and improvement approach for global land cover(GLC) mapping at 30-m resolution. A set of verification rules is derived from three types of land cover and its change knowledge(natural, cultural and temporal constraints). A group of web-based supporting tools is developed to facilitate the integration of and access to large amounts of ancillary data and to support online data manipulation and analysis as well as collaborative verification workflows. With this approach, two 30-m GLC datasets(Globe Land-2000 and Globe Land-2010) were verified and modified. The results indicate that the data quality of Globe Land30 has been largely improved.
基金the National Natural Science Foundation of China (Grant Nos. 10671106, 10771017)
文摘For partial linear model Y = Xτβ0 + g0(T) + with unknown β0 ∈ Rd and an unknown smooth function g0, this paper considers the Huber-Dutter estimators of β0, scale σ for the errors and the function g0 approximated by the smoothing B-spline functions, respectively. Under some regularity conditions, the Huber-Dutter estimators of β0 and σ are shown to be asymptotically normal with the rate of convergence n-1/2 and the B-spline Huber-Dutter estimator of g0 achieves the optimal rate of convergence in nonparametric regression. A simulation study and two examples demonstrate that the Huber-Dutter estimator of β0 is competitive with its M-estimator without scale parameter and the ordinary least square estimator.
文摘Listed by UNESCO in 1987 as a World Heritage site,the world-famous Ming Great Wall stretches several thousands of kilometers across northern China,and served as a massive military defensive system which in recent times has a unique historical,artistic and scientific value.Due to historical reasons and lack of advanced technologies,construction resources and conservation status of Ming Great Wall have not been investigated in any systematic manner;indeed,the extent of the Great Wall has not even been measured.This has resulted in a shortage of reliable first-hand scientific information on actual size,spatially resource distribution and preservation status of this World Heritage site.Driven by the urgent need to establish protection,research,renovation and management of Ming Great Wall,a comprehensive investigation and spatial mapping was jointly organized and completed by the State Bureau of Survey and Mapping and State Administration of Culture Heritage.High resolution digital stereo models at 1:10000 map scale covering the whole length of the Ming Great Wall have been created by photogrammetric reconstruction using nearly ten thousand aerial images.Spatial distribution and attributes of the wall sections,trenches and various subsidiary facilities in the surroundings of the Great Wall were measured with the help of digital photogrammetry workstations and results from field studies.Reliable and precise information about the Ming Great Wall has now been obtained and documented,including surface lengths,resource distribution,and preservation status.For example,the total length of Ming Great Wall is 8851.8 km,of which 6259.6 km is of actual wall,2232.5 km of natural terrain,and 359.7 km of trenches.In category lengths,1828.8 km is constructed of stone,3411.3 km of earth,249.6 km in brick,197.5 km of cliff wall and the rest 572.4 km of other means.Such information provides the scientific basis and strong platform in helping to delineate areas needing protection,in planning conservation and renovation programs,as well as digital archiving for posterity and web-based applications for modern promotions of one of the world's great attractions,the Ming Great Wall.
基金the Fundamental Research Funds for the Central Universities(No.2021XJDC01)the State Key Laboratory of Resources and Environmental Information System,the Key Laboratory of Geospace Environment and Geodesy,Ministry of Education,Wuhan University(No.19-02-08)+1 种基金the Guangxi Key Laboratory of Spatial Information and Geomatics(No.19-050-11-01)the National Natural Science Foundation of China(Nos.41804038,42001368).
文摘The tropospheric delay is a significant error source in Global Navigation Satellite System(GNSS)positioning and navigation.It is usually projected into zenith direction by using a mapping function.It is particularly important to establish a model that can provide stable and accurate Zenith Tropospheric Delay(ZTD).Because of the regional accuracy difference and poor stability of the traditional ZTD models,this paper proposed two methods to refine the Hopfield and Saastamoinen ZTD models.One is by adding annual and semi-annual periodic terms and the other is based on Back-Propagation Artificial Neutral Network(BP-ANN).Using 5-year data from 2011 to 2015 collected at 67 GNSS reference stations in China and its surrounding regions,the four refined models were constructed.The tropospheric products at these GNSS stations were derived from the site-wise Vienna Mapping Function 1(VMP1).The spatial analysis,temporal analysis,and residual distribution analysis for all the six models were conducted using the data from 2016 to 2017.The results show that the refined models can effectively improve the accuracy compared with the traditional models.For the Hopfield model,the improvement for the Root Mean Square Error(RMSE)and bias reached 24.5/49.7 and 34.0/52.8 mm,respectively.These values became 8.8/26.7 and 14.7/28.8 mm when the Saastamoinen model was refined using the two methods.This exploration is conducive to GNSS navigation and positioning and GNSS meteorology by providing more accurate tropospheric prior information.
基金financially supported by the National Natural Science Foundation of China (Grant Nos. 41371408 & 41371409)the National High Technology Research and Development Program of China (Grant No. 2013AA122802)the State Key Development Program for Basic Research of China (Grant No. 413714082014CB954302)
文摘Artificial surfaces, characterized with intensive land-use changes and complex landscape structures, are important indicators of human impacts on terrestrial ecosystems. Without high-resolution land-cover data at continental scale, it is hard to evaluate the impacts of urbanization on regional climate, ecosystem processes and global environment. This study constructed a hierarchical classification system for artificial surfaces, promoted a remote sensing method to retrieve subpixel components of artificial surfaces from 30-m resolution satellite imageries(Globe Land30) and developed a series of data products of high-precision urban built-up areas including impervious surface and vegetation cover in Asia in 2010. Our assessment, based on multisource data and expert knowledge, showed that the overall accuracy of classification was 90.79%. The mean relative error for the impervious surface components of cities was 0.87. The local error of the extracted information was closely related to the heterogeneity of urban buildings and vegetation in different climate zones. According to our results, the urban built-up area was 18.18×104 km2, accounting for 0.59% of the total land surface areas in Asia; urban impervious surfaces were 11.65×104 km2, accounting for 64.09% of the total urban built-up area in Asia. Vegetation and bare soils accounted for 34.56% of the urban built-up areas. There were three gradients: a concentrated distribution, a scattered distribution and an indeterminate distribution from east to west in terms of spatial pattern of urban impervious surfaces. China, India and Japan ranked as the top three countries with the largest impervious surface areas, which respectively accounted for 32.77%, 16.10% and 11.93% of the urban impervious surface area of Asia. We found the proportions of impervious surface and vegetation cover within urban built-up areas were closely related to the economic development degree of the country and regional climate environment. Built-up areas in developed countries had relatively low impervious surface and high public green vegetation cover, with 50–60% urban impervious surfaces in Japan, South Korea and Singapore. In comparison, the proportion of urban impervious surfaces in developing countries is approaching or exceeding 80% in Asia. In general, the composition and spatial patterns of built-up areas reflected population aggregation and economic development level as well as their impacts on the health of the environment in the sub-watershed.
文摘Information regarding Land cover and change (LCC) over time is essential for a variety of Societal Benefits Areas(SBA), such as environmental change analysis, geographical condition monitoring, urban and rural management, earth surface process modeling, and sustainable development.Since the middle of 1990s, the international scientific communities have devoted tremendous efforts to Global Land Cover (GLC) mapping, and developed a number of coarser resolution (ranging from 300-m to 1 km) data products.
