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  • 2010 Volume 12 Issue 2
    Published: 25 April 2010
      
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  • ARTICLES
    On the Fragile Eco-environmental Information Tupu of Coastal Zone in Fujian Province
    CHEN Jing
    2010, 12(2): 159-166.
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    Coastal Zone is the transfer of land and sea areas.With economic development and opening to the outside world,various exploiting activities on coastal zone,on the one hand,promote economic development of coastal areas;on the other hand,make coastal areas facing increasing pressures,such as population increase,consumption of resources and serious environmental pollution,etc.In addition,coastal zone suffers frequent natural disasters,such as typhoon,drought and earthquake.Accordingly,coastal ecological environment shows a typical characteristic of vulnerability.In this paper,fragile ecological environment in the coastal zone was studied based on the Geo-Information Tupu methodology.Firstly,it constructs spatiotemporal database through earth observation,field investigation and social economic statistics,and a symptom Tupu is constructed from data mining and knowledge discovery.Then a diagnose Tupu is extracted by combined evaluation and spatiotemporal analysis.Finally,implement Tupu is generated by the support of forecasting model and the decision project is formed.The practice proves that the study of the fragile properties for eco-environment by the method of Geo-Informatics graphic analysis is almost same as the reality of Fujian Province.The fragile eco-environment including present situation,driving factors and the future trend could be reflected more intuitively through information Tupu.The study of fragile eco-environmental information Tupu by means of Tupu inversion and simulating the spatiotemporal change of eco-environment of coast zone would supply important scientific basis for the planning policy decision of sustainable development in coast zone as well as the countermeasure making of environmental management and disaster prevention and reduction through comprehensive assessment and forecasting of fragile eco-environment in coastal zone by Tupu form.
  • ARTICLES
    Modeling Method and Its Application of Virtual Trees in Consideration of the Spatial Features
    WANG Zhangang, ZHUANG Dafang
    2010, 12(2): 167-173.
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    Three-dimensional modeling of trees is one of the key issues of building virtual forest environment.On the basis of analyses the morphology of trees,an object-oriented vector-raster mixed tree model is proposed.The main components of the trees were seen as vector model and the leaves as raster model in the tree model.The main components of the trees have been abstracted into several classes based on object-oriented thinking.Each vector class is composed of basic vector point,arc,face and body.The model has the obvious level feature.Five topological relations are introduced in detail among trunk,segment,branch and leaf.The three-dimensional modeling method of trees which combines the advantages of both L-systems and three-dimensional geometry framework is proposed base on rules and restriction.In the modeling method branching laws and spatial distribution characteristics of leaves are changed into rules.The tree model is consistent with the biophysical characteristics of trees.And it is provided with space geometrical features and topological relations.Model parameters are controlled by threshold,model adjusting and random restriction.The model achieved a higher precision.Tree restriction involves tree configuration,leaf size,leaf area index and random.Finally the tree model and modeling method are realized by Visual C++and OpenGL.The modeling method is tested by measurement data.The obtained tree model is more in line with the actual morphological structure parameters and bio-physical indicators than any other model.The obtained tree model supports physiological and ecological process simulation,rule discovering,and parameter calculation.
  • ARTICLES
    Application of Toponymy to the Historical LUCC Researches in Northeast China——Taking Zhenlai County of Jilin Province as An Example
    LV Yan, ZHANG Shuwen, YANG Jiuchun
    2010, 12(2): 174-179.
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    Researches on historical land use and land cover change(LUCC) have important significance for the future human activities.In this paper,taking Zhenlai County of Jilin Province as the study area,the application of toponymy and other correlative historical data to acquire the beginning period of large-scale land reclamation in Northeast China was discussed.And integrating with reclassification methods,centroid transfer analysis and overlay analysis,the characteristics of residential area evolvement and land development in Zhenlai County were analyzed according to the historical records in the toponymy and so on.It was documented that during the Kangxi Period in Qing Dynasty or 1853,there were small-scale of land reclamation along with the settlement activities in Zhenlai County.From about 1875 on,the land reclamation became continuous,while it was almost in a natural state before.In the early days,with lagging techniques,the evolution of villages and land development process were interactional.Therefore,from the view of village evolution,we could deduce it was the most prominent period for land reclamation during 1907-1912;and by 1975,the village pattern in Zhenlai County was formed and stable,at the same time the land reclamation activities has transformed from individual behavior into the collective and mechanized farming.In brief,under the influences of various policies in Northeast China and natural disasters and wars,land development in Zhenlai County expanded from the eastern and central flat regions to the western high-lying areas.
  • ARTICLES
    Different Methods for Prediction of Spatial Patterns of Paddy Soil Organic Carbon Density in Changxing County,Zhejiang Province
    LIU Sha, REN Hongyan, SHI Xuezheng, PAN Jianjun, WANG Hongjie
    2010, 12(2): 180-185.
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    Soil organic carbon (SOC) plays an important role in conserving soil fertility,improving soil quality,and changing global climate.SOC is closely related to the spatial distribution pattern of soil organic carbon density (SOCD).It is necessary to predict SOCD for the un-sampled points.Thus,it is really meaningful to derive accurately spatially data of SOCD from discrete data using spatial prediction methods for SOC evolution trend research and for the exploration of the role that SOC sequestration played in alleviating global climate change.Based on 87 paddy soil profiles collected from Changxing County,Zhejiang Province for the Second National Soil Survey,this paper attempted to predict the spatial patterns of paddy soil organic carbon density in Changxing County using two different methods.The data of paddy soil profiles were used directly by Universal Kriging (UK),and the data of paddy soil profiles and 1:50 000 digital map of Changxing County were used by pedological professional knowledge-based (PKB) method to predict the spatial patterns of paddy soil organic carbon density in Changxing County.Prediction was evaluated in virtue of mean absolute error (MAE) and root mean square error (RMSE).MAE (24.7) and RMSE (43.1) of PKB method were lower than UK method.The sum squared error (ESS) of the UK method only can explain 20% of the total variation.The PKB method widened the range of SOC density (49.6-650.1 t C hm-2) as compared with the UK method the range of SOC density (66.7-165.7 t C hm-2).The prediction by PKB method had less smoothing effect and more details of depicting the local variation under complex terrain.Therefore,PKB method was a better method for predicting paddy soil organic carbon density in Changxing County in this study.
  • ARTICLES
    GML Spatial Data Index Mechanism Based on Ex-Dewey Prefix Encoding and R-tree
    CHEN Jianhua, WANG Weihong, MIAO Fang
    2010, 12(2): 186-193.
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    Severe challenges are faced by GML spatial data effective query processing while masses of GML spatial data are being produced.While,to query GML spatial data effectively,index is one of the key factors which control the data query performance.Considering XML format encoding style of GML spatial data,in order to take full advantages of Dewey prefix encoding scheme and achieve its new updating strategy that node's inserting and deleting do not effecting others' encoding values,a kind of extended Dewey encoding scheme,Ex-Dewey,was proposed,which is intended to encode the whole GML spatial data documents and construct index to GML non-spatial data.The construction model and processing strategy of non-spatial data index based on Ex-Dewey were well given and discussed.The whole nodes in GML spatial data document firstly are encoded based on Ex-Dewey,and GML non-spatial data index is constructed with three levels,the nodes index can be queried,inserted,modified and deleted while GML non-spatial data were correspondingly operated.Combining with Ex-Dewey,GML spatial data index construction mechanism based on R-tree was proposed,and its construction model and processing strategy were also well given and discussed.The whole GML features in GML spatial data document are the spatial objects.Extracting every GML feature's spatial coordinates and constructing its minimum boundary rectangle(that is MBR),the MBR and its feature's Ex-Dewey encoding value are set as the parameters of R-tree functions.Using R-tree spatial index construction functions with MBR and encoding value,the GML spatial data's index are constructed.Then,all spatial data index's query,insertion,modification and deletion can be operated using R-tree functions with GML feature's MBR and encoding value.Ex-Dewey and R-tree are independent and closely related between GML spatial and non-spatial data index constructions,which integrally implement index mechanism of GML data.Using this index mechanism,GML spatial and non-spatial data can be queried,inserted,modified and deleted effectively and correctly.This index mechanism is hoped to be used on index constructing of native GML spatial database system or GML document sets.
  • ARTICLES
    Heterogeneous Data Searching Based on Geologic Time Ontology
    DONG Shaochun, YIN Hongwei, XU Gang
    2010, 12(2): 194-199.
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    Geologic time is fundamental information for earth science problems.It is commonly described in diverse resources in different styles and formats.Traditional information searching method couldn't extract implicit meaning and relationships from terms in these datasets.Ontology is defined as an explicit formal specification of a shared conceptualization which can play a central role in semantic heterogeneity problem and lead to semantic integration of data across several disciplines of earth sciences.In this paper,we adopt ontology approach to resolve geologic time semantic heterogeneous problems among earth science relational databases.We firstly construct geologic time ontology and then encode it in OWL.This owl provides an organizational structure for classifying geologic time data that can be discovered by both human beings and computers.Based on this ontology,a semantic mapping mechanism for querying among heterogeneous earth science databases is addressed.We describe this mechanism which generates candidate matches from targeted geologic databases and specific ontology manually,and then creates data mapping and translate data based on matches automatically.We apply this mechanism to a four-layer hierarchical system based on WebGIS.A search example is given at the end of the paper.The result shows that this mechanism can discover matches with high accuracy and provide one simple query interface for heterogeneous databases.It resolves both syntactic and semantic heterogeneity and allowing integration of multiple distributed databases.
  • ARTICLES
    Model Metadata Management and Its Application in Knowledge Services Grid Platform
    LIN Jiaxiang, MA Weibin, WU Xiaozhu, CHEN Chongcheng, WANG Weibin
    2010, 12(2): 200-206.
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    A model metadata standard is basically a set of rules on recording model information,more specifically,the rules for recording information about a computer model.While the number of computer models is growing at quite a rate in the network environment,the need for a standardized metadata format for models description is growing with each new model.Only through a standardized format can models be compared and contrasted to find a model fit for a particular application,and only through model metadata can a potential user be able to better decide which model is of the most appropriate.In a word,it is an effective means to share and distribute the knowledge and experience gained in model technology.So,in this paper,we briefly describe the necessity to construct model metadata in information system,and provide a basic framework for grid services model metadata in grid environment.Hence,a two level metadata model is adopted to define and to illuminate model metadata,which is held to consist of an identifier,permission indication,run conditions,model parameters,type information,model details,and references.The first four items are the contents of basic set which are indispensable,and the last four items are the contents of extended set which are optional.The sum of the basic set and the extended set is the global method metadata.Then we explain the principle of model metadata organization and management by using XML as the description language,and the realization of model metadata management module based on B/S architecture,where model metadata is organized and stored in XML file,and it is explored in web browsers.It would be a good way to organize the services discovered in the grid test-bed,and it would also be a step in the direction of producing a unified method of recording models.Finally,through the creation and integration of the model metadata management module into an existing geospatial knowledge services grid platform GeoKS-Grid,we analysis and discuss the application strategy and process of model metadata under the guideline of grid workflow when executing grid services,the effort of which is taking place both in laboratory and industry.
  • ARTICLES
    Definition and Representation of Property Volume of Three Dimensional Cadastre
    ZHANG Lingling, SHI Yunfei, GUO Renzhong, LI Lin
    2010, 12(2): 207-213.
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    Cadastre is a tool which is used to manage national land resources and assets.Traditional cadastre is two-dimensional one which takes parcel as basic management unit to administer land surface right,and its theoretical basis is consistency of the right nationality of the same parcel in the vertical direction,namely the ownership rights of underground,surface and ground space belong to the identical obligee.Due to the backwardness of the past economic development,land use mainly concentrated on the two-dimensional surface and it isn't necessary to extend land use into the third dimension.Therefore,traditional two-dimensional cadastre which takes surface right as core can satisfy social demands well.In recent decades,the rapid increase in population and intensified urbanization make the land use of urban areas,especially business centers under rising pressures.In order to provide more available space,city development extends unceasingly to the third dimension.Three-dimensional land use makes the subject of property become pluralism in the vertical direction,namely underground,surface and ground space can be stratified development and are distributed to different obligees.Tendency of Three-dimensional land use brings forth challenges to traditional land management theories and methods.Three-dimensional cadastre also needs a kind of basic unit like two-dimensional land parcel to register and manage property in three-dimensional space,this kind of three-dimensional basic unit is called property volume in this paper.We will take right entities such as land and property as basis,use right space as reference,research dividing mode of land and property in three-dimensional space,analyze existing form,dividing mode and space form of two kinds of basic unit,generalize theirs basic characteristic.Based on these substantive characteristics,we give the definition and representation of property volume,and test the correctness and validity of the given property volume.
  • ARTICLES
    Study on Integrative Data Production for Digital Urban Management——A Case of Zhengzhou City
    YANG Ruixia, WANG Hanbo, ZHANG Li
    2010, 12(2): 214-219.
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    According to the requirements of data construction for digital urban management,combined with the actualities of the basic geographic data and the urban management data resources and the demand of basic geographic spatial data for the land and planning departments in Zhengzhou,the working principle and process of photogrammetric mapping,urban parts investigation,geo-coding census were analyzed in the process of digital urban management data construction,and the interaction in its process of task was studied.Digital urban management data construction integrative operation procedure was proposed which includes the process design and integrative implementation of the aerial survey of 1∶500 topographic maps,Digital Orthographic Map(DOM) production,urban parts measurement,geo-code survey and integrated database of data etc according to their links,and during the data process of producing,the interacting procedure was considered.This provides the assurance to the completion of large-scale urban geospatial data,urban management topics data collection and database construction in a relatively short period of time,meets the urgent needs of the basic spatial data for the digital urban management,urban cadastral measurement and so on.The research shows that the integrative data construction is a reference application way for the data constructions,which makes full use of the logic of relations and the possibility of sharing among the data.Using this project,the construction projects ministry of digital city management system in Zhengzhou City completed digital urban management data acquisition and digital database construction in a relatively short period of time,the data utilization efficiency was improved.The integrative data construction not only speeds up the process of data construction and expands the construction data contents,but also ensures the quality of the data at the same time.
  • ARTICLES
    Design and Analysis of a Classification Scheme of Geographical Named Entities
    ZHNAG Xueying, ZHANG Chunju, LV Guonian
    2010, 12(2): 220-227.
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    With the increasing applications of natural language in geographical information science,resolution of geospatial information in natural language has become one of the hot issues.Geographical named entities are identifiers of geographical location information in natural language,which include a majority of popular geographical reference systems such as geographical names,addresses,postal codes,telephone numbers and other relative location descriptions.A complete classification scheme of geographical named entities may help implement resolution,storage,management,analysis and sharing of geographical information in natural language.Commonly-used classifications,i.e.classifications of geographical features,classifications of place names,and organization classifications are identified such disadvantages as over specificity of class items,without the consideration of the relationship of time and space,and the ability of representation of partial geographical entities in natural language.To overcome these problems,based on the annotation results of geographical named entities in Chinese documents,we design a classification scheme of geographical named entities(GNEC) with the consideration of their location,attributes,geographical features and temporal features.GNEC includes one main classification of geographical feature types and one subdivision classification of Chinese historical dynasties.Finally,the semantic compatibility between our proposed classification and GB/T 18521-2001,GB/T 13923-2006,Feature Type Classification for Chinese Historical Places of Harvard University and Feature Type Thesaurus of Alexandria Digital Library are analyzed qualitatively and quantitatively.It is noted that a unique geographical entity is usually described with diverse words in natural language,and sometimes it represents different physical location.Classification schemes aim to conceptualize geographical named entities.Undoubtedly,construction of ontologies based on classification schemes could solve this kind of problem(i.e.semantic ambiguity of geographical named entities) effectively.
  • ARTICLES
    Framework of the e-Coastal Science Platform for the Coastal Zone Eco-environment Studies
    HOU Xiyong, LU Qingshui, TANG Cheng, LIU Xin
    2010, 12(2): 228-234.
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    e-Science is about collaborations in areas of scientific research.It will change the way that scientific research is undertaken due to its fundamental goal of minimizing the distance between scientists and information technologies.At the national level,more emphasis are put on researches and constructions of grid and other advanced infrastructure,but scientists individually are more concerned with practical tools and methods that can be integrated on personal computers.The coastal zone is a very special area on the earth where the environmental and ecological processes are very different from that in inland or deep-sea,therefore the coastal zone researches have an especially strong demand for information technology.In past years,great progresses have been made by researchers at home and abroad with regard to information systems and coastal zone management systems.However,the emergence and the fast development of e-Science have not only provided a good opportunity but also pose a very serious challenge for us.It is necessary to develop the e-Science platform in order to meet the increasing needs of distributed and synergetic research activities for the coastal zone environment and ecosystem studies.Therefore,in this paper,the concept of 'e-Coastal Science' was put forward.And the principle,framework,technique route and essential techniques for the e-Coastal Science platform were talked about.In detail,a framework that consist three macro-layers,five technique-units and three research-units was designed for the e-Coastal Science platform.The three macro-layers were IT Infrastructure,GeoScience Platform and Coastal Science Platform respectively.The five technique-units were hardware platform,database platform,simulating platform,synergetic & communicating platform and data information release platform respectively.The three research-units were inshore sea area environment monitoring and simulation,hydrology and ecosystem simulation of coastal river basin,and the integrated coastal zone management respectively.To achieve the e-Coastal Science platform,a detailed and feasible technique roadmap was designed mainly based on Duckling 1.2,ArcGIS 9.3 and professional modeling tools.
  • ARTICLES
    Data Organization and System Architecture of Sino-family-tree GIS
    WEN Yongning, LV Guonian, CHEN Min, SU Hongjun
    2010, 12(2): 235-241.
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    Family tree,official history and chorography jointly build the entire history datum in China.The family tree,also called pedigree,is much informative in society,ethnology,custom,geography,population,economy,people and religion.It is significant to carry the data mining and regularization work on family tree for reconstructing spatial-temporal pedigree,reproducing the civilization skeleton of China and developing the national culture as well as spirit.However,due to the lack of technology,the traditional record and expression pattern can not reflect the movement,rise and fall of the family in spatial and temporal space accurately.So Family Tree GIS conception was proposed and it is combined with GIS as its technology supporting.The spatial relationships underlying family tree are imposed and the reconstruction,integration and recurrence of the family tree is its core study content.In detail,Family tree data model and the spatio-temporal supporting framework are designed according to the characteristics of traditional family tree.And then,some key technologies used in building family-tree GIS are discussed especially such as SOA based on Web Service,XML and XML Schema technology,distributed GIS platform oriented the public and the Web 2.0,also technology of management and drawing mass vector data,technique of generation SVG based on DOT,asynchronous network calling and interaction based on AJAX,XML are discussed.Thirdly,the framework of family tree GIS was proposed and the prototype system was introduced in this paper.Finally,taking a family-tree as a study case,building,analysis and representation of the family-tree is discussed.The experiments have shown that the family tree GIS we proposed is a good approach for the study of conventional family tree,and it will be helpful for future researches on family tree.
  • ARTICLES
    Research of Urban Expansion in Siping City Based On Remote Sensing and GIS
    YIN Fang, FENG Min, ZHONG Feng, LI Xiuxia
    2010, 12(2): 242-247.
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    Urbanization is a major trend in recent years all around the world.China has experienced rapid development since reform and opening-up.Therefore,urban expansion has been significant in this period.Based on the RS and GIS methods,Siping City,a medium city in Jilin Province,is selected as a study case with five remote sensing images in 31 years.After a series of image processing,the five phases of urban boundaries were acquired.It is obvious that the Siping City is partially shaped by river,roads and freeway.Then,the area-perimeter fractal dimensions are adopted to calculate fractal characteristics of urban area based on the box-counting method.After that the compact ratio is calculated to describe the shape characteristic of Siping City.In this paper,the Siping Statistical Yearbook is collected to find out the relationship between economy growth and urban expansion.The process and characteristics of urban expansion are analyzed using urban area change,fractal dimension,compactness and statistical data as well as GIS technology.The results showed that there are four stages in this period.It expended fastest from 1979 to 1991.Between 2001 and 2007,it expended fast as well and emphasized more on urban connotation construction.And this is in agreement with the Siping Statistical Yearbook.Because the urban expansion is influenced by roads,railroads and freeway,the morphology of Siping City now seems like a pentacle.The city should make full use of its traffic line which extends in all directions.All these indicate that the combination of urban morphology index and statistical data can be done to satisfactorily describe the process and characteristics of urban expansion.
  • ARTICLES
    Method of making statistics thematic maps based on FushionCharts and ArcIMS
    YOU Juan, ZHOU Yanbing, WANG Jihua, PAN Yuchun, ZHANG Wuming
    2010, 12(2): 248-253.
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    With the rapid development of Internet and WebGIS,there are more and more extensive applications of the WebGIS statistics thematic maps in recent years.ArcIMS provides a way to make the statistics thematic map and releases it through the network,but its functionality is still not perfect.It can only provide two kinds of charts,i.e.pie and column charts,the type is very limited,and the aesthetics is not strong.What's more,as the feature-map and statistical thematic chart are generated on the server side at the same time and then transfered to the client side,so the load of server is high and network transmission is slow.The aim of this study was to provide a new method for making statistical thematic maps using ArcIMS combined FushionCharts,which is a chart component.The author refered to nearly 40 kinds of SWF files provided by FusionCharts,wrote a class which was used for converting the data's format into xml,then sended the SWF file and XML to the client,analysed through the flash plug-in of the client to generate statistical thematic chart,used the spatial geological place points coordinates,overlaid to feature-map which was made by ArcIMS on the server side to form the statistical thematic maps finally.This method generates the feature-map and thematic statistical chart on the server and client side,respectively.Compared with the traditional methods using ArcIMS only,it has a more simple production process;includes nearly 40 kinds of beautiful,highly interactive types of statistical thematic charts,making the form of charts abundant and visual,meeting the user's requirements more fully.In addition,it generates the feature-map on the client side separately,without the generation of thematic statistical chart formed on the server,so it is a good way to reduce the load of the server,making double the speed of network transmission.At last,a specific example of using this method is given,showing that it can make multiform,dynamic and good looking statistical thematic maps easier and faster.
  • ARTICLES
    Fast Image Processing Method of UAV without Control Data
    GONG Adu, HE Xiaoying, LEI Tianjie, LI Jing
    2010, 12(2): 254-260.
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    Unmanned Aerial Vehicles(UAV) images quickly processing method without other GCP(Ground Control Point) data is discussed in this paper,and the UAV images of Disaster Areas of Wenchuan Earthquake in Sichuan Province are used as the typical test data source.In the handling progress,only the images and auxiliary data recorded by the UAV system itself are used to stitch and rectify the image mosaics.The main work contains images,which were recorded by digital camera on the UAV and auxiliary data,which were recorded by GPS(Global Positioning Satellite) system on the UAV analyzing,flying area blocking,image auto-stitching after blocking,image rectifying and image mosaic.The image auto-stitching is the key point of the whole research.Firstly,a detailed analysis on UAV images and auxiliary data is done.With the analysis result,many questions are put out,such as the number of images is so large and UAV image distortion is worse than that of traditional photogrammetry.These bring a lot of difficulties to the work,that the normal methods can not be used.Base on this situation,a new strategy is proposed in this paper.That is,in the small area,which is determined by the experiment,the auto-stitching method base on image matching is raised,then the regional images after auto-stitched are corrected according to auxiliary data of UAV.In the image matching progress,SIFT(Scale-Invariant Features Transform) algorithm is applied in order to achieve high efficiency and high precision.Then pseudo center points collected from auxiliary data are used to rectify the regional images.From the result image after stitching and rectifying,a conclusion can be drawn that the relative accuracy is high and the mosaic image is visually dislocation-free.
  • ARTICLES
    Multi-resolution Remotely Sensed Image Segmentation in Combination with Spectral and Shape Features
    WANG Min, WAN Qiming, ZHANG Daqian, ZHANG Qingfeng
    2010, 12(2): 261-268.
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    The redundant image details of high resolution remotely sensed imagery may cause more distinct spectral diffusion and noise distribution.It sometimes makes traditional pixel-based image analyzing methods inapplicable.Nowadays,object-oriented image analyses have become a hot research topic in the field of remotely sensed image processing and interpretation.It is because the latter has stronger capability to deal with noise,and it can introduce more abundant image features and expertise knowledge in analyses.The first and most important step of object-oriented image analysis is image segmentation,which segments an image into many visual homogenous parcels.Based on these parcels,which are "objects",not "pixels",more features can be extracted which facilitate the succeeding image interpretation.In this study,we designed and implemented a multi-resolution image segmentation method combining spectral and shape features with reference to the basic ideas of eCognition,a famous object-oriented image analyzing software package.The algorithm includes the following steps.(1) The initial segmentation parcels,called the 'sub feature units',are obtained with rainfalling watershed algorithm,which is of very fast speed and fair segmentation precision.(2) A fast region merging technique is used to merge these sub feature units in a hierarchy way.Based on the sub feature units,a merge cost function integrating spectral heterogeneity and shape heterogeneity is designed to guide the merging of parcels.The use of the shape features is to make the merged parcels more regular in shapes.A scale parameter is used to control the merging process,which stops a merge when the minimal merging cost of parcels exceeds its power.A multi-resolution segmentation can be implemented by setting different scale parameters,for smaller scales mean less cost while merging which create smaller parcels,and vice versa.Several experiments on high spatial resolution remotely sensed imagery were carried out to validate our method.In most cases,the multi-resolution segmentation produced highly visually homogeneous image objects with arbitrary resolutions on different types of data.
  • ARTICLES
    Parallel Fusion for Remote Sensing Images Based on Grid Services
    ZENG Shaobin, XIE Chuanjie, LI Jiaqi, SHI Lei
    2010, 12(2): 269-274.
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    The bandwidth of network has been greatly improved owing to the development of network,a large number of remote sensing images released on the network as shared resources which could be accessed online.And with the development of network,the traditional remote sensing image processing methods are not well adapted to the new resource-sharing model,so,it is an easy choice to make improvement on software functions.Gird computing is being more attractive environment for parallel image processing on web because of the high bandwidth and plentifully shared computing resources available on the Grid.Grid computing is a resources sharing environment on the web,and resources dynamic changing is an essential characteristic of the Grid,not only the usage of the resources is changing but also new computing resource can join or leave dynamically.As the Grid is a frequently varied system,data updating,nodes joining or leaving,the load of node changing and the performance of the network changing will all affect the performance of the Grid services,so only these dynamic information be collected promptly and the execution plan timely adjustment be made that the high performance process could be guaranteed.The main idea is to utilize the Grid architecture WSRF(Web Service Resource Framework),choose a best plan to do parallel image processing according to the status of services,and provide efficient remote sensing image fusion service.In this paper,a service-oriented architecture for parallel remote sensing image on Grid is presented at first,and different kinds of services of the architecture are introduced briefly.There are five components for the architecture,which can trace and record resources dynamic changing on the Grid and provide an environment for parallel remote sensing image processing.Then,a parallel remote sensing image fusion algorithm on the architecture is presented in detail.The algorithm generate optimal parallel execution plan adaptively for the parallel image fusion according to the resource changes on the Grid.The equations for evaluating the costs of different execution plan are also presented.At last,a testing Grid environment is setup and the partial result image of the image fusion of a TM image and a Spot image is illustrated.
  • ARTICLES
    High Resolution Remote Sensing Image Retrieval Using Quin-Tree and Multi-Feature Histogram
    WAN Qiming, WANG Min, ZHANG Xingyue, JIANG Shen, XIE Yulin
    2010, 12(2): 275-281.
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    Nowadays,vast amount of remote sensing data have been acquired with the rapid development of Earth Observation System(EOS).It has become a serious task to manage and use these data for most RS and GIS applications.The content-based retrieval system for remote sensing images(CBRSIR) has become resultingly a hot research field with the potential to retrieval interesting information from image databases automatically and intelligently.In this work,we put forward a new remote sensing image retrieval approach by using multi-features including image color and texture.Firstly,a given image is processed by principal components analysis and then decomposed by Quin-tree,which splits large-scale remote sensing imagery into sub images.Secondly,texture features of each image block are extracted via multi-channel Gabor filters,and the standard deviation and third moment of each sub image are extracted as color features.Then,color and texture histograms are constructed based on sub images.Finally,we compare the similarity of the color and texture histograms between the query example and each one in the image database.If the total similarity is higher than some threshold,the image will be returned.These images are sorted according their similarity as the final retrieval results.This approach is validated using high resolution remote sensing images.
  • ARTICLES
    Estimation of Wetland Vegetation Biomass in the Poyang Lake Area Using Landsat TM and ENVISAT ASAR Data
    WANG Qing, LIAN Jingjuan
    2010, 12(2): 282-291.
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    Wetland vegetation is one of the important components of wetland ecosystems,and its biomass is the key indicator of the health status of the wetland ecosystems.The sensitivity of near-infrared band to biomass decreases as the vegetation density increases.In contrast,there is no significant change in red spectral reflectivity,so the vegetation index cannot reflect changes in high-density vegetation area.When using C-band SAR data to estimate the biomass in areas with low-and middle-biomass,the radar backscattering from the wetland soil with a great deal of water behind the canopy results in the phenomenon that different biomass have the similar total radar scattering coefficient in the radar images.In this paper,we have done research on the sensitivity to the biomass for three kinds of optical remote sensing vegetation indices NDVI,RVI and DVI,the use of improved MIMICS model to simulate different scattering components of wetland vegetation,and on seting up the simulation database of all components of wetland vegetation backscattering.Then we offer a method with Landsat TM and ENVISAT ASAR alternating polarization data,selecting the vegetation index DVI=0.45 as the threshold to divide the wetland of Poyang Lake into two parts: the vegetation with low leaf density and high leaf density.For DVI<0.45 the areas with low leaf density,there is high linear correlation between vegetation index and biomass,so we apply the statistical analysis to build a linear regression model using the samples.For DVI>0.45 the areas with high leaf density,due to the decline of the effects from the soil backscattering behind vegetation canopy,it can be used in C-band approximate microwave scattering models in the canopy to estimate these vegetation biomass such as Carex,Reed.Finally,the entire wetland biomass of Poyang Lake is approximately 2.1×109kg.The accuracy of the result is higher than the previous result that only uses optical remote sensing data in high leaf density.Hence,combining the merits of optical and radar remote sensing can effectively enhance inversion accuracy of the entire wetland vegetation biomass.
  • ARTICLES
    Land Cover Change in Baiyangdian Wetland
    WANG Jing, LU Shanlong, WU Bingfang, YAN Nana, PEI Liang
    2010, 12(2): 292-300.
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    Baiyangdian is the largest natural lake and the typical inland wetlands in the North China Plain.In recent 40 years,Baiyangdian wetland is facing serious environmental problems,such as water shrinking,ecological function degradation,biodiversity reduction,and water pollution.In this paper,by using the CORONA spy satellite image in 1964,Landsat MSS images in 1974 and 1983,ETM+ image in 2002,the land cover change and driving forces of Baiyangdian was analyzed.The eCognition 5.0 was used to classify the remote sensing images of the study area,and the spatial analysis superimposed tools in ArcGIS 9.0 was used to obtain the land cover conversion data in different years.The result indicated that the area of the Baiyangdian wetland is decreasing in the study period.The area in 1964 is 407.3km2,and 274.63km2 in 2002.Furthermore,great change happened in the water area.In 1964,the water area is larger,with the value of 346.75km2.In 1974,the water area decreased to 94.65km2.In 1983 and 2002,the water area is smaller,with the value of 67.27 and 46.86km2 respectively.The main factor that causes the land cover change is the variation of water supply.There are two main reasons to impact the water supply of the study area.One is climate change,including the decreased precipitation and the increased evaporation.The other one is human activities,such as water consumption for urban development,land use change,the construction of reservoirs and water transfer projects.This paper applied the early CORONA spy satellite images to Baiyangdian wetland land-cover change analysis,solved the problem of lacking in data of early time period in the region.It made the research time back up to 1960s.Furthermore,the multi-temporal satellite remote sensing data used in the study improved the temporal resolution of land cover monitoring,and provided basic data for performance of regional land-cover change analysis.
  • ARTICLES
    GIS Analysis of Ecological Security Evaluation in Xinfengjiang River Valley Using ALOS Data
    SUN Caige, ZHONG Kaiwen, LIU Xulong, XIE Liang
    2010, 12(2): 301-308.
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    In this paper,a method of ecological security evaluation in Xinfengjiang River Valley was studied,and a theoretic framework was set up with RS and GIS technology.Based on ALOS image,10m×10m grid was taken as basic unit,while township as comprehensive unit.Then Pressure-State-Response(PSR) framework was improved and GIS was used to acquire 18 evaluation factors information,such as settlement pressure,road pressure,mining pressure,water quality,vegetative cover index,rivers density index,land deterioration index and so on.Ecological security index was calculated next by different models in every grid and every town in order to make ecological security classification maps.According to the study,ecological security index is divided into six levels.levelⅠmeans very safe,and level Ⅵ means very unsafe.From levelⅠto level Ⅵ,the ecosystem services become less and less perfect,the ecosystem structure become less and less complete,and the capacity of ecological restoration and reconstruction reduce gradually,while the destruction degree of ecological environment and the possibility of ecological disaster increase gradually.The results show that(1) Ecological security in Xinfengjiang River Valley is good from global aspect.It accurately reflects the status of ecological security in Xinfengjiang River Valley.(2) Security level distribution in was not balanced,which has evident regional characteristics.The worried status of ecological security were in residential、industrial and mining area,while states of Xinfengjiang reservoir area were better.(3) 82.43% of this area is in safe,while about 17.57% of the area is in warning.Despite the overall relatively good situation,insecurity has also reached an area of about 217.600 8km2,which accounted for 3.8% of the watershed area.Of the 41 towns in the river valley,there are 35 towns are safe,5 towns are in warning,with only one town unsafe.The study also shows that RS and GIS technology has positive significance for protecting and improving the ecological security in Xinfengjiang River Valley.