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  • 2008 Volume 10 Issue 2
    Published: 25 April 2008
      
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  • ARTICLES
    The Analysis of Land Use Change and Driving Forces of Taihu Lake Rim
    LI Min, SUN Zaihong, YANG Sujing, QIAO Weifeng
    2008, 10(2): 136-141.
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    Taking the Taihu Lake Rim as a case,this paper analyses the progress of land use change and the driving mechanism from 1996 to 2007. Supported with mass data,it analyses the trend,the comentropy,and the equilibrium of regional land use change.Since 1996,the adjustment of land use structures in Taihu Lake Rim has been slowed down at a steady rate.From 2004,the land use structures of this area are developing reasonably and smoothly.It demonstrates that the land use change is mainly affected by the economic development,the agriculture intensification,the progress of urbanization,the increase of population and policies.
  • ARTICLES
    Case Study of Application of Principal Component Analysis for Comprehensive Analysis of Water Quality in the Taihu Lake
    ZHOU Xueli, DING Xianrong, CHENG Ligang
    2008, 10(2): 142-146.
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    This article uses the principal components analysis method to carry on the quantitative analysis to the water quality data of Tai Lake station,had discovered the water quality indexes which act on principal components variable in token of water quality condition,and has analyzed the primary causes of the effects on water quality and each principal component environmental significance,finally obtains the comprehensive score calculated by the every principal score and sorted.The results show that the top four principal components,which are extracted from original factor information and can account over 90 % of the total variance,can substitute 11 index factors completely to analyze water quality in the Taihu lake comprehensively.The results also turn out that principal component analysis method has overcome the difficulty of the analysis by synthesis multi-dimensional indicators,and possibly will be one important method of water quality comprehensive analysis in the future.
  • ARTICLES
    Research on Remote Sensing Monitoring and Early Warning System about the Cyanobacteria Blooms in Taihu Lake
    WANG Shen, JIANG Nan, HU Bin, WEI Qingyu
    2008, 10(2): 147-150.
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    Cyanobacteria blooms in Taihu Lake have exerted impacts on the ecological,economic and social aspects of the surrounding areas.The monitoring and early warning to the cyanobacteria blooms make great sense to the administration of Taihu water environment.Based on research of the remote sensing monitoring and early warning on the cyanobacteria blooms,the paper is in terms of building the information system to analyse the process about cyanobacteria blooms in Taihu,system analysis is presented according to the workflow of the processs of monitoring and early warning to the cyanobacteria blooms based on remote sensing,then framework of the system is addressed,which is programmed by computer language in C# and IDL,and the framework has the advantage of containing modules easily.In order to enhance the information system flexibility,two key techniques are adopted including the system integration and soft pattern.System integration technique can merge the IDL into framework of the system,and the soft pattern technique is able to organize modules in the framework efficiently.
  • ARTICLES
    Quantitative Retrieval of Solid Suspended Matter Concentration Using MODIS 250m Band
    LV Heng, WEI Xiaohong
    2008, 10(2): 151-155.
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    Based on the 250m bands of MODIS and near-real-time sampling data,Solid Suspended Matter Concentration(SSMC) are quantitatively retrieved using linear model.The result shows that the SSC of Taihu Lake has the highest correlation coefficient with MODIS band 1 and the lowest correlation coefficient with MODIS band 2;of all the 250m-band combinations,SSMC has the highest correlation coefficient with M1+M2,so the SSMC quantitative retrieval model was built through the correlation analysis.This plays an important role in the SSMC time-space distribution analysis using high time-resolution remote sensing data.
  • ARTICLES
    The Modeling for Dynamic Blue-green Algae Blooms Prediction Based on Remote Sensing
    WEI Qingyu, JIANG Nan, LU Heng, WANG Sheng
    2008, 10(2): 156-160.
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    As the blue-green algae blooms in the Taihu Lake of China are more and more frequent,they have become a great threat to eco-environment,aquatic breeding industry and human health.In this paper,by summarizing current research conditions about the blue-green algae blooms forecast,with MODIS data and ground collecting data in Taihu Lake in China,the authors use a new concept to construct the blue-green algae blooms prediction model.This concept considers the optical characteristics of the four periods of the blue-green algae blooms and also the effects of the meteorologic environment.The model is hopefully to be used to the forecast and early warning in the future.
  • ARTICLES
    Study of the Quality-infection and Quality-index System on the Information of Space Governance in Digital Agriculture
    ZHOU Li, GU Ruiqing
    2008, 10(2): 161-164.
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    This paper discusses the information quality-index of the space governance in digital agriculture.Digital Agriculture space governance originated in agricultural development in the renewal and transformation of land structure,any of the agricultural modernization and transformation planning and implementation,we need space admittance for updating project approval and space management control decision-making evaluation.Based on the evaluation of agricultural modernization and transformation,the establishment of access to space admittance and space management decision-making evaluation index system was realized.Through analysis of the factors affecting data quality,it is designed to the quality index system of the space governance in digital agriculture.
  • ARTICLES
    A Fractal Study on the Urban System of Xinyu in Jiangxi Province
    LI Jian, HU Mingxing
    2008, 10(2): 165-170.
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    Urban system planning is an important part in Chinese urban planning system.Compared with traditional planning methods,some modern mathematical theories and methods are more exactly and effective in aiding urban planning design.Based on the fractal theory,this paper analyzes the scale structure and spatial structure of the Xinyu urban system and calculates the fractal dimension of the urban scale structure,the aggregation dimension and correlation dimension of the spatial structure.Then,according to the result of the analysis,some suggestions on the Xinyu urban system planning are put forward.
  • ARTICLES
    The Study on Genenralization Algorithms of Settlement in the Mobile Environment
    WANG Meizhen, SHEN Jie, SU Kun
    2008, 10(2): 171-176.
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    The restrictions of hand-held devices and the characteristics of wireless network environment require improvement of the map to adapt to the new conditions.As an important tache in the process of map production,map generalization is the challenge we have to face in the moible environment.In this paper we probe into the efficiency of part of generalization algorithms on settlements,and test the usability of them.We also attempted to design the algorithm on settlement which takes the user's context into account,including user's task,user's location etc.Finally we proved the usability of the algorithm based on the given case.
  • ARTICLES
    Research on Service Discovery Mechanism of Geography Sharing Network Based on Semantic P2P
    HU Bin, JIANG Nan, ZHAO Gang, WANG Shen, WEI Qingyu
    2008, 10(2): 177-182.
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    The advantage of P2P structure is fast at discovering and getting service.And the advantage of GeoOntology Repository is helpful to make semantic reasoning and to solve the conflict of geographical semantics.So,in order to alleviate "single point of failure" of central system based on SOA,this paper combines semantics P2P with SOA to publish distributed web services instead of using UDDI of SOA to central publishing service.By creating the geographical ontology and introducing geographical semantics P2P into SOA,this paper extends the service bus of SOA into geographical service bus(GSB).The service discovery of GSB is based on semantic P2P,and the new service discovery mechanism is implemented in GSB.All these details are encapsulated in GSB,so it is transparent for each service attached to GSB.The communication way among services is the same as the way using SOA.This way can let the legacy system upgrade smoothly.So our prototype not only holds the advantages of SOA on interoperability and transparent use of services under distributed heterogeneous geographical information sharing systems but also utilizes semantics P2P to complete the auto discovery task.Our method also provides an innovative idea for large scale sharing geographial data and services of science data sharing platform.
  • ARTICLES
    Validation Model of ASAR Speckle Noise and Evaluation Effect of Speckle Noise Filtering
    WANG Junzhan, ZHANG Youjing, BAO Yansong
    2008, 10(2): 183-189.
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    The existence of speckle noise on the ASAR(Advanced Synthetic Aperture Radar) images has exerted passive effect on the extraction of any quantitative information from the ASAR images,hence making the ASAR images ineffectively utilized.In this paper,based on radar signal transmission theory,the power probability distributing function of ASAR is deduced.For the multiplying noise model,it is validated by theoretic deduction and experiment data.Based on the noise model,different methods and filtering windows are used to reduce the noise.Comparing each filtering result with smooth index,edge keep index and so on,it is found out that the best effect is 7 pixel ×7 pixel of the Enhanced Lee filtering method.
  • ARTICLES
    Organization and Indexing Method for 3D Points Cloud Data
    LU Mingyue, HE Yongjian
    2008, 10(2): 190-194.
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    Being the primary data source,3D points cloud is also an important means to describe and express the geographic objects and phenomena in 3D GIS as well as to perform model building.And the effective organization of the points is the basis for its operation and analysis.Therefore,in this paper,3D points are arranged and sorted according to a specified rule,and then organized by a compound structure of spatial octree and balanced binary tree,which greatly speeds up the query process based on the 3D coordinate,and lays a solid foundation for the further analysis of 3D points data.This paper also unifies the compound structure in both memory and database.And a case study has proved its validity.
  • ARTICLES
    Design and Development of a 3D Ore Body Wire-frame Model Editor
    SONG Renbo, JIANG Nan
    2008, 10(2): 195-199.
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    Ore body modeling is one of the most important contents of mine visualization.In the process of ore body modeling,model editing is the most crucial step.From the perspective of software development,this paper explores the 3D wire-frame model ore body editor of the designs and introduces development methods,development environment,modeling methods,spatial data models,key technologies in model editing,and then discusses the concrete implementation process of HCI editing of the ore body wire-frame model.The editor has been able to map the ore body profile contours in 3D interactive visualization environment,and rapidly builds the contours of the ore body wire-frame model.Finally,as examples,mine ore section photograph demonstrates the effectiveness and easy operability of the editor.
  • ARTICLES
    GIS-based Waterfront Resources Evaluation of the Yangtze River in Nanjing
    YANG Jing, LI Manchun, DING Xianrong, LIU Yongxue
    2008, 10(2): 200-205.
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    Waterfront resource is an important component of land resource in China,and resource evaluation is the major work in waterfront resource studies.In China,the studies began at the end of the 1980s and focused mainly on the lower and middle reaches of the Yangtze River.In those methods,quantitative analysis and GIS tools have been applied.It is impractical to analyze the waterfront resource only according to the natural conditions and economic conditions.In order to gain both socio-economic and ecological benefits,in terms of the characteristic of Nanjing section of the Yangtze River,the factor index in this study is established including waterfront depth,stability of waterfront,water-behind land width,water resources protection areas and scenic resort and historic sites.In accord,the steps of resource evaluation are to cut cells,to evaluate each factor,and to grade waterfront.Applying GIS and ArcGIS Engine exploring tools,this paper implements the integrative evaluation along the Yangtze River in Nanjing,on the basis of which,index of individual evaluation is evaluated and reasonable division of waterfront cells.The evaluation results show that waterfront resource is rich,of which the fine parts take up around half of the overall length;furthermore,the fine parts are very concentrated which are fit to utilization.All the jobs can provide some consultation for scientific and reasonable utilization and exploitation of waterfront resource of the Yangtze River in Nanjing.
  • ARTICLES
    Research on 3D-Tense-GIS Pattern Based on Virtual Reality
    TANG Haitao, WANG Chuanhai
    2008, 10(2): 206-213.
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    The 3D scene is the main interactive interface of 3D GIS,and has an Earth scene and a valley scene,taking terrains and rivers as their two basic elements.It displayed DEM and river network on the 3D scene of the system.The water flow is displayed dynamically by reading the data of river network on sequential time,which represented the historic trace of tense-GIS.Also,we could add models which can be selected,transformed,removed and so on anytime on the scene by the integration of it with virtual reality.The functions of the query of terrain position at will and water level,water flow velocity and direction of any node of the river network at different time intervals were implemented which have a good capability of interactivity.
  • ARTICLES
    Copyright Protection of DEM by Means of DCT-based Digital Watermarking
    LIU Aili, LV Guonian
    2008, 10(2): 214-223.
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    A near-lossless,adaptive watermarking algorithm based on DCT is presented to protect DEM from theft and illegal reproduction.The contribution of this work is twofold: ①In order to improve robustness,the methodology is designed to embed a watermark in terrain lines.②As for the watermark embedding strength,it is decided theoretically in DCT domain by jointing the elevation precision of DEM and Watson perceptual model.And since different precision requirements are given to different relief forms,the watermark embedding strength is adaptive to relief forms.The experiments show satisfying results are not only in watermark transparency,but also in near-lossless of DEM precision and contour derived from watermarked DEM.In addition,this algorithm shows robustness towards JPEG compression,JPEG2000 compression and cropping attacks.
  • ARTICLES
    Study of Map Browser on Mobile Devices Based on Eclipse
    WU Chengyan, SHEN Jie, WU Jia
    2008, 10(2): 224-229.
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    We reviewed the actualities of the map browsing software in the mobile client,and then summarized the functions of the current map browsing software in the mobile devices and the developing technologies.We summed up the advantages of the way to use Eclipse and Mobile SVG on mobile devices,and proposed that how to design map application on the 3G phones based on Eclipse,EclipseME and SVG Tiny.In the paper we integrated J2ME and SVG into mobile GIS,using Eclipse as development platform,employing SVG as map expression language and applying XML to describe attributes.We inquired basic functions of the map browsing software in the mobile client,and then realized the browsing function and simple query function on the 3G phones.To manage the local data effectively we employed the simulation indexing mechanism and serializing means.We believe that this technology can be widely applied to mobile map service in the future.
  • ARTICLES
    River Basin Modeling and Water Resources Management Supported by MIKE BASIN——A Case Study of Dazi County,Tibet
    CHEN Gang, ZHANG Xingqi, LI Manchun
    2008, 10(2): 230-236.
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    Based on ArcView GIS,and using MIKE BASIN toolsets for river basin modeling and water resources management,this study takes Dazi County in Tibet a case.Using datasets of 50m×50m DEM,the paper calculates the ground rainfall-runoff in the study area(also sub-watershed of Lhasa River),further offers technical support for basin water resources management and dispatching.In the paper,the authors design a spatial network model for water supply-demand analysis and carry out watershed analysis on sub-watersheds.The study results can be displayed through thematic maps,graphs and tables.Through the above work,this paper provides a study framework for river basin water resources management.The results show: 1) Based on modern hydrological data collecting and modeling technologies,integrated watershed management is an inevitable choice for soil and water conservation,comprehensive treatment planning in sustainable utilization of water resources,and so on.Especially in watersheds of Tibet, the supply-demand contradictions in water resources utilization for agriculture and animal husbandry changed seasonally and dramatically,hence,scientific management of water resources has become a crucial issue.2) Digital river basin model is established on the basis of DEM,land-use classification data,ground meteorological and hydrological measurement data.3) Integrating GIS with simulation capabilities in MIKE BASIN provides simple and powerful tools for hydrological modeling and management of water resources.Using meteorological data of three meteorological stations(Pangduo,Tangga and Lhasa),the study established a geographic distributive model based on DEM for annual precipitation of Dazi County,for extracting the river network and concentration model of Lhasa River.Furthermore,the methods of hydrological time series analysis and hydrological simulation using MIKE BASIN are also provided in this paper.
  • ARTICLES
    The Analysis of the GIS Application in Urban Ecological Area Planning
    YANG Chunshun, SHEN Jie
    2008, 10(2): 237-241.
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    As a new technology,Geography Information System(GIS) is now an important tool applied in many fields.For the strong advantages at data storage,management and analysis,GIS is usually used as a database or an analytical method in urban planning.In this thesis,under the principles of landscape ecology,GIS is successfully used to analyze the ecologic substances in some "ecological area planning" during the early planning stage.And the results of the research will help to plan the spatial structure and developing intensity for the planning area.The basic mathematic equations come from landscape ecology,but it is GIS that plays a core role in putting the principles into the actual utilization,and also builds up a platform for applying the ecological theories into planning.
  • ARTICLES
    A Comparative Analysis of the Models in Urban Fire Station Layout Planning
    DENG Yi, LI Aiqin, DOU Wei
    2008, 10(2): 242-246.
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    This paper studies on the road networks based GIS service area analysis model and traditional model by comparison in urban fire station layout planning.As a case,this model has been applied in a large city's fire station layout planning.Research found out that there were not only some blind spots of fire station service areas in the layout of the status and existing fire station plan of this city,but also some service areas mostly overlapped.Based on the analysis result and in combination with city reality,an optimized adjustment scheme is proposed.
  • ARTICLES
    Extraction of Color Infrared Remote Sensing Images to Study Tidal Flat of Shanghai
    CI Hui, ZHANG Xingnan, RUAN Renzong
    2008, 10(2): 247-250.
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    Researches on the information of seawall and tidal flat have extensive prospect for application in many fields of hydraulic engineering construction,seawall management,tidal flat reclamation,flood fighting and so on.The tidal flat in Shanghai was extracted from the remote sensing images in this paper.After a series of processing procedures on color infrared aerial photographs,the information on the tidal flat was interpreted and analyzed using the method which combines the supervised classification with visual interpretation from the remote sensing images.The classified results were checked and revised based on the field investigation.It has provided an effective technical support for the tidal flat and foreshore department's management,greatly enhancing the accuracy of the data acquisition and the work efficiency.
  • ARTICLES
    Geometrical Features Extracting from High Spatial Resolution Images with Mathematical Morphology Methods
    LIU Sheng, WANG Xiaoyu, QIU Xinfa
    2008, 10(2): 251-256.
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    Based on mathematical morphology methods,two main algorithms were developed,such as multi-weighted combination filter algorithm with omnidirection structure elements and edge detection algorithm with multi-scale omnidirectional structure elements.By tracing the image edge,both raster and vector data objects were generated,and geometrical features extracting model was built.Results suggest that: the purposed algorithms can successfully process remote sensing images with high-spatial-resolution.The former suppresses noise and preserves details effectively;the latter resolves the contradictions between noise suppression and extraction of fine edge excellently,and anti-noise performance is strong.The extracted geometrical features information can be used in object recognition and classification of remote sensing image with its spectrums,texture,and statistics features.The extracted information can be used in the fields of GIS,photographic surveying,computer vision and the industries of meteorology,agriculture and forest,ocean,hydropower,land resources,and environmental protection.
  • ARTICLES
    Object-oriented Road Information Extraction from High Resolution Imagery
    TANG Wei, ZHAO Shuhe, WANG Peifa
    2008, 10(2): 257-262.
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    To extract roads from remote sensing imagery is one of the important parts in constructing and updating geo-database.Making full use of spatial information and structure texture feature of high resolution imagery,roads extraction is realized basing on object-oriented method.Firstly,mean objects are got using image segmentation.Then we build the relations between imagery and objects by spatial information in high resolution imagery.After that choosing several features such as spectrum,geometrics and texture,we construct knowledge database for road objects.It seems that the result has a better accuracy than traditional maximum likelihood based on spectrum information.It supplies a new way for roads extraction.
  • ARTICLES
    Application and Investigation of the Fusion of ENVISAT ASAR and CBERS02 Image Data
    LI Bingbai, YANG Shenbin, SHEN Shuanghe
    2008, 10(2): 263-268.
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    This paper analyzes and discusses the fused image which is the result of the fusion of ENVISAT ASAR and CBERS-02 CCD image data.Comparison of the three techniques of IHS transform fusion,principal components analysis fusion and wavelet transform fusion applied suggested that resolution merge of IHS transform method can get much better result,according to the visual interpretation of the resultant image.However,spatial resolution was attenuated in order to reduce the effect of speckle from the ASAR image.For the fusion image,which contains backscattering behavior from both VV polarization and HH polarization,and contains spectral information from the optical CCD data,it improves visual interpretation of the image and can be used for crop mapping with high mapping accuracy in the case discussed in this paper.
  • ARTICLES
    Remote Sensing Images Fusion Based on a&prime|Trous Wavelet and PCA Transformation
    LIN Hui, JIN Haitao, ZHANG Lianpeng
    2008, 10(2): 269-272.
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    As high-resolution remote sensing satellites come into being,it is hard to get good fusion results using original image fusion techniques.For example,the Principal Component Analysis(PCA) image fusion method is sensitive to the noise and limited to the fusion region.The traditional wavelet transformation fusion also causes spectrum information distortion to some extent,considering the effects of noise to the fusion image.Therefore,a′ Trous wavelet and PCA transform integrated remote sensing fusion method is studied where Quickbird multi-spectral image and panchromatic image are used in this article.The result demonstrated that it is better than other fusion methods by visual and quantitative analysis.
  • ARTICLES
    Drought Monitoring Index and its Application in Semiarid Area
    WANG Wenzhong, ZHANG Youjing
    2008, 10(2): 273-278.
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    In this paper,Enhanced Vegetation Index（EVI） and MODIS Land Surface Temperature（Ts） product data MOD11L2 were used to construct the Ts-EVI space,from which the Temperature Vegetation Drought Index（TVDI） was obtained as drought index to monitor drought in Sanhuajian area of the Yellow River on Mar.8th,Apr 2 nd.,Apr.13th and Jun.12th in 2002.Data from weather station and apparent thermal inertia（ATI） were also obtained to evaluate TVDI.A relationship（R2=0.734 5） was also obtained between TVDI and ATI.Land-use type and elevation were also studied.The results indicated that both of them were important influencing factors,different land use types had different distributions of TVDI,and the relationship between the height above 250m and TVDI was obvious.It was feasible to monitor the drought dynamic variations in semiarid area with complex terrain by using TVDI.