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  • 2009 Volume 11 Issue 2
    Published: 25 April 2009
      

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  • ARTICLES
    CAO Feng,DU Yunyan,GE Yong,LI Deyu,WEN Wei
    2009, 11(2): 139-144.
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    Geo-spatial relations reflect the complex association between geographical phenomena and environments,so,are very important in dealing with geographical issues.They can be generated according to geometric attributes of spatial phenomena,such as distance,direction,connectivity,similarity etc.Also they can be generated based on combinations of geometric attributes and non-geometric attributes such as statistical correlations,spatial autocorrelations,space interactions,spatial dependencies etc.There are still other geo-spatial relations arising from non-geometric attributes of spatial phenomena.Extracting geo-spatial relation rules effectively helps to improve the accuracy and efficiency of solutions of geographical issues.This paper discusses both the expression of geo-spatial relations and the extraction process of geo-spatial relationship rules based on rough set theory.To illustrate the extraction process of the rules,we take the land use vector data of the Pearl River Delta in 2000 as an example to extract the geo-spatial relationship rules of urban areas and rural residential areas in Shenzhen and Hong Kong.
  • ARTICLES
    CHEN Songlin,WANG Tianxing
    2009, 11(2): 145-150.
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    Fuzhou was chosen as our study area.Using Temperature/Emissivity separation algorithm,land surface temperatures(LST) were retrieved from ASTER(Advanced Spaceborne Thermal Emission and Reflectance Radiometer) data set which was collected on April 6th,2004.Two methods named equal interval method and mean-standard deviation method were employed to divide land surface temperatures into four,five and six classes respectively.Synchronously,the domain of urban heat island(UHI) was determined according to its different definitions.Then multi-angle comparisons covering the structure,spatial distribution and the tiny undulation of the UHI delimitated by different methods were applied to choose the better methods.The result indicated that the percentage of the UHI area delimitated by both methods was fluctuant with the class number,while for the intensity of the UHI,mean-standard deviation method was less sensitive to the number of thermal field than that of equal interval method.Furthermore,the former was better than the latter in describing UHI spatial distribution and details.Based on standard deviation of land surface temperature against its mean value,the mean-standard deviation method,to some extent,likely minimized the problems that resulted from the inconsistent time periods of collecting remote sensing data in studying the multi-temporal urban heat island.However,our research was only a preliminary case study,more details and uncertainties about these methods and results needed to be further studied.
  • ARTICLES
    GAO Song,LU Feng
    2009, 11(2): 151-156.
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    A path finding heuristic algorithm of road network hierarchy is discussed in this paper,which adopting a road-cost evaluating function and the road hierarchy is an important factor considered here.The path searching process is conducted on as higher hierarchies as possible,so as to restrict the searching scope.Hence,the algorithm greatly speedups the path searching process,gives results under controllable accuracy levels,and makes the results consist with human cognition.Compared with conventional hierarchical spatial reasoning algorithm,the algorithm presented in this paper can be implemented more easily,with similar efficiency and accuracy results.The theoretical analysis and case-study validate the algorithm.
  • ARTICLES
    FAN Xiaochun,ZHANG Xueying,LIU Xuejun,SHEN Qijun,FAN Xiaoming
    2009, 11(2): 157-162.
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    At present there are two significant problems in the field of intelligent transportation systems,i.e.algorithmic efficiency and transfer routines.First of all,this paper describes route selection behaviors of passengers and the characteristics of city traffic networks,and then presents the public traffic network-transit matrix based on key stops.Secondly,based on the shortest path algorithm,a public traffic network-transit matrix and a non-transfer matrix are introduced to design the public traffic transfer algorithm.In this algorithm,the public traffic network transit matrix aims to decide which temp label notes are potential label notes,and non-transfer notes are always considered as the notes of the shortest path,in order to improve the performance of classical shortest path algorithm(Dijkstra).Finally,a case is used to evaluate the performance of this algorithm.The experimental results indicate that the proposed algorithm achieves better efficiency than the Dijkstra.And much more reasonable transfer frequency is obtained.It is believed that this algorithm can be used in general transit networks,especially high transfer-cost networks.
  • ARTICLES
    LV Long,HUANG Zhenfang,WU Jiang
    2009, 11(2): 163-168.
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    Rapid increasing tourists in tourism regions have brought the biggest pressure to tourism ecology capacity in recent years,conflicting seriously with our efforts of environmental protection.In order to realize the environmental protection and sustainable development,it is necessary to study the relationship between tourist activities and tourism ecology capacity.Utilizing nonlinear theory,this paper attempts to show the dynamic relationship between the tourism activities and the tourism ecology capacity of tourism area.Through setting up the nonlinear dynamic model of the tourism activities and tourism ecology capacity,their essential relationship is also analyzed.The results show:(1)To achieve sustainable development of the system,it is prerequisite that the sum of the environment self-renovation and manual recovery is larger than the severity of external pollution,and that the tourists growing rate remains at a lower level.(2)The tourism ecology capacity is limited;hence,the tourists a landscape could accept are limited.If tourists exceed a certain threshold,the ecosystem would be unbalanced and deteriorated.Therefore,it is vital for harmonious development of the system to restrict the quantity of tourists,promote the protection and improvement of the environment and popularize good behavior of tourists.(3)This paper gives a detailed analysis with the Wulingyuan Scenic Spot as an example.It suggests that the government should provide reasonable planning,which would avoid the constructive exacerbation of ecology in tourism region and help the manual recovery of unbalanced environment.
  • ARTICLES
    WANG Jinfeng
    2009, 11(2): 169-175.
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    Map analysis may reveal new information in spatial data,and the map could be mental map,geometric map,summary map and so on.The mental map displays the map in human mind of the distribution of objects in the real world map in Euclidean space,by a transform between the two spaces.Geometric analysis infers the properties of studied object by geometric measurement,operation and graphic statistic,e.g.buffer,overlay,proximity,mass center,shapes,as well as comparison of spatial patterns.Summary mapping tries to filter out and summarize the baseline features of spatial objects based on qualitative induction and intelligent approaches,and based on observations and understanding and physical underling mechanisms of amount of existing maps and patterns.
  • ARTICLES
    LIAO Shunbao,ZHANG Sai
    2009, 11(2): 176-182.
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    As one way to process geo-data,spatialisation of attribute data has become one of research focuses in GIS field.Spatialisation of attribute data can produce errors to a certainty like other data processing methods.It is very important to put forward a suit of evaluating index of errors for spatialisation of attribute data.In this paper,the evaluating index is composed of three parts which are corresponding to three different stages in spatialisating of attribute data: data source analyzing,spatialising modeling and data products.Evaluating index for data sources includes density of data observatory,density of contour line,and density of polygon pattern and equality of data.Evaluating index for spatialising model includes correlation ratio,significance of model(correlation ratio test;F test;t test)and estimation error of the model.Evaluating index for spatialised data products includes mean value,maximum value,value distribution range and spatial distribution of errors.Errors based on samples are divided into absolute errors and relative errors.These indexes are foundation for integrated evaluation of errors for spatialisation of attribute data and could enhance quality of data products.Among these evaluating indexes of error for spatialisation of attribute data,errors of spatialised data products are determined by precisions of data sources and spatialising models.The same precision of data sources with different precision of spatialising models leads to different precision of spatialised data products.The same precision of spatialising models with different precision of data sources also leads to different precision of spatialised data products.Therefore,error evaluating for spatialisation of attribute data should be carried out on the three stages consisting of data sources,modeling and spatialised results.
  • ARTICLES
    MING Xiaona,LONG Yi,QIAN Chengyang,ZHANG Ling
    2009, 11(2): 183-188.
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    Natural language can be applied freely and flexibly,which would not be restrained by the environment and locations,and it is a fluent and quick communication method.Thus,reasonably applying natural language in Geographic Information System(GIS) to realize the human-computer interaction between users and system will contribute to the development of GIS intellectualization.Natural language will transmit the GIS commands in the form of the characters,in which a vast number of spatial data and information as well as GIS basic operation instructions are loaded.Therefore,GIS command analysis based on constrained natural language aims to extract the information related to GIS operations from input sentences.According to the thought of rule matching,the essay marks the words with classifications,based on map browsing,data reading/writing,data collections,information inquiry,spatial analysis functions and word collocation relations.With sentence segmentation,sentence normalization,rule matching and function mapping to analyze the GIS commands from constrained natural language input.Through case study,it indicates that,the rule matching method can efficiently eliminate the semantic barriers existing between unstructured spatial information in natural language and structured spatial information in GIS.As a result,it will contribute to further applications of natural language in GIS.
  • ARTICLES
    YOU Songcai,SUN Chaoyang
    2009, 11(2): 189-195.
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    Digital watersheds of China are extracted based on SRTM30 in this study.Flow direction is calculated by applying D8 algorithm.There are two schemes in specifying the watershed boundary extraction.One is to extract watersheds in the area including China and its adjacent regions;the other extracts watersheds only within China.The results show that the first scheme is much better in reflecting watersheds crossing the state boundary.Based on the first scheme,main watersheds of China have been clearly identified and the area of each of them has been calculated.Totally,there are 8302 independent watersheds within China,no matter how small they are.Of them,there are 23 watersheds with an area over 50000km2,make up of 82.09% of total land area of China.Different from the traditional perception that Yangtze River watershed is the biggest one in China,Inner land watershed in northwest China is the biggest one,followed by Yangtze River watershed,Yellow River watershed and Songhuajiang River watershed,etc.Meanwhile,the potential calculation error for watersheds with an area more than 5000km2 has been analyzed,which is less than 1.73%.Compared to the traditional division of Chinese watersheds and the result extracted based on GTOPO30,it is verified that SRTM DEM has a higher quality in extracting watersheds of large regions such as China,and the area calculated has a higher credibility.Further work can be done based on more detailed DEM data to extract sub-watershed.
  • ARTICLES
    XIAO Rulin,SU Fenzhen,WAN Qing,DU Yunyan,LIU Yeseng,LIU Yuanyuan
    2009, 11(2): 196-201.
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    Ice-jam is a kind of complex natural landscape and disaster.The 3D visualization technology is an important way for ice-jam information management,monitoring and forewarning,which has signality for ice flood control and mitigation.In this study,based on the underlying structure of Multipatch data model,we probe into the technical solution to 3D visualization of ice jam,and then present a practical approach to realize the complex ice-jam 3D modeling and visualization.It determines the ice surface coverage on river by simulating its formation mechanism and gets height(z)values of each boundary vertex based on DEM data interpolation.Then it subdivides ice surface according to the natural formation process of ice-jam and randomly generates ice-cone or ice-prism with stochastic height,azimuth and obliquity in light of its irregularity.Finally,it pastes the texture with field pictures and achieves 3D visualization by overlaying the ice-jam 3D models in 3D scene utilizing virtual memory and texture compression and caching technology.As a case study,the technology is applied in an actual system developed and it realized the ice-jam's automatic 3D modeling and visual management,which verified the approach we suggested.
  • ARTICLES
    FAN Zhewen,LIU Musheng,SHEN Wenqing,LIN Liansheng
    2009, 11(2): 202-208.
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    Research on eco-environment vulnerability assessment contributes to ecological environmental conservation and development.Taking Jiangxi Province as a case study,this research has developed the index system of eco-vulnerability from the perspective of the meaning and the cause of eco-vulnerability and in accordance with the eco-environment situation of Jiangxi Province.The indicators were weighted by the principle of the spatially principal component analysis.With the support of GIS,the integrated index evaluation was applied in assessing eco-vulnerability.The result shows,in 2005,the moderate vulnerable area dominates and shares 85.36% of total land area in Jiangxi Province;the mild and intensive vulnerable land area occupy 14.64% and 0.002%,respectively.And the vulnerability of Jiangxi Province was distinct-spatially distributed.In general,Jiangxi Province belongs to the moderate vulnerable area.Taking county as assessment unit,the results show that the integrated vulnerable degree lies between 20 and 40 in 7 counties which belong to mild vulnerable zone: Nanchang County,Xinjian,Jinxian and De'an around Poyang Lake Plain;and Xiajiang,Taihe and Ji'an located in Jitai Basin;and the other 82 counties or cities of Jiangxi Province with index of 40-60 are moderate vulnerability.The eco-vulnerability of Jiangxi Province widely and apparently varies in spatial distribution.Mountain areas in upstream of the five rivers have more intensive eco-vulnerable environment,while Jitai basin and Poyang Lake Plain are the contrary,and the hilly areas in middle and lower parts of the five rivers fill in with the mild vulnerability.The conclusion of this research is that the vulnerable environment is put down to the natural conditions here,and the stresses from human activities play as catalyst to intensify the vulnerability.
  • ARTICLES
    TANG Xianming,LI Yuanyuan,QU Shouli
    2009, 11(2): 209-215.
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    3D geoscience modelinGIS the key technique issue to the visualization of 3D geological data using GIS.Based on analysis of construction process and data structure of 3D visualization system,using ArcSDE as engine of spatial data and ORACLE 10g,"Petroleum exploration geodatabase of Sichuan Basin" is established.With Skyline TerraDeveloper,the software system "3D geographical information system for petroleum exploration based on 3D global model" is designed and developed.By integrating geographical database,areal geology database,surface engineering database,remote sensing image database,stratigraphical database,fault data,logging database with 3D terrain modeling,the system realized such functions as data management for petroleum exploration,3D terrain modeling,visualization of 3D geological model and 3D navigation for petroleum exploration data.It is a visualization platform that assists the design and analysis for geologists and the technologists.
  • ARTICLES
    ZHANG Zengxiang,WANG Xiao,WANG Changyao,ZUO Lijun,WEN Qingke,DONG Tingting,ZHAO Xiaoli,LIU Bin,YI Ling
    2009, 11(2): 216-224.
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    Land cover change is an important part of global change.Aiming to present situation of land cover in China,according to terrestrial ecosystem characteristic and remote sensing mapping,in this paper we put forward a remote sensed land cover classification system.In order to combine the accuracy of interpretation and speediness of self-classification,we integrated remote sensing classification,alternating interpretation and assistant information analysis,under the control of polygon's position and borderline which provided by higher accurate land use data,with the data source of MODIS vegetation index products in 250m resolution,to realize national land cover remote sensing mapping in 2005.Using field survey data,the accuracy assessment is also implemented.Results show that: each class of land cover map has an exact precision,and the map can represent the characteristic and distribution trend of land cover in each region on the whole;the polygon patterns matched the image geography characteristics quite well.The overall precision of national land cover map is 91%,and the precision of each class is over 89%.
  • ARTICLES
    PENG Guangxiong,GONG Adu,CUI Weihong,MIN Tao,CHEN Fengrui
    2009, 11(2): 225-230.
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    The study area is located in Miller county,Yunnan province,China.An experiment to select the appropriate classification method for multi-temporal remote sensing images was done.Typical classification methods including Object-Oriented Classification(OOC),Back Propagation Neural Network(BPNN),Spectral Angle Mapper(SAM),Maximum Likelihood Classifier(MLC),and Comparison After Classification(CAC)were tested in this experiment.In this study,using two-phase remote sensing images of CBERS02B-CCD and Landsat-5 TM,the suitability and accuracy of typical methods to deal with multi-temporal images classification were compared,based on different phenological characteristics of sugarcane,corn and paddy.Using full sample test method,visual interpretation results were used as reference data to validate the accuracy of different classification methods.The experimental results show that the order of overall classification accuracy from high to low is OOC,BPNN,SAM,MLC,and CAC,and the Kappa accuracy of them is 0.655、0.635、0.631、0.601 and 0.577,respectively.As it is easy to identify paddy,its accuracy is higher than that of sugarcane and corn.The order of accuracy of paddy for different methods is as the same as the order of overall accuracy,the highest and lowest accuracy of paddy is 0.706 and 0.621,respectively.The accuracy curve position between the accuracy of various land covers and the overall accuracy are consistent for MLC and CAC,and the overall accuracy of CAC is the lowest one.The accuracy of corn for OOC is the highest one with Kappa of 0.611.The Kappa accuracy of sugarcane for OOC,SAM and BPNN is 0.594,0.575 and 0.575,respectively.In general speaking,for the remote sensing classification of Multi-temporal Images,OOC is the best,BPNN and SAM is better,MLC and CAC are the worst.The conclusions of this experiment have some guidance to select the appropriate classification method for multi-temporal remote sensing images.
  • ARTICLES
    ZHOU Xiaocheng,WANG Xiaoqin,JIANG Hong,WU Bo
    2009, 11(2): 231-236.
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    Jiulong River,the second largest river in Fujian province,is the mother river of economic region in the south of the province.Assessment on index and model of eco-environment which suit to Jiulong river basin is built based on multi-source and multi-temporal remote sensing data from Landsat TM,ASTER and "Beijing-1" satellite(DMC+4 micro-satellite) and additional data.Eight factors involving soil erosion,vegetation,soil brightness,elevation,slope,rainfall,humidity and accumulated temperature were extracted from remote sensing images,DEM and meteorologic data.Based on summing eight factors by multiplying respective weights,eco-environmental quality and its change maps for three periods during fifteen years from 1989 to 2003 in Jiulong river basin are acquired for the first time.The result shows:(1)Eco-environmental quality is good as a whole in three periods for 1989,1998 and 2003.There is the largest area for excellent eco-environment in 2003,up to 3425.36km2 and the smallest area for that in 1998,amount to 2010.31km2,while the largest area for bad eco-environment in 1998,up to 504.43km2.(2)The eco-environmental quality firstly declined from 1989 to 1998 and then improved from 1998 to 2003.Specially,common characteristic of eco-environment in Jiulong river basin is that the middle region is better than south and north areas,and the west is better than the east.Eco-environment of two regions is poor all the time.One region is sub-basin Xinqiao brook and Xi'nan brook,the other is at the estuary and circumjacent region of Jiulong river basin.Activity of human being,which is driven by economy benefits,is main factor to change the quality of eco-environment in the past 15 years.The study also shows that not only 3S technology gains the larger advantage over traditional field investigation in cost and time but also owns high quality result for eco-enviroment evaluation.
  • ARTICLES
    XU Xinliang,SU Fuyan,ZHUANG Dafang,JIANG Dong
    2009, 11(2): 237-243.
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    A rare freezing rain and snow disaster attacked most parts of southern China from 15th January to 9th February,2008.The extremely bad weather has not only destroyed people's daily life and production badly,but also influenced local eco-environment greatly.In this article,we monitored the impacts of southern ice and snow process on eco-environment with a case study at Zixing County in Hunan Province by making use of remote sensing and field survey methods.The results showed that the vegetation was destroyed badly and NDVI decreased for a large scale,and the decreased area of NDVI occupied 54.12% of the total land area.The forest ecosystem was damaged badly.Except for some parts of shrub,all forest ecosystems were affected by disasters,which added up to 3.02 million hectare.It took on the following characteristics,coniferous trees were damaged more seriously than that of broad-leaves trees,young forests were damaged more seriously than mature forests,alien species were damaged more seriously than native species,planted forests were damaged more seriously than that of natural forests.On the other hand,the comprehensive risk degree of geological disasters increased,because soil water content increased and slope stability was weakened,which maybe induced geological disasters,such as landslides and collapses,occurring frequently in engineering construction regions and near edge of forests and steep-slope regions.
  • ARTICLES
    ZHANG Tao,SU Fenzhen,YANG Xiaomei,SUN Xiaoyu
    2009, 11(2): 244-249.
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    In recent years,the coastal regions of China have frequently experienced algal blooms,which are harmful or otherwise toxic because of their potential threat to human being as well as marine organisms.This article mainly focused on the following aspects:(1)analyzed the MODIS spectral characteristics of four typical kinds of seawater: clear water,turbid water,red tide water and mixed water;(2)analyzed the merits and shortcomings of band ratio method for red tide extraction;(3)proposed a new red tide information extraction method: Supervised Classification method based on Band Ratio(R4/R3) and MODIS band 1,4 and 3.Based on this method,successful information extraction has been carried out for the Pearl River Estuary algal bloom event in Feb.2006.
  • ARTICLES
    YAN An,JIANG Pingan,WU Hongqi,MA Lichun
    2009, 11(2): 250-255.
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    The technology to manage remote sensing image data through the spatial data engine has been very mature,but how to organize reasonably,manage effectively and share easily of multi-source remote sensing image data need to seek more effective methods.In this article,according to the same spatial resolution and different spatial resolution,we designed logically multi-source remote sensing data storage model,and established multi-source remote sensing image database,based on the analysis of the different types of remote sensing image data.Physical storage model,image data compression and image pyramid structure of remote sensing image data have been described.This article introduces methods of designing multi-source remote sensing image data storage logically on the same spatial resolution and different spatial resolution.That is the methods,which to organize and manage image data through establishing the relationship between multi-source remote sensing images by metadata table,based on the classification of the spatial resolution of remote sensing image data.The methods have been used successfully in this study,which will provide reference for design and construction of multi-source remote sensing image database.