With urban development,the quality of eco-environment in city is being paid more and more attention.This paper takes Nanjing city as an example.On the basis of analyzing TM image in 2000 and CBERS-2 image in 2004,the land cover information in different years can be extracted by man-machine interaction.The result of analysis of the variations of land covers and eco-environment show that in 2000,the main parts of land use are residential area,paddy field and dry land while in 2004,the main parts are residential area,dry land and woodland.The paddy field reduces greatly and the inhabitant area increases obviously.The main parts of change in land use types are paddy field and dry land.In terms of changing rates of land covers,paddy field and transportation land change most quickly,and their dynamic degrees are-8.61 and 5.17.The different category changes are complex,and 20 pairs of transformation relations exist in eight major classes(except naked rock).The values of EV in these two years have been computed,being 0.3871 and 0.3799.The results show that eco-environmental quality in Nanjing is descending slightly.Moreover,biological abundance index increases by 10.43,indicating that the biological diversity changes a lot positively during four years.Vegetation cover index decreases by a big margin,indicating that the vegetation cover reduces obviously.

The human-induced land use changes have a great impact on the global climate changes and thus is the focus of the various studies.Currently,the study on the dynamics of land use usually takes the advantages of the remote sensing technology and Geographical Information System.In this study,the land use changes in Fuzhou city and adjacent areas during the last 20 years were investigated using remote sensing technology based on three Landsat TM images acquired in 1986,1996 and 2006,respectively.A Maximum Likelihood Classification algorithm was applied to classify the images and the classification accuracy was further enhanced with the assistance of the high spatial resolution SPOT Pan images and the Geographical Information System.The change detection technique has been used to reveal the changed land use areas and to obtain conversion matrixes of land use classes using the post-classification comparison method.The result clearly reveals that the land use changed dramatically during the study period due to the rapid economic development and urbanization process of the area.The main land use classes,such as built-up land,arable land and forest land,have changed at various degrees.The rapid spatial expansion of the urban areas has resulted in the sharp decrease in arable land,making a distinct character of the land use change of Fuzhou District.Further combination of the remote sensing data with the socio-economic data of the study area indicates that the main driving forces to the land use changes of the area are fast industrialization,population growth and the government decision making.

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.

Collaborative Forest Fire Fighting Decision-Making experts may come from different organizations or different fields,having different knowledge structure and preferences,which gravely hinders the effective communication in the decision-making group.In this paper,ontology was introduced in Collaborative Forest Fire Fighting Decision-Making to solve semanteme compatibility during collaborative decision-making procedure.The prevalent construction methods of domain ontology were analyzed.According to the accomplished methods and in light of engineering method and life cycle approach in software development,the construction method of forest fire ontology was presented,which includes three phases of specification,conceptualization and formalization.Taking forest fire fighting decision-making application as an orientation,according to the analysis of decision-making content and the discussion among domain experts,based on the classification system and combined structure of conception,modeling primitives including concepts,relations,functions,rules,etc were abstracted from relative fields such as forestry,meteorology,fire fighting,and geography,and shareable,comprehensible,reusable,and conception models were built.Forest fire fighting domain ontology was built with ontology modeling tools. Parsing and visualization tool of ontology was designed and developed,Semantic Network Graphic and tree diagram visualization approaches were applied to the tool,with which users can display the relationship of conceptions(such as the inheritance relationship,the relationship of classes and instance and the relationship of classes and property et al.) by realistic visualization fashion and query connotation of them.The result of research serves as a basis for the communication between different disciplines or domains for effective cooperation.That would provide a reference for study on forestry and fire fighting informatization,would provide an important way in semantic level for forest fire management and the emergency demand decision-making.

Beijing has been the Capital of the People's Republic of China for 60 years.Especially in the last 30 years after China carrying out the opening up policy,Beijing has become not only the political and cultural center of China,but also the center of transportation and communication of China.Beijing is orienting to the whole world.The city's radiation and agglomeration construction is boosting up constantly.Beijing joins with Tianjin,Shanghai and other coast cities by advanced network of air,rail,road and telecommunications..The flow of people,logistics,information and capital extends in all directions.Beijing is developing so fast that Hi-tech development zones,central business district and financial centers are emerging like the rain-after bamboo shoots in spring.Satellite towns have been formed around Beijing and new housing projects and ecological resorts have been built up.Beijing,as a metropolitan,is now ready to host the 2008 Olympic Games.

Due to its opening and self-described format system,abundant spatial data expression technology,flexible application mode generation method,GML quickly plays an important role in many GIS research and application directions such as spatial data modeling,transmission and exchange,integration and sharing after several years of development.This paper deeply analyses research development of GML in China on aspects of domestic GML related research project,doctoral and master's degree thesis as well as published Chinese papers by core journals.In addition,this paper proposes challenges confronting domestic GML research and application and crucial problems to be resolved in the direction of GML development from three aspects: GML specification research,GML technology research and GML application research.From the analysis of research subject,the focus of GML research has changed from the initial expression of GML data,spatial data modeling of industry,spatial data conversion and integration and visualized research of GML,to GML's internal mechanism which based on the principle of the core technology of GML,the way to realize GML and interoperability between applied technologies.From the analysis of doctoral and master's degree thesis and the Chinese papers published on core journals,we can see that the research of GML was emphasized on application before 2004 but at of GML technology and combination between it and space services after 2004.The research of GML application was mainly concentrated on the support of WebGIS framework,spatial data sharing and interoperability and so on,while that of GML technology focused on GML's storage,index,query,compression and pattern matching and so on.Papers and studies on GML put forward the challenges and urgent problems in domestic GML research and application from three aspects: the GML specification,GML technology and GML application.In GML norms aspect,China should promote the institution of national relevant sharing standards based on GML.In technical research aspect,domestic researchers should strengthen the technique and method's study on GML resolution,GML storage,GML query,GML index and GML compression and transmission.In applied research aspect,it is very necessary for professionals in GML field to establish professional application mode,fractionize the applied layers of spatial data,and improve the shared obstacles in GML application system.

The inherent uncertainties in the real world and the limitation of human cognition are the primary factors of the abundance of uncertainty existing in the judgment of sciences to objectivities.An amount of uncertainties exist in the spatial data describing the spatial entity,including temporal-relative location data and attribute data,some of which may seriously distort the reliability of products.The remotely sensed imagery contains uncertainties caused by unexpected factors during the acquiring process.If only measuring the degree of uncertainty but ignoring the spatial-temporal distribution features,it is not easy to describe accurately and completely the uncertainty in remote sensing information.Representing uncertainty information from the point of view of visual sensation is one of the important sections of modeling uncertainty.The uncertainty visualizing techniques will help users to explore uncertainty in raw data and size,distribution,special structure and tendency of uncertainty.Using existing computer visualization technologies to express uncertainties is an intuitive and effective way.In this paper,these visualization techniques include three types of visualization: static visualization,dynamic visualization and feature visualization.Based on the Landsat-5 TM remote sensing image covering the Chinese Yellow River delta area and its classified data,we investigated several techniques discussed above.

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.

There are several optical and radar small satellites in HJ constellation which is developed in China,and they will be launched gradually since the end of 2007.In the constellation,HJ-1C is planned to be launched in 2008,on which an S-Band SAR is loaded.The S-Band SAR will work at 3.2GHz,VV-polarization and incidence angle range is 25°～47°.Backscattering coefficient retrieved by radar is very sensitive to soil moisture,because soil dielectric constant has a strong influence on backscatter coefficient,and soil moisture content is a determined factor to soil moisture.Because the number of influencing factors is larger than the number of observations,inversion become an "ill" problem,the result is that conventional physical model can not be used to obtain the model inputs directly.So,physical model must be simplified for acquiring an input from the model output.Following this method,based on the configuration parameters of HJ-1C and SAR sensor,soil moisture change retrieval method is studied using AIEM（Advanced Integral Equation Model） simulation data in this paper.Firstly,the applicability of traditional method（based on Simple Scattering Model） for soil moisture change retrieval using single-polarization SAR data is analyzed at S-Band（totally four bands data is checked,namely,Ku-band,C-band,S-band and L-band）,the result shows the method is applicable at S-band,ever has better outcome than using C-band data.Then,a comparison is performed when using different soil moisture parameter as input in the method,the result shows the best result achieved when vertical-polarization amplitude is used.Finally,the validation is done using simulated data,the result shows that almost 80% of the data has an error less than 5%.The result of this paper will benefit to the quick-application of HJ data after its launched.

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.

1999年10月14日,中巴地球资源卫星01号升空,2006年中国资源卫星应用中心自主研发的数据处理实验系统投产,迅速提高了数据产品的生产能力和效率。通过对IRMSS图像的去噪声干扰,CCD图像的M IF补偿。在敦煌定标场连续两年开展CBERS-02星CCD与法国SPOT-4 HRVIR1的交叉定标试验,及时将结果上网公布,拓展了数据定量化应用的广度和深度。2007年7月数据产品分发已突破20万景①。在CBERS图像应用中,贵阳市率先应用于1∶10万森林调查,扬州市开展了主要农作物的长势监测,北京市进行了密云水库蓄水面积的变化监测,北京市绿地动态监测等。

To put Geographic Information System(GIS) technology innovation stratagem in practice,can not only satisfy the requirement of geographic information better,but also promote the development of geographic information industry.In this paper,three modes of GIS technology innovation were analysed firstly,that is technology push mode,requirement pull mode and mixed mode.Introducing the other technology and the deepening of application were the main causes of GIS technology innovation.Then,the methods of how GIS company actualizes technology innovation were presented,such as to absorb new science and technology in the process of GIS research;put oneself in right place according to GIS market situation and real requirement of users;cooperate with users and scientific research institutions,the other GIS companies,and related sector of society;and perfect the mechanism of GIS technology innovation.Finally,the function of government in carrying out GIS technology innovation stratagem was expatiated,such as to support baisc research in GIS domain,cultivate new type of technical personnel in GIS technology innovation,build up technology innovation platform for middle and small GIS companies,and create good environment for GIS technology innovation activities.

This paper analyzes a newly proposed remote sensing index—the Enhanced Water Index(EWI),by Yan et al.(2007) and discusses the creation of a water index.The EWI was constructed by the ratio of the green light band to the sum of the near infrared(NIR) band and midddle infrared(MIR) band,i.e.,EWI=[(Green-(NIR+MIR))/[(Green+(NIR+MIR)).The evaluation of the EWI was through the application of the index in two images,one without atmospheric correction and the other with the atmospheric correction,and then the comparison of the results of the two enhanced images.Furthermore,the EWI-enhanced water images were also compared with the MNDWI-enhanced water images.The evaluation shows that the EWI failed to effectively enhance and extract the water features in the atmospheric-corrected image,while the MNDWI can work effetely in either corrected or uncorrected images.Many small open water bodies,such as ponds,lakes and city inner rivers,were omitted in the EWI-enhanced/extracted image.Obviously,the neglect of the atmospheric effect on the image resulted in the failure.In addition,the construction of the index is not reasonable.The increase in the concentrations of the suspended solids and algal chlorophyll can notably raise the reflectance of the NIR and MIR bands by water.Therefore,the difference in the reflectance between the green bands and the sum of the NIR and MIR bands can be significantly reduced and the EWI values of many such water bodies can be close to zero or even can be negative.Consequently,instead of being enhanced,these water features were depressed and even removed from the EWI-enhanced image,and thus resulted in the omission of the water features in the extracted EWI-water images.Therefore,in order to avoid uncertainty,any new water index to be created should be tested using atmospherically-corrected image beforehand.Moreover,the water components have also to be taken into account when constructing a water index.

From a perspective of ecological civilization construction,regional economic development and macroeconomic coordination,this paper suggests that the Grand Canal project is a successful example in developing wetlands and lakes in the great plains of eastern China.It is the main water line for transportation in ancient time,a landmark project in the era of national farming civilization,a political,economic and cultural artery that guaranteed North-South reunification since Sui and Tang dynasties,a main artery of China's historical development and a symbol of great ecological civilization in China.The approximate length of the Grand Canal is 3 500 km,it is a compliance among natural environment,stream pattern of landscape and micro-topography of the plain.After 2,500 years of hard work,it has become a great water transportation system in China.At present,about 900 km are still at service.More than 300 million tons of cargos are handled every year.It is still a main route for transportation between the north and the south.The Grand Canal runs through nearly 6 provinces,2 municipalities and 33 cities in eastern China,of which 18 are famous historical and cultural cities.These cities have changed simultaneously with the rise and fall of the Grand Canal.Water culture and landscape along the canal are still the characteristics and highlight of those cities and are basic factors making these cities suitable to live and eco-tourism cities.

This paper introduces the "Band/Image+GridGeometry+Metadata" structure which is brought forward to solve the multi-source remote sensing images management and sharing problems.A GridGeometry is a feature that represents the spatial information of a satellite image,and it can help to fulfill spatial operations without loading large volume satellite image.ISO 19115 is adopted as the metadata standard for different types of satellite images,and the metadata information is formatted into XML before storing or processing.Based on techniques mentioned above,finally,we design and implement the sharing platform for multi-source remote sensing images.The platform provides two kinds of service,i.e.direct images sharing service by the website and interoperation service by a series of accessible function interfaces which are encapsulated as web services complying with WMS,WFS,WCS,etc.

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.

Difference between plantation area and farming area of the design form and field form in the second countrywide farming survey is mainly caused by the difference of survey targets,survey time,sites selection,statistical calibers and technological measures.Differences also arose from the fact that investigators poorly comprehend the relationship among ownership,right of use and right of operation and can't distinguish farmer contract ration field,large foodstuff family and farming produce department contract plantation and land exchanges between farmers.The paper also listed many factors which may lead to the plantation area difference in the countrywide farming survey,such as land whole expropriation,land part expropriation,land void expropriation,land expropriation in advance,mass plantation occupied for city use,land consolidation,land protection and balance of occupation.

An effective image fusion technique can not only improve spatial details but also preserve the spectral information.Many research papers have reported the limitations of exiting fusion techniques.The most significant problem is spectral distortion.For IHS fusion,a common strategy is to match the Pan to the I band before the replacement,stretch the H and S bands before reversing HIS transform,or stretch individual I,H or S band with respect to individual data sets.In PCA fusion,the solutions are stretching the principal components to give a spherical distribution,or discarding the first principal component.By selecting these proper fusion techniques,successful results can be achieved for the fusion of SPOT Pan with MS images.However,these techniques are not efficient for the new high-resolution satellite images,such as IKONOS and QuickBird images.This study analyses the reasons for spectral distortion in the new high-resolution image fusion.The research reveals two major reasons.One major reason for the distortion is the wavelength extension of the new satellite Pan image.The radiometric difference between different sensors is also an important reason if the fusion images are from different sensor systems.Four image fusion algorithms have been employed to resolve the spectral distortion problem in the study of QuickBird image fusion.These are the filter-based algorithms such as Wavelet and SFIM transforms,and statistics-based algorithms such as Gram-schmidit and PCI pansharp modules.The experimental results show that although all these four algorithms have good spectral fidelity property,the statistics-based algorithms are generally more efficient than filter-based algorithms through the quantitative statistical analysis of spectral fidelity and the ability of gaining high frequency information.But the research result is only for QB image.

Vegetable and fruit are necessaries of people in daily life,whose safety problems are beneficial not only to the people's livelihood,but also to the competition capability of Chinese agricultural products in the international market.The safety problems of agricultural products for the 2008 Olympic Games in Beijing,have already been intensively regarded by the authorities.In this article,the concept of traceability logistics of agricultural products is brought forward by relating the traceability with the process of agricultural product logistics,and the solutions of it are put in practice to use IC card to record and store the traceability information of agricultural products logistics.On this basis,a prototype of traceability logistics system is constructed by using COM pattern and described in detail from database construction,system framework,structure of function,and structure of component.Finally,the system is put into effect with the data of the study areas in Beijing.It is proved that the solution of traceability logistics in agricultural products with the support of GIS is feasible and efficient,which provides an innovative idea for how to establish an efficient,credible and banausic traceability system of agricultural products in China.

Land cover information plays an important role not only in social-economic development but also in scientific research area.With the development of the information technology,remotely sensed images provide main data sources for land cover information and knowledge extraction in real time.While there are lots of land cover classification systems in the world facing to different research targets and objectivities and with the crossing of multi-disciplines and expanding of the research area,more and more land cover classification systems are designed.This causes the difficulties for datasets' exchange,integration and fusion which use different classification systems.The problems facing land cover classification systems are similar with the problem of metadata standards.Faced with this problem,ISO TC211 designs an extensive metadata standard framework for geographic data,and draws up the ISO Metadata Standard 19115.Enlightened by the ISO 19115 metadata extensible framework,the paper brings forward the land cover extensible classification framework.The framework is composed of 3 tiers,i.e.,land cover core classes,schema classes and application profile classes.The core classes are derived from the main international land use/land cover classification system.Schema classes inherit and extend core classes.Extensive principle and methods are designed in this framework.This ensures many application classification profiles can be extended from the core classes and schema classes easily while the designed extensive land cover classification system should be tested and perfected through more and more real applications.

Mean solar spectral irradiance of satellite is an important parameter for the computation of appearance reflectance.In this paper two methods are used to compute the mean solar spectral irradiances of CBERS-02 CCD,one method is that using the radiation transfer software SBDART to simulate the curves of exo-atomosphere solar spectral irradiances,with the combination of the spectral response curve of CBERS-02 CCD,the mean solar spectral irradiances of band1 to band4 are computed;another method is to use 6S model for the computation.To valid the computing methods,these two methods are used to compute the mean solar spectral irradiances of TM and ETM,compared to the data provided by the government,it is showed that the result of the first method is better than that of the second one.Taking the scene obtained on August 24th, 2005 as an example,the appearance reflectance is computed,after the atmospheric correction using 6S model,the ground reflectance is retrieved,and compared to the measured reflectance value,the relative error of band1 to band2 is 0.01%,and the relative error of band4 is 4%.

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.

ArcGIS 913中包含的JavaScript APIs使最终用户能够将来自于ArcGIS Server的基于地理信息系统的网络服务与其它的网络内容相结合。该项新功能使得在客户应用中部署ArcGIS Server的数据和服务以及在企业中传递空间分析变得更加轻松自如。ArcGIS 913是首个提供mushup功能的GIS软件。以下是ArcGIS Server913新改进方面和新功能中的一部分内容。新的REST和JavaScript APIS这些API将大大简化用户的开发时间并使用户能够快速和方便地为地理信息系统的Web应用程序提供mashup能力。

Ecological mapping in the tropics is difficult due to the heterogeneity of the vegetation,the nature of the terrain which is often highly dissected,and general problem of determining ecological boundaries which may be indistinct,even to a field observer.There are no studies in the literature discussing the successful mapping of vegetation or habitats over large areas.In the last 20 years,two habitat surveys in the form of vegetation maps have been completed by Hong Kong government departments and private consultants,with inadequate accuracy and poor results.Since these previous projects used only medium spatial resolution sensors:Landsat and Satellite pour l'Observation de la Terre(SPOT),it may be possible to produce more accurate ecological maps using the new generation of Very High Resolution(VHR)satellite sensor images.Traditionally,habitat mapping has used Aerial Photographic Interpretation(API).However,45 air photos are required to cover the study area,Shing Mun and Tai Mo Shan country parks in Hong Kong,compared with a single IKONOS scene.Additional advantages of IKONOS include spatial,spectral and temporal consistency.Therefore,if a suitable methodology for automatic habitat mapping can be developed,reduced costs and less processing time would be required.This study attempts to develop a methodology for detailed ecological mapping based on a suite of integrated image processing techniques,and with stated accuracy levels,for IKONOS images-"Multi-scale object-oriented segmentation with decision tree classification"(MOOSC).The results show that 95% overall accuracy was achieved using API and 94% was achieved using MOOSC method when the results were referenced to GPS field data.These findings support the applicability and feasibility of MOOSC method,and it was only one third of the cost comparing with API.

Tobacco enterprise is a special enterprise,which has strong correlation to regional geography.But in the past research and application,the combination between tobacco and GIS is limited to the use of digital maps to assist cigarette distribution.How to comprehensively import GIS to construct digital tobacco is the main research aspect in this paper.Geographical information service is the new stage of geographical information development.The current research work emphasizes particularly on the study of pattern.However,the concrete application research for geographical information service with enterprise and commerce is seldom reported.Tobacco industry is the important source of finance and revenue in China.Digital tobacco is the new stratagem stage for tobacco industry informatization.Geographical information service entering the digital tobacco will bring about revolutionary changes for tobacco industry and correlative related commerce.The paper discusses concrete application content of enterprise geographical information service combining with digital tobacco.And then it gives corresponding framework design.The practice in this paper proved that this research may bring great benefits for tobacco company and government departments,including national revenue.

In order to study the influence of different bandwidth's remote sensing data on estimating chlorophyll-a concentration in waters,this paper analyzes and calculates the correlation coefficient between normalized reflectance of different bandwidth and chlorophyll-a concentration based on real-measurement hyperspectral reflectance.With constant increase of bandwidth in a scope of 75.93nm,it has found that the maximum correlation coefficient decreases by degrees,the maximum positive correlation band moves to long wave,the maximum negative correlation band moves to short wave while estimating chlorophyll-a concentration in waters.As the bandwidth changes in the scope of 31.60nm,both the maximum positive correlation band and the maximum negative correlation band will keep a relative stable state.Finally,through contrasting the mean and standard deviation of different bandwidth's correlation coefficient,we think 723.51nm^~33.00nm is the best band range for estimating chlorophyll-a concentration.This will provide important reference value for band setting of remote sensing sensor and band choosing of real chlorophyll-a estimation by remote sensing in water.

Linear Spectral Unmixing(LSU) could extract endmembers such as canopy or other objects at pixel level,but the accuracy of LSU which is presently used in multispectral and relatively broad spectral range data is not available to quantitative research,so an improved technique for LSU which is based on the classification of land cover was employed in this study.First the ASTER image covered the study area was spatially segmented by five types of land cover maps.Sequentially based on the endmembers selection procedure the LSU was applied to each sub-ASTER image and full image respectively for subsequent comparative analysis.Because the number of objects in sub-image was less and the spectral variance of the same objects was smaller than the full image which is commonly used in traditional LSU,so this improved technique could break the limits of the traditional multispectral data which has less bands for hyperspectral analysis,and also,the mixed objects which occur in traditional LSU algorithm could be unmixed effectively by the new method.We concentrated our study on site of Fuzhou in Fujian Province equipped with ASTER data set.Only the first nine bands in VNIR and SWIR of ASTER were selected for subsequent analysis because the five TIR bands were not relevant to the reflectance of land surface objects. The result proved that an improved inversion accuracy of canopy abundance of-6.4% was achieved comparing with traditional Linear Spectral Unmixing(LSU).Furthermore,following the inversion of canopy abundance using the improved method,density slice was applied to the canopy abundance image and the spatial distribution of canopy abundance was subsequently analyzed.

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.

People usually use qualitative terms to express spatial relations,while current geographic information systems(GIS) all use quantitative description to store spatial information.The abilities of current GIS to represent spatial information about geographic space are limited,and it is inconvenient for GIS users without professional training.The next generation of GIS could be intelligent GIS built on Na1¨ ve Geography.It will act and respond as a person would,and therefore can be used without major training by new user communities to solve day-to-day tasks.In order to bridge the gap between natural-language terms and the computational model of spatial relations,a complete understanding of the relationship between the ambiguous natural-language representations and the geometric spatial relations of geographic objects is requisite.A human-subjects test was conducted to find out how natural-language descriptions of spatial relations of linear objects are determined by the geometric configurations of the objects.A series of maps,with each map showing two linear geographic objects,were displayed to the human subjects,and a sentence describing the spatial relations of the two objects was provided to the subjects.Comparing the sentence to the map,the participants determined whether this sentence described the relation correctly,and chose their agreement from given options ranged from "strongly agree" to "strongly disagree".The answers chosen by the human subjects were converted to agreement degrees which represent the plausibility that certain spatial relations can be described by the spatial predicates,so the results could be analyzed quantitatively.The results indicated that both topology and metric properties influent people on choosing spatial predicates to describe spatial relations,but they have different effects on various spatial predicates.Some spatial predicates are mainly affected by topological relations,while metric measures do not have significant effects.Other spatial predicates are primarily affected by topology metric details,while topology only has secondary effects on them.The categories of geographic entities were also found to have effects on the natural-language description in some cases.

Soil erosion not only represents the intense geomorphologic process of the Loess Plateau but also the symbol of the environment deterioration,soil erosion and the geomorphologic evolvement are interdetermined.Present research shows gully plays a leading role in the catchment morphologic evolution and ground surface dissected extension.The semi-arid cathchment of the Loess Plateau of China is severely affected by soil erosion as it is revealed by the commonly occurring deep and wide gullies.Recent studies in the loess hillgully terrain area show gully erosion has a very significant contribution to total soil loss.Traditionally,gully erosion had been measured using field survey techniques,the advances in computing powering digital photogrammatric solution are now offering an affordable and cost effective way of estimating the gully erosion.This paper used the digital elevation models(2 m grid),which constructed from multi-date(1959-1981 and 1999)aerial photographs(1∶55 000,1∶20 000 and 1∶35 000)as a tool to compute the sediment yield by gully erosion in a small catchment of 9.06 km2 located in the Loess Plateau of China.Soil loss of two periods:1959～1981 and 1981～1999 was estimated from computed gully volumes using soil bulk density,compared the measured data with the estimated result of which,valued the DEM-based techniques for estimating soil loss,indicated that it should be possible to rapidly estimate soil loss,and recommendations were made for future applications of DEMs for assessment of soil loss as well.Based on the estimated results the impacts of human activities were analyzed:human activities is a double-edged sword which can improve the environment and accelerate the erosion at the same time,people still needs to do more to reduce soil erosion.Combined the statistic data with the DEM-based spatial analysis,it is clear that most of the soil loss are due to overland flow,mass movements and gully deepening。