With the development of remote sensing,there are a few new types of sensors from which can acquire abundant new types of remote sensing data.These data have been applied successfully in many different fields of national economy.In this paper,applications of four new types of remote sensing data in uranium deposit prospecting,i.e.multi-spectral,high-spatial-resolution,hyperspectral and radar data,have been summarized.

The paper took Chifeng City of Inner Mongolia,a typical agro-pastoral transitional zone,as an example to investigate land use change process from 1988 to 2000 based on three periods of land-use data(1988,1995,and 2000) which were acquired from interpretation of TM images.The Land Exploitation Degree,the Land Conversion Degree,the information entropy,and spatial conversion matrix were adopted for finding characteristics of land use change especially land cultivation from grassland and cropland abandonment for grassland in two stages.The results showed that:(1)Land reclamation and grassland decreasing were main land use change processes in the whole stage.The area of cultivated land increased by 2424.12km²,and grassland reduced by 1959.65km²;(2)Comparing the two periods,in the first stage from 1988 to 1995,the changes between cultivated land and grassland were acute,and reached 2040.50km² and concentrated in the north of Aohan County,634.75km² in the opposite direct from cropland to grassland.Unused land also was conversed into grassland with a large area in Kerqin County;in the other stage from 1995 to 2000,the land use change speed slowed down.And main changes were the conversion of grassland and forest into cultivated land.There was an area of 828.50km² of grassland turning to be cultivated in Aohan County and the north of Linxi County;(3)The information entropy for land use structure in three periods were 1.290,1.301,and 1.304,respectively,showed that the order manner for land use system was in reduction.The study revealed the transitions of grassland cultivation and cropland abandonment from 1980 to 2000,and provided supports for accurate portrait of regional ecological security and human-environmental coupling system.

地球信息科学是面向21世纪形成的新兴学科。它是融合地球信息,遥感信息科学,全数字制图系统,地理信息系统、全球定位系统、虚拟现实多维可视化技术和信息网络等多学科的系统论、信息论和控制论于一体的科学体系。它以信息流为主要研究对象,探索地球信息机理,地球信息认知方法和地球信息时空图谱等,新学科生长点的科学研究。陈述彭先生从地球科学与环境科学和信息科学的高度,运用系统工程学原理,勤奋治学,长期潜心研究,将地理信息制图,遥感信息技术与地理信息系统等融汇贯通,拓展了地球信息科学研究的新途径。

A method to extract marine hydrographic characteristics based on line process is introduced in this paper.The program written in Visual C++ has already integrated in MaXplorer,which is a marine geographic information system platform developed by China.By this method,time series MODIS-SST data were used to extract sea surface warm front of Kuroshio in East China Sea.The seasonal change of the warm front location was analyzed based on the extracted results above.It showed that the seasonal change of the warm front location of the top layer of Kuroshio is not very evident in East China Sea in general,except in the area of about 30°N and the area near the northeast of Taiwan Island.Because the change of sea surface temperature(SST) in East China Sea in summer is relative small at an average temperature of 28℃,it is difficult to determine the locations of the warm front.The warm front locations in other seasons were occurred along the shelf break near the isobath of 200 meters.In north-eastern of Taiwan Island there is a clear curve which showed a cyclone pattern then an anticyclone pattern.The locations of warm front in winter were occurred in the relatively east part while in autumn,showed a relatively complicated route.

Geospatial data is a kind of strategic information resource and is widely used in economic,social and environmental applications.GIS vector data is closely related to the overall situation of socio-economic development and national security due to its high production cost and high precisions.In recent years,researches about copyright protection of GIS vector data mainly focus on copyright marking techniques.To meet the requirements of copyright protection for spatial data files,a real-time copyright protection scheme for spatial data files is proposed in this study,based on the Copyright Marking technology,especially on the Digital Watermarking technology which was only used for the authentication,file system filter driver technology and encryption technology,which can be used for dynamic encryption and decryption of data files and real-time detection of copyright marking.This scheme achieves the purposes to keep confidential,detect copyright marking in a real-time way and control access.In addition, it lowers the limitations on the capacity of copyright marking information and the robustness of embedding algorithms.

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.

Based on analyzing the spectral characteristics of the reduced alteration sandstone of gas and oil in Bashibulake uranium ore district,and the difference in illustrating the spectral feature between ASTER and ETM+ data,two kinds of technologic ideas were proposed to study the remote sensing reduced alteration information directly and indirectly.Following the two ideas,different effects in using ASTER and ETM data were compared respectively.Studies showed that both ASTER and ETM had equal and good effect in extracting the ferric information to reflect the law of reduced alteration of oil and gas indirectly,but in aspect of extracting the reduced alteration information,ASTER data showed obviously better effect than ETM+.Those enhanced reduced alteration information was of great significance in addressing the alteration law in Cretaceous system and uranium prospecting in the outer parts of Bashibulake uranium ore district.

GIS is now used in more and more fields.It is required that GIS should be equipped more function.People desire that the geo-data visualization should be with multi-angle,multi-point and multi-level.So GIS must be equipped with automatic data-generalization function.GIS relies on a rule database to realize automatic data generalization.In this paper we suggest that automatic data generalization is a process using a computer to process every database record according to the rules.Based on the production-rule method,this paper proposed a method named Rules Pre-stored to enable users to define application rule database.According to the method,a GIS application first builds a thematic rules database which includes all the rules with respect to a specific theme.The rules database is called the theme rules database.Different users of the theme could define their own special application rule database based on the theme rules database through the user interfaces.A demonstration was also given.To some extent,the self-defined rule database and the separation of code and rules were accomplished.The result shows that the research idea and technical route are feasible.

A digital elevation model(DEM) is a representation of terrain elevation as a function of geographic location.DEM inevitably contains errors,which are spatial variable and correlated.The usual error model is Root Mean Square Error(RMSE),whereas it is a global variable,and can not show the DEM error of each grid.In order to overcome the deficiency of RMSE,Dongzhi Tableland was employed as a test region,and an error surface about 6.25km2 was constructed based on the conditional stochastic simulation model(CSS).Water and soil loss level determination was taken as an example to validate the importance of CSS.The results indicated that the uncertainties in derived slope of the Dongzhi Tableland tend to be found in flatter areasthe slope error range is bigger than DEM error range,which indicates that the DEM error is magnifiedprobabilistic and fuzzy model shows that almost all grids are influenced by the DEM error in water and soil loss level determination.As a tool for DEM error analysis,conditional stochastic model can improve the user assessment of DEM error.

2009年11月25日是中国遥感应用协会专家委员会主任陈述彭院士逝世一周年,我们十分深切地怀念他。中国科学院院士、第三世界科学院院士、国际欧亚科学院院士陈述彭先生,是我国著名的地理学家、卓越的地图学家、国内外知名的地理信息系统专家、遥感专家,是我国遥感事业的奠基人。他开拓了我国综合遥感应用的广阔领域。1992年8月,中国遥感应用协会在山西五台山成立。它是全国遥感信息技术应用的行业性兼学术性的社会组织。其宗旨是团结全国遥感信息技术队伍,促进全国遥感信息技术的应用与发展。鉴此,中国遥感应用协会专家委员会于1996年3月在北京成立。

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.

The article quoted a number of important theory thoughts of independent component analysis and blind signal separation,classified and explained the distribution of probability density from the basic statistical characteristics of remote sensing hyper(multi-) spectral data and,established the connection between background and anomaly of image data.On this basis,it deeply analyzesed the spatial geometry structure of hyper(multi-) spectral data lattice distribution,concluded that high-dimensional space of remote sensing hyper(multi-) spectral data belong to low-dimensional geometry structure-"hyperplane" shape,and anomaly point group which includes alteration information usually dissociates out the "hyperplane".Then,the paper extended the signal-noise model of principal component analysis(PCA),proposed the dividable concept of background-anomaly signal sub-space of remote sensing image multi-data set high-dimensional,and gave the threshold estimated method of sub-space division.At the same time,it discussed the relationship among the pixel number of remote sensing image,the intrinsic dimension of multi-band data set,and the main background object number.Finally,through analysing two types of remote sensing data for Qulong area,Tibet,it explained the correctness and practicality of spectral data space low-dimensional structure and the application of analysing remote sensing hyper(multi-) spectral data to background-anomaly sub-space model.The results show that: although the spectral change of different landscape areas is complex,the low-dimensional geometry structure which spectral data space belongs to,and the practicality of background-anomaly(including noise) sub-space are the essential characteristics which they all possess.In a statistical sense,the alteration anomaly of remote sensing hyper(multi-) spectral data set is identifiable.

Walkthrough in massive terrain and image data is a key technology and a difficult problem of GIS,VR and Digital Earth,etc.Hardware-friendly LOD methods become popular with the development of computer hardware technology,such as SOAR,Chunked LOD,GeoClipmap etc.More and more LOD methods take account into large texture data.Based on current LOD algorithms and the development of computer hardware technology,the data block partition and the quadtree algorithm were used to establish pyramid.At the same time,large data accessing was improved by synchronous loading,LOD was controlled by texture resolution and the cracks between meshes were filled by adding skirts around each block.The results show that the rendering and updating of data is easier to be controlled,the geographical range of terrain and image data doesn't need matching exactly as before and massive data can be loaded and rendered quickly.

Basic morphological types of land geomorphology in China are made up of two indexes: altitude and relief amplitude.The altitude index is divided into 4 classes,that is: low altitude <1 000m,middle altitude 1 000～3 500m,high altitude 3 500～5 000m,highest altitude >5 000m;relief amplitude is divided into 7 classes,that is: plain < 30m,tableland >30m,hill <200m,low relief mountain 200～500m,moderate relief mountain 500～1 000m,high relief mountain 1 000～2 500m,highest relief mountain >2 500m.Then,the combined basic morphological types are 25 kinds.According to classification system of digital geomorphology,the classification indexes of altitude and relief amplitude are suitable for the whole Chinese continent;the above classified types from these two indexes can be calculated by means of multi-source data,such as DEM,Landsat TM/ETM etc.The experiments show: based on DEM data(such as SRTM-DEM 90m,equivalent to the scale of 1: 250 000),the adopted sampling unit which can be suitable for the whole Chinese continent is 4km²;corresponding to different scales respectively,5 types of sampling units,that is: 0.4,4,12,18,21km²,existing in the whole Chinese continent,can be attained by calculating form DEM data at different scales,such as 1: 100000,1: 4 000000 etc.Because of the complexity and multiplicity of Chinese geomorphology,the geomorphologic features of different regions can not be only reflected by means of elevation value and relief amplitude acquired from DEM data;hence,based on multi-source data such as remote sensing,the spatial distribution of 4 classes of elevation characteristics and 7 classes of relief amplitude characteristics in China can be well represented by means of the geomorphologic boundary acquired from artificial virtual interpretation;furthermore,the area and spatial distribution pattern of 25 kinds of basic morphological types of land geomorphology in China are achieved.

This study identifies the process of urban expansion and building density since 1932 using a combine of technology of RS and GIS.Urban expansion characteristics,urban land change from different building densities and its driving mechanism are analyzed.The results indicate that Yuan dynasty symbolizes the important stage of the beginning of urban development and construction.But the basic configuration of Beijing City was formed in Ming and Qing dynasty.Beijing City grew at a slow rate before 1984,and then the city began the first fast expansion under the socialist market economy during 1984-1992.Due to the implementation of the most severe farmland protection policy to prevent overheated real estate swallowing farmland in China,the urban expansion rate slowed down during 1992-2000.Beijing City has the fastest expansion rate after 2000 as a result of global economy development,Beijing urban planning and the Olympic Games in 2008.Urban land area per person has been gradually rising since 1956.Beijing City grew with relative high-density compact mode before 1984.But urban expansion indicates low-density sprawl trends after 1984,especially with "pie-like" form along the 5th and the 6th ring roads.The process of urban expansion shows the significant events,population growth and economic development are the most driving factors,in which the significant event is more prominent one.Highway construction and relative low land price in urban fringe area are the most important factors to accelerate urban low-density sprawl.

Soil erosion risk assessment is crucial to soil and water conservation monitoring,harnessing and so on.With the increase of national attention on the ecological environment and the development of science of soil and water conservation,research of soil erosion risk assessment is becoming more and more important.By consulting the published researches on soil erosion risk assessment,an improved method of soil erosion risk assessment was adopted in this paper.Firstly,distribution of soil erosion degree by various impact factors including altitude,gradient,land use type and soil types were calculated by GIS and statistic analysis.Secondly,integrative index of different soil erosion degree by impact factors were computed.Then the soil erosion risks by different impact factors for every subbasin were calculated by weighting impact factors corresponding to each degree of integrative index of soil erosion.Thirdly,soil erosion risk by every impact factor was classified into three levels and the corresponding maps were finished.The integrative degree of soil erosion risk also was classified by cluster analysis.Finally,comparing distribution of different soil erosion intensity with the distribution of soil erosion risk,the studied area was regionalized with various soil and water conservation aims.The results were that:(1) the method was reasonable and suitable for actual conditions,and it avoided subjectivity in weight decision.(2) The relationship between soil erosion and impact factors in Anxi County,Fujian Province were discussed.The intensity of soil erosion in <500m altitude zone,3～15°gradient zone,dry land and other wood land,acid skeleton soil and acid stone soil was greater than other grades of corresponding impact factors.(3) According the spatial distribution of soil erosion risk,the possibility of erosion of every subbasin and different effect of impact factors were clearly showed.The distribution of soil erosion risk and intensity of soil erosion are basically in accordance.(4) By comparing consistent and discrepancy of the distribution of soil erosion risk and intensity of soil erosion,zoning of soil and water conservation areas was more pertinent.Preventing and treating areas,controlling areas,preventing areas and reserve areas were confirmed and characterized so as to provide scientific basis for departments of water conservancy and agriculture which could make scientific and reasonable decisions and take some effective countermeasures for soil erosion controlling.

我国著名的地理学家、地球信息科学一代宗师、遥感应用、地理信息系统、现代地图学的开创者、当代地学界的翘楚!敬爱的陈述彭院士离开我们已经整整一个年头了!他那勇于探索,不断创新的学术思想;他那追求真理、严谨治学的科学态度;他那不畏困难、敢担风险的开拓精神;他那诲人不倦、培植新生的高尚情操,为我们这一代树立了光辉的典范!他的科学思维和辉煌历程,标志着新中国60年地球信息科学的发展史,为我国创建地学强国作出系统的贡献!半个世纪的师徒情谊,时刻缭绕在我的脑海里,我是在1956年师从述彭师的,当时我被分配在中国科学院地理研究所(在南京),开始安排我担任所业务秘书,我觉得年轻人到科学院还是多学点专业为好。

APDM is the pipeline data model based on Geodatabase technology issued by ESRI.The latest version is 4.0.In the entire pipeline integrity management system,APDM can effectively store and manage pipeline data. To successfully implement the digital pipeline's integrity management,the work of model maintenance and management is most important.There are two key problems in the management of APDM model,constructing and extending of the model.Before building pipeline Geodatabase,pipeline companies must construct APDM model according to their actual needs,which is model constructing work.When needs change,a mechanism is provided to ensure model modifying and extending.Considering the features of APDM model,this study proposes an XML-based method to realize the constructing and extending.First,the design principles,characteristics,history and conceptual model of APDM model are introduced,then detail descriptions on how the XML-based method works are provided, and its advantages are discussed.At last the APDM model management system is designed and implemented by visual studio.NET 2005 and ArcGIS Engine interface.By APDM model management system,people can quickly build and modify APDM model in visual user-interface provided by the system.The solution is proved feasible with a case study.

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.

The landscape spatial patterns of land use were a long-term result of interaction between human beings and nature.The coastal zone of western Pearl River Estuary,which is one of the hot spots of socio-economic development in China,was taken as the study area in this paper.The land use maps for 1995,2000 and 2003 were obtained by the interpretation of remote sensing images.The changes of land use information were analyzed.The result shows,main changes were that the cultivated land decreased and forest,construction land,water areas increased to different degrees.Under the support of GIS,the landscape spatial patterns of land use in study area were also quantitatively analyzed by using landscape indices such as fractal dimension,isolation index,fragmentation index,and diversity index.Result shows that the four landscape indices increased from 1995 to 2003 because of strong human interventions.At last the paper investigated the driving mechanism of the changes and concluded that population growth,pursuing for more economy benefits,effects of government policies,and its location advantages were the four main driving forces.

Virtual geographic environments(VGEs),which as the opposite of the real environments are the reflection of real environments in mental scene.It is not just a framework which emphasizing data sharing in GIS,and has become a knowledge sharing platform which emphasizing both database and model database simultaneously.As a research platform for earth system science,VGEs are oriented to geographic investigation and analysis of multi-domains.It is a very meaningful tool for geographic modelling,simulation and geographic problem solving.The world of today heavily relies on spatial data to manage the natural and built environments,also to construct VGEs.In this paper,the characteristics of mutli-sourced heterogeneous spatial data in VGEs were discussed,and heterogeneity in spatial data can be divided into five types,namely data values,schema,data model,syntactic and semantic heterogeneity.A Data Representation Model oriented to VGEs(DRM) which provides a common data model to define a data representation structure for traditional data and spatial data was designed in this paper.The DRM not only provides a clear description of geographic data,but also defines the relationships between geographic data.The processes and framework of mutli-sourced heterogeneous spatial data integration were proposed based on the above discusses.The integration consists of the following subparts: geographic data parsing,interaction between geo-data and geographic model,and geographic model parsing,running and results output.Also,spatial data parsing and the communion between mutli-sourced heterogeneous spatial data and geographic model were discussed especially.Lastly,the platform system of multi-sourced heterogeneous spatial data integration was designed and developed under the VS.NET2005 development environment combined with XML technology,and it can solve the bottleneck problems arise in geographic information resources which under heterogeneous environment.Some experiments were designed and discussed,and the results show that the platform we developed can be integrate multi-sourced heterogeneous spatial data effectively and can work better than other similar platform systems.

父亲离开我们将近一周年了,但是,我总觉得父亲依然还生活在我们身边。他慈祥的笑容,谆谆教诲、永远铭记在我的脑海中。我愿永恒记住1920年2月28日父亲的诞辰日,不愿想起2008年11月25日父亲的去世日,但事实告诉我们,这两个日子都必须记住,更要牢记的是这两个时辰之间,父亲留给我们难忘的一切。看着父亲的照片,他和蔼的身影一幕幕地展现在我的眼前,回想起与父亲一起工作,一起生活的时刻,几次提笔却又放下,眼泪不停地往下掉,湿透了桌上层层的稿纸,……。自我的母亲去世后,为了照顾父亲,我搬回了中关村家中,与父亲同住在一起,和谐的工作、生活。父亲的一生,给我们留下难以忘怀,永远值得铭记的精神财富。

Spatial interpolation of average 10-day air temperatures were conducted at the scale of 1km×1km in Heilongjiang Province with CoKriging method through data exploring,error fitting,accuracy evaluating and model comparing.In this course,ground elevation and aspect data that are the local factors bringing on the spatial variation of air temperature were used to consider the autocorrelation of 10-day period air temperature and its relation to them,adopting 10 years of average 10-day air temperature data of 80 weather stations from 1997 to 2006 as interpolation variables.Cross-validation results show that the averages of mean,root-mean-square,average standard,mean standardized and root-mean-standardized errors are 0.0024℃,0.774℃,0.682℃,0.0006 and 1.124 respectively.According to the principle of geostatistics,this interpolation accuracy can meet the demand of climate change research all over the province in a macro level.On the basis of 10-day surface air temperature,average monthly and yearly surface air temperature have been work out.By the use of interpolation and calculation data of average 10-day air temperature and all data from weather stations as data source,spatiotemporal variation characteristics of average 10-day period,monthly and yearly air temperature have been analyzed to show that their spatial variation of air temperature in the Southeast are less than in other regions and,temporal variation of 11-13th,12-14th and 19-21st 10-day period are a smooth downward trend,15-17th,26-28th and 27-29th 10-day period are steadily rising trend,average air temperature in July are slightly downward trend,a slight upward trend in September and November,and about 1℃ higher between 5-9 months.The mean value of average annual air temperature is 2.9 ℃ fluctuating between 2.5-3.3 ℃ and being a little rising but no obvious trend.Change ratio of some average 10-day air temperature become lower and stable between spring and summer,higher between summer and autumn,indicating the shift of boundary among seasons.All of the air temperature data attained above by interpolation and calculation can be put into a geodatabase by which spatiotemporal variation of air temperature has been analyzed in order to lay a foundation to air temperature change monitoring,land capability evaluation,agricultural regionalization and crop yield estimation for related research in the future.

DEMs and the terrain features derivation accuracy are usually affected by many factors such as sample points density and distribution,DEM form structure and interpolation methods.Since only the elevation of the sample point can be obtained,interpolation will be used to estimate the simulative value of the other points.In this study,four interpolation methods,IDW interpolation,Spline interpolation,Kriging interpolation and TIN interpolation, are evaluated on a Gauss synthesized surface with peak and valley just similar as a real surface,by comparison with the true values of gradient and aspect.Interpolation result is more sensitive to the errors when gradient is less.The uncertainty of gradient,in the four methods,is the least for SPLINE interpolation,and increases in turn of KRIGING,IDW,and TIN interpolations.And the uncertainty of aspect in the four methods,as that of gradient, is the least for SPLINE interpolation,and increases in turn of KRIGING,TIN,and IDW interpolations.The results provide information for the selection of interpolation algorithms.

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.

There happened a scale of 8 on the Richter calculations earthquake in Wenchuan County,Sichuan Province on May 12th of 2008.It caused a lot of landslides in Beichuan County and many landslide-dammed lakes had been formed,some of the lakes are at very urgent risk of dam breaking and would threaten downstream people.Results of an investigation on landslide-dammed lakes are analyzed after Wenchuan earthquake using various types of remote sensing data including aerial,visual,and SAR satellite data.This paper discusses the general role of distribution and variation of landslide-dammed lakes.The dynamics of the Tangjiashan landslide-dammed Lake,which is the largest one,is analyzed in detail.Area changes of the Tangjiashan landslide-dammed lake in different periods,including the course length and the water surface area of inundated region are obtained from images between May 14th and 26th.The course length and the water surface area were about 7.39km and 1.14 km² on 14th May,respectively.By 26th May,the course length and the water surface area reached 17.6km and 4.09km²,respectively.The results provided basic information for disaster reduction of the landslide-dammed lakes in this region.

Geo-ontology is the key of geographic knowledge existed in human brain being rebuilt in computer.The geo-ontology has important significance to improve and support formalized expression of geographic knowledge in computer.The model of spatio-temporal geo-ontology is a set of specification of formalized instruction describing geographic spatio-temporal characteristics.And it is the reference and basis for building spatio-temporal geo-ontology.The framework of spatio-temporal geo-ontology model based Geography Markup Language(GML) and the theory of spatio-temporal reasoning is proposed.The method of building spatio-temporal geo-ontology model is studied.The spatial ontology model,which consists of feature model,geometry model and spatial relationship model,is implemented by OWL language.And the temporal model,which consists of time instant and time period,is illustrated as well.The feature model is the core of spatio-temporal geo-ontology;it is connected with geometry model,temporal model,and spatial relationship model by object property in OWL.An applied example"the ontology of administrative regionalization"is given based on the model in the end.In the section,region ontology based Class Feature in spatio-temporal geo-ontology is built and it can be the ancestor of all other kinds of geographic unit.Administrative region ontology inherits the region ontology and extends it.The spatio-temporal characteristics and administrative level characteristics of administrative region are demonstrated based on some object properties defined in the model of spatio-temporal geo-ontology.It is of instructive significance to build and share the instances of geo-ontology for different applied studies based on the model of geographic spatio-temporal ontology.

Semi-empirical models are the main models to retrieve chlorophyll-a concentration in remote sensing.The water is so turbid and eutrophic in Taihu Lake that the accuracy of some semi-empirical models varies highly.The datasets were collected over a considerable range of optical properties,trophic status,and geographical locations in Taihu Lake.So,it is very useful to find a model which can retrieve chlorophyll-a concentration in a good accuracy and has the best ability to adapt time changing.This study applied a recently developed model of the form 1/Rrs(λ1)-1/Rrs(λ2)×Rrs(λ3) where Rrs(λi) is the remote-sensing reflectance at the wavelength λi.The objectives of this paper are(a) to build the reflectance first-derivative model、reflectance ratio model and three-band model using the data measured from June to October in 2005 to find which model is the best,(b) to find out the special bands which are suitable in Taihu Lake for the three-band model,and(c) to examine these three models by the dataset measured in November in 2006 and 2007.Strong linear relationships were established between analytically measured chlorophyll-a concentration and both the three-band model 1/Rrs(λ666)-1/Rrs(λ693)×Rrs(λ734) and the two-band model R(λ705)/R(λ680).Accuracy for all these models were measured by R2 and RMSE.The result is that the three-band model is the best one of them.Its normal RMSE is less than 20% of the change which was shown in the dataset.And it has the best ability to adapt time changing that the normal RMSE of 2006 and 2007 is 11.17 and 9.74 respectively.We can also find that the bands used in the three-band model are available from some satellites.So,the three-band model has a good future to retrieve chlorophyll-a concentrations.

Geomorphologic classification system is essential to geomorphologic research and mapping.Using the compiling methodology and standard of geomorphologic maps with a scale of 1∶ 1 000 000 in 1980's in China,based on the summarization of geomorphology,classification research at home and abroad,and the technology such as remote sensing image,digital elevation model(DEM) and computer automated cartography and so on,this research concludes and summarizes the principles followed in the classification process of digital geomorphology;analyzes the mutual relations hips among them;discusses various indexes of digital land geomorphologic classification: including morphology,genesis,material composition,age etc.The classification system puts forward numerical classification methodology of 3 classes,6 grades and 7 layers of digital Land geomorphology in China;presents data organization method of digital geomorphology,that is: morphology and genesis types represented by polygon map spot,morphology and structure type represented by point,line and polygon map spot together.Moreover,the article specifically presents the geomorphologic types of different layer and different level of various genesis types.The research of classification system of digital geomorphology provides a basis for the interpretation and cartography of Land geomorphology based on multi-source data such as remote sensing etc.

DEM data error is different from DEM's terrain representation error.This paper focuses on the relationship among DEM data error,terrain representation error and slope accuracy based on high resolution and high accuracy DEM.The result shows that(1)data error reduces with the increase of the cell size,while terrain representation error rises rapidly;(2)slope error firstly reduces and then increases.The lowest point of slope error's trend is an important point.At this point,the corresponding cell size is the most suitable cell size of DEM.The cell size is not only related to the DEM data error,but also closely related to the terrain complexity.This paper makes them clear about the source and characteristics of slope error derived from DEM.