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  • 2006 Volume 8 Issue 2
    Published: 25 June 2006
      

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  • ARTICLES
    CHEN Shupeng, LU Feng
    2006, 8(2): 1-5.
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    Metropolitan region, which symbolizes the human civilization, is gradually formed by the long-term interactions of both natural and social factors. Especially in China, development of metropolitan regions has become one of the most significant strategies for its future regional planning. Moreover, it is believed that the latest trend for regional development should be spatial structure adjustment in order to increase the economic benefits, as global economy competition becomes even more striking than ever before. Currently, lots of metropolitan regions on our backland successively form and grow; the number of which almost comes to 30, including the three well-known entities, i.e., the Yangtze River Delta metropolitan region, the Pearl River Delta metropolitan region and the Beijing -Tianjin -Hebei metropolitan region. However, those experiences from worldwide metropolitan regional development show that it will be a natural principle that large amount of people and investment pour into super port-cities and bring through non-equilibrium of regional economic growth and dependence on the coastal areas. Therefore the planning and development of metropolitan regions should observe such a principle of social and economic development. The formation of metropolitan regions goes through long time history accumulation. When it was in agricultural times, these regions were inner ports containing large population and dense river networks. When it was in industrial times, they were outer ports connecting the world. When in current information times, they are developing towards modern airports and information ports. Only all sorts of ports integrated can they possess the whole functions of world-class free ports. It is the ultimate goal of regional economic development. From the view of the geo-economy, the metropolitan regions generally have obvious regional economic superiority and leading effect of the financial center, ahd occupy absolute proportion of GDP. Along with the unceasing expansion of commuter circles and capturing of the continental heartland, the metropolitan regions have broken the spatial -temporal distribution pattern of the administrative divisions, impelled the regional economic reorganization and promoted it to develop towards the transnational economy. The development of metropolitan regions is of extreme imbalance and each has its own characteristics, but generally exhibits similar development phases and regularities in regional heterogeneous pattern. Of the three big metropolitan regions, analyzed from the geographical location, the Beijing-Tianjin-Hebei metropolitan region has the humanities superiority; the Pearl River Delta region which adjoins the international metropolis Hong Kong, has the location superiority in Asia; and the Yangtze River Delta region has the potential of "butterfly effect", which unfolds the global charm to attract the whole world. Interior cities within the metropolitan regions also compete for key city intensely with each other. Since the differences in economic development level, development opportunity, location superiority and human factor exist, in order to enhance the metropolitan regional cohesive force and competitive power, overall planning should be made and different measures should be identified under the guidance of scientific development concept of mutual supplement of each city and surmounting their respective obstacles in the process of development. Dynamic monitoring with high-resolution satellite remotely sensed images reveals that these metropolitan regions have some common fault such as heat island effect, inversion layer air pollution, groundwater funnel, land subsidence, sea water invasion and green space insufficiency. In addition, researches indicated that these regions are extremely weak on emergency reaction. Considering the strong mutual dependence of industrial structure and the production process inside the metropolitan regions, in the planning and developing process of metropolitan regions, it should be kept in mind that early warning mechanism and emergency solutions should be established aiming at the serious environmental situation, and guaranteeing the sustainable development of metropolitan regions.
  • ARTICLES
    CHAI Huixia, CHENG Weiming, QIAO Yuliang
    2006, 8(2): 6-13.
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    Loess geomorphology in China belongs to one of the typical landforms, whose classification system is the foundation of mapping. Up to now, the national classification system of loess geomorphology has not yet been established and published. By adopting new classification principles such as morphogenetic, geological tectonics and delamination, based on every kind of geomorphologic classification projects, this paper analyzed the nationwide research of loess landforms, with the advanced techniques such as Remote Sensing, Geographical Information System, established new national loess geomorphologic classification system, and put forward 5-bit number for coding the loess geomorphologic data. Based on Remote Sensing Image (Landsat TM and ETM), the characteristic atlas of typical loess geomorphology was compiled. The classification system includes fiver layers: relief and height, genetic types, position and outward appearance, slope-ditch density-incision depth, by integrating morphology with genesis. This research established the solid foundation for use the inside high-resolution satellite Remote Sensing data to complete 1:1 000 000 loess geomorphologic map of China. This classification system can adequately reflect the types characteristic of loess geomorphology and can also keep consistency with classification system of national digital landform, the classification system possesses the expandability function of other types.
  • ARTICLES
    ZHANG Lili, ZHU Jiang, ZENG Zhiming, CAO Guofeng
    2006, 8(2): 14-16,29.
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    Analysis of automatically extracting terrain features based on Digital Elevation Model (DEM) such as slope gradient, slope aspect, curvature, flow paths and delineate drainage networks, is always a kind of fundamental work for many geoscientists. Shuttle Radar Topography Mission (SRTM), which produced a near global scope database of high accuracy elevation data, offers an opportunity to extend terrain analysis from local to global. However, it is a major disincentive for geoscientist to deal with massive DEM data even in a limited interesting research area. Grid Services for Elevation Derivatives (GSED) is proposed for spatial data dissemination and continental-scale topographic analysis computation based on DEM. The architecture of GSED is presented in the paper and unique problems that appear in the computing test are elaborated. Automation topographic factor extraction from SRTM is carried out through GSED. Traditional sequential algorithm has been reorganized to adapt to the distributed computing environment. Tibetan Plateau is selected as the focus area, and preliminary result is established for comparison with GTOP030. The result confirms that GSED is an effective method to solve the problem of high throughput computation with large scale geographic data.
  • ARTICLES
    ZHANG Zhifeng, WANG Lihua, SHI Aijun, LI Jianjun, TAO Lei, DONG Lei
    2006, 8(2): 17-23.
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    Landscape mosaic structure mainly refers to the distribution of patches, which are different in size and shape in space owing to the interaction of various ecological activities. The study on landscape mosaic structure provides valuable information for rationale management of the environmental resources and has been one of the key study areas in landscape ecology as a whole. This article firstly presents the dynamic change of land-use/land cover landscape in the last 6 years in Widgeon Lake wetland based on RS,GIS and GPS and discusses its environmental effect on wetland. And then based upon which, through selecting indices such as patch size, fractal dimension, fragmentation, diversity and dominance index, etc., it gives a detailed analysis of the change of wetland resources landscape mosaic structure in the last 4 years, supported by RS image with high spatial resolution. Widgeon wetland located in the range of 115°47′-115°54′E and 40°25′-40°30′N covers an area of 10000 hm2. Satellite imageries of different years, Landsat TM in 1996, Landsat ETM in 2002, Indian IRS in 2000 and 1:30 000 infrared color aerial photograph in 2001 were used to analyze the dynamic change of land use/land cover landscape and wetland landscape mosaic structure in this study area. For the images captured approximately in the same season, the change detection error introduced by mere seasonal difference was minimized. Following the interactive interpretation procedure, the distribution map of land use/land cover landscape in 1996 and 2002 and wetland landscape in 1998, 2000 and 2002 were obtained, which were geometrically registered to a common map projection. Software Arc View 3.3, MiragePro5.5 , PCI 8.2 and Excel 2000 were employed in the work. The study shows that the number of wetland resources patches in 2002 decreased by 48.5% compared with that in 1998, the index of the fractal dimension of the whole wetland landscape patches decreased from 1.464 in 1998 to 1.426 in 2002 and the index of fragmentation decreased from 0.9979 to 0.9959. In short, the impact of human activity on the Widgeon Lake wetland during 1998-2002 was not most important because some protective measures had been taken after the nature protected area was built up in 1997. The impact of drought on the wetland was the fundamental factor, especially from 1998 to 2002, but great attention should be paid to the impact of human activity.
  • ARTICLES
    YAO Min, ZHONG Ershun, FANG Li
    2006, 8(2): 24-29.
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    The problems of how to manage the land and resources spatial data are presented based on the analyses of their characteristics. The land and resources spatial data are characterized by multi-sources, multiscales, multi-dimensions, multi-times, etc. The application of spatial database technique is the precondition of integrative management of land and resources spatial data. Multi-sources land and resources spatial data can be managed by converting them to the same format or can be accessed directly. In order to reduce the conversion error, metadata can be used while the land and resources spatial data be converted from one format to another. Multi-scales land and resources spatial data can be managed by metadata driving technique because the content of metadata includes the information of scale and projection. For historical spatial data, the paper gives the method of time sequence storage, when the parcels changed, they would be stored in the historical spatial database. All the changed parcels can be traced to their original state. Only by solving the above problems, can the integrative management of land and resources spatial data be realized.
  • ARTICLES
    LIN Hui, ZHANG Jie, YANG Ping, LIU Jia
    2006, 8(2): 30-37.
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    Two basic dimensions for describing the human social development and human cultural phenomena are space and time. Previous humanities research emphasizes much of the attribution of phenomena itself and time dimension because of the technologic limitation and epistemological difference. Sometimes these research ignored the space dimension or retained the attitude of excluding it. Fortunately, more and more scholars have rethought the importance of spatial coordination system and begun to use spatial thinking in their research. These scholars come from the discipline of history, philosophy, literature, economics, sociology, anthropology, archeology, geography, politics, statistics, etc. This article, based on the instructive thought of space and integrated humanities and social science research, intends to take modern geographic information science and methodology and related space technology as a platform, to tentatively discuss the spatio -temporal characteristics of multi-disciplinary humanity and social science research. Emphases are given particularly to the spatial attribute, space distribution, spatially mutual affection and space evolution rule of the economic and cultural phenomena in human society. In this article, the authors put forward the elementary thought of spatially integrated humanities and social science research which includes basic concept, research object, basic methodology and development direction and wish it can promote the discussion.
  • ARTICLES
    ZHANG Xiaodong
    2006, 8(2): 38-39.
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    This article analyses the disadvantage of traditional historical geography as the rapid development of GIS provides an opportunity for historical geography, describes the achievements, existing problems and tendency of the applications of GIS in historical geography and presents several ways for better combining historical geography with GIS.
  • ARTICLES
    LIN Ting , LIU Renyi, LIU Nan
    2006, 8(2): 40-45,2.
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    Workflow management is a new research area and is known as "logistics" of information systems. It can arrange suitable people or software to perform right tasks at right time and automate business process. According to the requirement of Land Use Planning Geographic Information System (LPGIS), based on the referenced model which is called Workflow Management System (WfMS) and with the support of technology of ArcObjects and SQL-Server, this study overcomes a series of difficulties, brings out the general framework of the system and gives an example relating to the applications.
  • ARTICLES
    WU Hongzhi, ZHANG Baiping, XU Juan, XIAO Fei, ZHU Yunhai
    2006, 8(2): 46-48.
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    Although Mountain Altitudinal Belt Spectra Information System (1.0) has succeeded in digital integration of mountain altitudinal belt spectra, it has still deficiencies to be improved and perfected, including occasionally label illegibility, unchangeable color arrangement of altitudinal belts, dissatisfactory display of a great number of mountain altitudinal belt spectra. This paper explores the technical improvement and perfection of Mountain Altitudinal Belts Information System 1.0 (MABIS 1.0), mainly in spatial visualization of mountain altitudinal belts spectra, including the brief design process, spatial data labels, page rolling, color customization, operable data axes, etc.The result shows that perfection of spatial visualization in MABIS can not only efficiently manage the mountain altitudinal belts spectra, but can also facilitate visualizing the selected mountain altitudinal belts spectra data expediently and directly, discovering the spatial distribution pattern of mountain altitudinal belts of interest. This also lays a solid foundation for developing the World Mountain Altitudinal Belts Information System (MABIS).
  • ARTICLES
    CHEN Jianjie, YE Zhixuan, KE Zhengyi
    2006, 8(2): 49-53.
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    In order to integrate existing land information and realize land information exchange and sharing,the key task at present is to build land & resources clearinghouse. Taking land register as an example, this paper explored the domain knowledge expression of register and requestor of web services based on the ontology technology, realized the retrieval, matching and learning of web services by combining OWL-S Ontology description language with WSDL and resolved the UDDI semantic description and discovery for land information. It also put forward a land information web services frame based on ontology and an elementary process.
  • ARTICLES
    ZHENG Zhigang, PENG Wanglu, JIN Chuanyang
    2006, 8(2): 54-58.
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    In this paper, a new approach based on combining two radically different texture features is proposed for similarity retrieval of multi-source remote sensing database. One takes a statistical approach in the form of gray level co-occurrence matrix (GLCM), the other takes a signal processing approach with tree-structured wavelet transform or wavelet packets. Particularly, we also combine texture feature with spatial relation in the statistical method. The similarity retrieval contains six consecutive stages: preprocessing the images in the multisource remote sensing database, feature extraction, feature sequence normalization, weights for feature elements, similarity measure, and experimental evaluation. Through comparison with other methods: such as the gray level co-occurrence matrix, the tree-structured wavelet transform or wavelet packets, in combination GLCM with special relation, the proposed method shows good tradeoff between retrieval effectiveness and efficiency. The experimental results indicated that the combined texture retrieval way has powerful practical merits.
  • ARTICLES
    YE Yu, LIU Gaohuan, FENG Xianfeng
    2006, 8(2): 59-65.
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    Spatial distribution of population is a key content of "Digital Earth". On the basis of essential theories of population distribution, the authors review the progress of research on spatial distribution of population based on GIS and RS from five aspects: 1) factors influencing population distribution and relationships among them; 2) application of spatial data, such as land use infrastructure; 3) indirect population index; 4) modeling of the spatial distribution of population; and 5) spatial distribution of urban population. Finally, under the support of grid data model, this paper applied Remote Sensing data, terrain data, traffic data, river data, resident data, and socio-economic statistics to calculate the spatial distribution of population in Fujian province at township level.
  • ARTICLES
    JIANG Yan, ZHANG Shanghong, ZHAO Dengfeng
    2006, 8(2): 66-70.
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    VR-GIS is a kind of new technology which integrates the characteristics of virtual reality with GIS. Digital flood control system of city based on VR-GIS is playing an important role in decision-making. In light of the 3D-system development of flood control in Harbin, this paper discussed some key problems about digital flood control system developed with VR-GIS, including 3D scene construction, database construction, flood simulation, etc., which provided a research platform for digital flood control system.
  • ARTICLES
    TANG Wei, CHEN Suozhong, ZHU Ying, SUN Yaqin
    2006, 8(2): 71-76.
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    Many challenges are associated with the integration of geographic information systems(GIS) in terms of specific model applications.One of them is to adapt models to the environment of GIS. The unique aspects of water resource model require a special approach to the development of GIS data structures. The expanded development of GIS applications for handling water resources management analysis can be assisted by use of an object-oriented approach.In this paper, a conceptual GIS data model is formulated to integrate the modeling problem into an operational framework, based on which, extended GIS functions are developed to implement a tight linkage between the GIS and the groundwater model. Through the object-oriented approach, data, models and users interfaces are integrated in the GIS environment, creating great flexibility for modeling and analysis.
  • ARTICLES
    CHEN Suozhong, LU Guonian, ZHU Ying, YANG Chunxia
    2006, 8(2): 77-83.
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    In this paper, the parameters of groundwater flow numerical simulation are divided into three types, namely, point spatial distribution, linear spatial distribution and planar spatial distribution, according to the parameter spatial distribution characteristics. Using spatial analysis function of GIS, the technological course that the parameters are automatically extracted is studied. By the topologic analysis of the spatial position relation of point, line and polygon, the spatial position relation of groundwater mining well, monitoring well of groundwater level dynamics linear and planar surface water system, boundary of simulation area, distribution subdivision of planar parameter and model spatial separated grid are confirmed. The parameters of groundwater flow simulation can be automatically acquired by transforming vector data into raster data mutually. Combining with the data file structure of parameters in the groundwater flow finite-difference numerical simulation, the data files of raster structure extracted by GIS are automatically transformed into the data files of model parameter file structure, and the aims that the model parameter files are automatically organized and the efficiency of groundwater flow numerical value simulation is improved are achieved.
  • ARTICLES
    MING Dongping, LUO Jiancheng, ZHOU Chenghu, SEHN Zhanfeng, LI Junli, SEHNG Hao
    2006, 8(2): 84-90.
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    With the developments in satellite sensor technology, data acquisition technology developed rapidly; and with the start of a series of space-based observation network for Earth science, such as EOS, GTOS, ECOS, GOOS etc., high performance processing and analysis of tremendous data becomes the bottleneck faced by us. According to the shape differences between different data carriers of terrene, ocean and atmosphere, this paper divides spatial data into four classes: terrestrial-solid based spatial data, terrestrial-liquid based spatial data, marine-floating based spatial data and atmospheric-floating based spatial data. Then this paper introduces the concept of the basic unit and proposes their actually existing style in the four types of spatial data mentioned above. Furthermore, this paper simply reviews geocomputation and expands it to geo-spatial computation. Then this paper discusses the connotation and classification of geo-spatial computation and summarizes the general computing procedure: data →features→knowledge. According to the differences of the computational behavior and the computing emphasis, this paper divides geo-spatial computation into two classes: deep-computation and proactive-computation. Consequently, this paper explains the computing pattern of deep-computation and proactive-computation. What's more, a case study of information extraction and target recognition from remote sensing image based features was done to illustrate and testify the ideas mentioned above. Finally, this paper summarizes the relative problems about spatial data computation and expects the direction of future researches.
  • ARTICLES
    LI Guobin, WU Fadong, ZHAO Jurunei
    2006, 8(2): 91-94.
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    Spatial-Temporal GIS is an important branch of GIS, which, in other words, is an inevitable tendency to realize dynamic digital earth with the essential technology. The technology of static 3D GIS is already well developed, but 4D GIS, i.e., traditional GIS plus temporal dimension, is still under the stage of theoretical study because its essential technology involves creation and manipulation of the temporal data base, which are related to temporal data base modeling, mainly dealing with storage and research of mass data. In this paper, it is a reasonable TGIS data modeling to combine simple and feasible snapshort modeling with convenient flexible object-oriented data modeling, while avoiding the consistent and redundant snapshort modeling and complex object-oriented data modeling. The paper adopts a special way in dealing with the attribute of time, which firstly creates a fundamental data, then produces buffer data through snapshot data modeling, finally forms a new data pool with time stab. By so doing a plenty of space is saved in data storage and it is easier to realize calculation of data, which is to divide store layers based on the varying objects. The theoretical approach efficiently settles the "bottleneck" of TGIS and has been substantiated through Automatic Cellar Theory.
  • ARTICLES
    WU Tong, NI Shaoxiang, LI Yunmei, ZHOU Xinxin
    2006, 8(2): 95-100.
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    Outbreaks of the Oriental migratory locust, Locusta migratoria manilensis (Meyen)have once again become a serious problem in the last two decades of the 20th century in China. One of the coastal breeding areas of the locust, Huanghua city in Hebei province was chosen as a study area in this paper. LAI of different kinds of vegetations in the study area have been derived from the gap fraction of vegetation canopy. From the point of view of the mechanism of developing the optical models and quantitative analysis, four algorithms used for LAI retrieval based on the gap fraction of vegetation canopy were analyzed and compared. The result shows that the LAI-2000 algorithm is the best one in terms of the accuracy of LAI retrieval among them. For verifying the conclusion, a fitting between canopy closure and the LAI retrieved from four algorithms were made. It is found that a positive correlation exists between the retrieved LAI and the canopy closure for all the three kinds of vegetations. In addition, a negative correlation exists between the LAI and the area where the locust outbreaks appeared. In other words, with the decrease of the LAI, the locust outbreak affected area appeared a linear increase. These findings laid the scientific foundation for quick monitoring the dynamics of locust populations in real time and at large scale and efficient control of locust plague.
  • ARTICLES
    ZHU Jiang, ZHANG Lili, ZENG Zhiming, ZHONG Ershun
    2006, 8(2): 101-105.
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    Conventional Web GIS has partially solved the problems of disseminating spatial data via Internet. However, few systems have the powerful capability to offer the high throughput and compute intensity of Largescale Geo-imagery Service. With the aid of geospatial information collecting technologies such as GPS and Remote Sensing, the real-time spatial data can be made available. Many organizations have built multi-scale heterogeneous massive spatial database of different levels containing high-resolution aerial, satellite, and topographic data. A cost-effective solution clustering multi low-cost commodity-class PCs is proposed, which has the characteristics of high-scalability, high-availability, easy-manageability and cost-effectiveness. This paper introduces the architecture of Large-scale Geo-imagery Service using cluster technology and describes the core component called load balancer, which chooses one of the four different load balancing algorithms to adapt to the physically deployed systems. Based on the self-adapted dynamic load balancing model, an agent-based feedback mechanism was developed to monitor service nodes' instant state and arbitrate which should serve the next coming request. We compared four inner approaches: round-robin scheduling, weighted performance scheduling, weighted least-load scheduling, and domain divided scheduling and found that domain divided scheduling method can improve performance dramatically for its high hit ratio cache.
  • ARTICLES
    LIN Lin, HUANG Sixun DU Huadong
    2006, 8(2): 106-109.
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    Cloudtop properties constitute one of the important cloud properties. Cloudtop properties include cloudtop pressure, cloudtop temperature and cloud effective emissivity. One of the greatest current uncertainties in Global Climate Models is the role of clouds. The CO2 slicing algorithm is one of the important methods for retrieval of cloudtop properties. It is founded based on the difference in atmospheric absorptions due to CO2 between two spectrally neighboring channels in the wings of CO2 absorption band with a resolution of 1km. This technique has been applied to HIRS data for about 20 years. Since Earth Observing System (EOS) platform launched in December 1999, the Moderate Resolution Imaging Spectroradiometer(MODIS) has been the first sensor to have CO2 slicing bands at high spatial resolution. This paper mainly describes the theoretical model of CO2 slicing and it' s applications. An analysis of the characteristics of the method and the estimate of errors will also be discussed. Finally, research issues are recommended for future studies.
  • ARTICLES
    HE Liming, WANG Qiao, LI Xiaowen, YAN Guangjian, WANG Wenjie, WEI Bin
    2006, 8(2): 110-115,136.
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    Several atmospheric correction methods were summarized firstly. These methods are dark object subtraction method, histogram matching method, empirical line method, soil line method, invariant-object method, cloud-shadow method, vegetation index related method, contrast reduction method, step function method, clustering matching method etc. These methods are related to aerosol retrieval methods, substantially. Then several atmospheric correction softwares or modules were introduced, which include ATREM (The Atmospheric Removal Program), HATCH (The high accuracy atmospheric correction for hyperspectral data), EXACT (Exact Atmospheric Correction Technique), ATCOR(Atmospheric and Topographic Correction Model), SMAC (Simplified Method for the Atmospheric Correction), FLAASH (Fast Line-of-sight Atmospheric Analysis of Spectral Hypercubes), ACORN(Atmospheric CORrection Now) etc. Sea color remote sensing, hyper spectral remote sensing, airborne remote sensing and multi-angular remote sensing have their particularities, their atmospheric correction methods are introduced, respectively. The problems and the way on how to improve the precision of atmospheric correction were also discussed.
  • ARTICLES
    JIAN Ji, LI Hongjian, DAI Xiaoai
    2006, 8(2): 116-119,143.
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    Qinghai Lake is the biggest salt lake in China, which is also a well-known wetland in the world. However, with the deterioration of the land desertification in the surroundings, desertification of the lake area also becomes aggravated. In this paper, the author firstly analyzed the basic natural, social and economic features of the study area to assess land desertification. Then the environmental background of land sandy desertification was specified. On this basis, the author, combining the content and scope of desertified land inventory with that of land desertification monitoring in Qinghai Lake, made an integrative assessment on land desertification in the lake area by adopting ASTER satellite image interpretation of the area; and classified the degree of land desertification and analyzed spatial distribution of land desertification by using the interpretation data.
  • ARTICLES
    LUO Jing, CUI Weihong, NIU Zhenguo
    2006, 8(2): 120-124.
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    The spectrum curves of different objects are the centralized embodiment of the objects reflecting to electromagnetic wave. The difference of spectrum curves are caused by many factors, we can differentiate the different object types according to the different spectrum curves. It is obvious that the spectrum reflects not only the status of the objects, but also the environment surrounding them. According to this, we took the changes of spatial and temporal features as the foci of our study, and made the best use of geographic Tupu theory which primarily expresses the spatio-temporal features of geographical phenomena, and of the conceptual expression to the rules in combination with the hyper-graph spatio-temporal conceptual model, as well as used the object-oriented technology to combine several factors affecting the growth of tobacco, constructed a model which satisfied the practical application requirement, and finally had the model used in monitoring the growth of the tobacco. Through practice, the model proved to be feasible in theoretical aspect and actual use.
  • ARTICLES
    LONG Yi, TANG Guoan, ZHOU Tong
    2006, 8(2): 125-130.
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    The analytic function of GIS and the cartographic function of Computer assisted cartography (CAC) are two aspects of geographic spatial data application. The conflict, which exists between GIS and CAC, comes from several different aspects including spatial positions, attributes and relations of geographical objects, and prevents their data from sharing. It usually makes geographic spatial data recollected and wasted. Beginning with a general method that thinks about data, software system and cartographic symbol database at the same time, this paper basically discusses the strategy and methods of geographic spatial data integration. The result of the research indicates that the traditional integration method based on assistant curve makes it more difficult to build and renew geographic database. In this paper, two main methods are put forward that consist of data integration based cartography and data integration based analysis. Compared with the cartographic style, the analytic style has some advantages, such as easily collecting, mapping and analyzing, simple spatial relation and integrated object entitles, so it is obviously more available for geographic analysis and cartography. The research on the strategies of geographic spatial data integration will help to syncretize GIS and CAC by combining artificial intelligence and expert system with data integration scheme.
  • ARTICLES
    ZHANG Yongmin, ZHOU Chenghu, ZHANG Yang
    2006, 8(2): 131-136.
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    With the rapid development of technologies in computer, digital image, geographical information system and relevant commercial softwares, great progress has been made in the field of automatic classification and mapping of regional landforms since the 1980s. However, two methods have been employed till now. One is visual interpretation using digital images, and the other is the automated extraction of landform characteristics from DEM. Because of the difference in personal visual perceptions, different boundary lines of the same landform unit often appear in two workers' interpretation results. Thus, the results obtained from the first method are difficult for future use. As to the second method, it is difficult to get detailed classifications (for example, to distinguish a valley plain from an open plain) by using DEM alone due to the complex nature in landform characteristics. In fact, DEM and digital image contain different, yet complementary, informations related to landform features. Therefore, a new method to integrate landform information of both DEM and TM image by digitizing signing lines in TM image is presented in this paper. With this approach, six types of basic landforms were successfully classified and mapped automatically in Guyuan county of Hebei province. In addition, the spatial variability of accuracy in classification was also evaluated by an application of fuzzy set theory using the notion of entropy in Guyuan case studies.
  • ARTICLES
    CHEN Zhiqiang, CHEN Jianfei
    2006, 8(2): 137-140.
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    ASTER image is one of the high spectrum resolution remote sensing images which could serve as new information resources of higher quality. NDBI is derived from the NDVI and is rewritten into the formula of NDBI=(ASTER4-ASTER2)/(ASTER4 + ASTER2). In this study, an ASTER image of Fuzhou City was used to extract the urban land-use information of the research area by NDBI method. The result was testified by comparing to the other two methods: PCA and Unsupervised Classification with the same ASTER image and Supervised Classification with the TM image. The result showed that The interpretation result by NDBI method is better than those by automatically classification method. The NDBI method not only has higher precision, but also can distinguish the old buildings from the new ones.