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  • 2002 Volume 4 Issue 4
    Published: 25 December 2002
      

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  • ARTICLES
    LIU Yaolin, JIAO Limin
    2002, 4(4): 1-6.
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    The paper probes the application of artificial neural network in basic land price evaluation after analyzing current methods of land evaluation and properties of artificial neural network. Two artificial neural network models for land evaluation are developed, which are called as the network model I and the network model Ⅱ. The network model I is based on the relation between general value of all factors which are taken into account in evaluation work and basic land price.The network model Ⅱ is based on the relation between the value of single factor and basic land price. The improved algorithm for back propagation of two kinds of models is presented. Taking Wuhan city as an example, the models developed in this paper are tested.After comparing different models, we can make conclusions as follows: 1.The training error of neural network model I is almost the same as the testing error of exponent model, which can reflect that the relation of general acting value of factors and basic land price is the exponent relation in the test area. 2.The training error of neural network model Ⅱ is relative smaller than that of exponent model, which shows the model can represent correctly the relation of acting factor and basic land price. The model do not need to decide the weight for each factor by the people and reduce the influence to the evaluation work by the people. 3.The result shows that the models of artificial neural network applied in land evaluation are objective and accurate.
  • ARTICLES
    SU Lihong, LI Xiaowen, LIANG Shunlin, WANG Jindi
    2002, 4(4): 7-15.
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    The paper puts forward data frame of the remote sensing knowledge base. Oriented-object method is adopted to organize data of the knowledge base. The typical land surface objects, which are classified into vegetation, soil, water, snow, minerals, man-made object, are the center to be used to link measured data at field, prior spatial data, expert system data, images and models.The knowledge base consists of five aspects: 1)The database for measured spectrum and relevant environmental factors.The database consists of 6 kinds of data.The first is the measured data, which are made up of canopy spectrum, soil physical-chemical data (N, P, K, humidity etc), plant bio-chemical data (chlorophyll, nitrogen etc), vegetation structure (LAI, LAD etc) and biomass data, component (leaf, stalk etc) spectrum data, and data about microclimate and weather. The second is the instrument information. The third is data of campaign site condition. The fourth is the documents about observation methods and measured data processing methods. The fifth is the documents about surveyors. And the sixth is the metadata.2)The spatial database for landform,land-use and land-cover etc.3)The expert system for vegetation seasonal changes and spatial patterns.4)The remote sensing image base, which are acquired by field, aerial and space approaches such as multi-angle, multi-temporal, multi-spatial resolution, multi-spectral resolution, multi-platform etc. And 5) the remote sensing physical model base. The knowledge base can not only retrieve spectrum and environmental factors of typical land surface objects, but also simulate the spectrum of remote sensing pixel when the measured spectrum is unavailable. The model system consists of the analytical models and computer simulations for remote sensing mechanism. The spatial scale of the models is from the material (such as leaf, soil) to end-member (such as canopy) to remote sensing pixel (such as a pixel consisted of wheat, road and lake).The user enters object/place, time, observing direction, bands and spatial resolution,and the knowledge base provides the reference spectrum and relevant description. The spectrum of vegetation depends on the seasons, and it is impossible to measure the spectrum of vegetation at all times. So the vegetation parameters have to be extended temporally when the measured data is unavailable.Based on the knowledge of the vegetation expert system, the vegetation structure parameters and spatial pattern can be computed by the vegetation shaping models. The land surface parameters have to be scaled up/down when the pixel size is different to the size of view field of the measured data. The describing parameters of DTM and land-cover and soil should be based on the pixel size. Selecting remote sensing physical models for simulation depends on three factors:1)spectral band: visible light & near infrared, thermal infrared, and microwave;2)spatial scale on which the models are built;and 3)land surface type, grass or forest. In other words, radiation transfer model, geometric optics model or compositive scene model is more suitable to this type. The agriculture remote sensing applications based on the spectral knowledge base also is discussed. The approach is a feasible quantitative remote sensing way in agriculture.
  • ARTICLES
    WANG Jinggui, YANG Xiaomei, DU Yunyan, SU Fenzhen, CHEN Xiufa
    2002, 4(4): 16-23.
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    The management of Remote Sensing images is based on files at present, but this management method has many disadvantages for data sharing, we need new methods to manage images data. ArcSDE, a key component of ArcGIS developed by Environment System Research Institute of America, is an open architecture and GIS gateway to connect GIS to RDBMS, such as Oracle, Microsoft SQL Server, DB2, Informix and so on. Based on the understanding of architecture and principles of ArcSDE, this paper found that using ArcSDE to build a RS image database is an effective way except for some limitations, and developed a method of building image database using ArcSDE tools, and took building remote sensing image database of Chinese coastal zone as a case study. During the case study, some problems were met and corresponding resolutions were identified:The storage of overlap parts between images is not very effective when mosaicing is done to them, especially for those Nodata area. During the storage when an overlap image data comes ArcSDE simply rewrites the data of these overlapped blocks. Therefore, the blocks with values have to be rewritten by other blocks with Nodata from another image.The authors provided a resolution to this problem, that is to customize the storing procedure when an overlap block comes. The system checks each pixel value of blocks that will rewrite and blocks that will be rewritten. If the rewriting blocks contain Nodata pixels while the rewritten blocks have values in corresponding locations, the rewriting action will be cancelled in these locations or pixels, otherwise, the rewriting action will be executed. This method can ensure that after mosaicing each pixel of overlap parts will have value as long as one of those images that take part in mosaic has value on that location. Searching and retrieving functions of raster data are not as flexible vector data, users can improve searching and retrieving functions of raster datasets if some vector feature classes were merged into these raster datasets, and we can even search and retrieve raster data through toponyms or placenames if a powerful gazetteer was constructed.
  • ARTICLES
    HOU Xiyong, SUN Xihua
    2002, 4(4): 24-29.
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    Since relations among population, land and grain have long been in an intense state in China,studies on Cultivated Land Potential Grain Productivity (CLPGP) and Population Carrying Capacity (PCC) are becoming more and more important. Although achievements have been made in this study field, most of the researches were at macro spatial scales of national and regional levels. This article takes Changqing county of Jinan city, as an example. It belongs to a microscopic region with an area of 1209.19km2. CLPGP and PCC were analyzed with GIS and RS. First, five kinds of CLPGP, i.e., Photosynthetic Productivity, Photosynthetic Thermal Productivity, Climatic Productivity, Potential Land Productivity and Potential Social Productivity, were calculated accurately according to the theory of Limiting Factor Converse Modification. The former three kinds of CLPGP were calculated as the average of the whole county due to their obvious spatial homogeneity. Otherwise, because of the tremendous spatial heterogeneity that determined by the diversity and complexity of limiting factors, the latter two kinds of CLPGP were calculated by the basic grid pixel of 30m×30m in size. In detail, exact mathematic models and the availability of large scale (1∶50000 or 1∶10000) thematic maps of all kinds of physical factors, topographic maps, land use maps, high resolution Landsat TM data and high quality statistical data have ensured the accuracy of the outputs. The results (average value) were: 7681.4 kg/mu (15mu equals 1ha), 4524.6 kg/mu, 2083.1kg/mu, 1240.3 kg/mu and 713.8kg/mu respectively. Then, based on Potential Social Productivity computation results, database of existing cultivated land and statistical data of grain yield, the Gross Potential Social Productivity and the Potentialyield Increase were calculated respectively. Next, scenarios of grain production in the near future were predicted based on the comprehensive reviews of the history. And the population growth tendency was studied carefully with the mathematic model of GM (1,1), which has been programmed with BASIC language. As a result, gross population data of 20012035, a temporal scale that we are interested in, was got. An additional work has to be done was the estimation of per capita consumption capability in the near future. At last, the PCC was discussed. Discussion and conclusions:(1) All the five kinds of CLPGP are very high, and the Potential Land Productivity and the Potential Social Productivity are characterized by their outstanding spatial heterogeneity. But, (2) restricted by physical environment characters and social-economic development levels, such as topographical characters, hydrological characters, precipitation and irrigation conditions, it will be a hard work to improve grain production remarkably in the near future. At the same time, population growth rate is very high and the consumption level of local residents will be dramatically improved continuously. Therefore, (3) problem of foodstuff deficiency may occur in the near future (perhaps before 2035). This potential foodstuff crisis has already drawn the attention of both government official and scientists. (4) To avoid the potential crisis and ensure the sustainability of socio-economic development, two aspects of effective approach should be reinforced: On the one hand, it is necessary to go on enforcing family planning policy in order to control the stupendous population as well as its striking increase speed. On the other hand, "limiting factors nowadays may be facilitative factors tomorrow." So it is necessary to make progress towards the target of improving grain production with new techniques that can weaken or counteract the effects of limiting factors.
  • ARTICLES
    XIA Shudong, LI Qi, CHENG Jicheng
    2002, 4(4): 30-35.
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    The Grid refers to an computer network infrastructure that enables the geographical distributed computing resource,storage resource,network resource,software resource,data resource,information resource et al, to be integrated into a logistic one.Grid can provide integrated information application services for users as if it were a supercomputer.Now Grid has become a hot issue of reserch and development throughout the world. Spatial Information Grid (SIG)is the fundmental application of Grid technology in spatial information application service fields such as digital city. In fact, Spatial Information Grid is an intelligent information infrastructure providing integrated spatial information application services for users by using existing spatial information infrastructure and spatial information network protocol standard.In this intelligent information infrastructure, spatial information processing is distributed and intelligent user can acess spatial information resource through only one logistic portal. The architecture and key technology of spatial information grid are the most important issues.In this paper,at first,the background of thriving and prosperous Grid reserch and the proceeding of Grid research in China and abroad are analyzed.Based on Open Grid Services Architecture(OGSA),the Three-Layer Grid Architecture Model(Grid resource layer,system management layer or Grid Operating System,application service layer) is established,then the XML based Resource Markup Language(RML) as the resource information describing language in resource management and multi-layer grid node autonomous task scheduler in grid operation system are presented,At last,the Geo-Agent based Architecture of Spatial Information Grid is presented, it is a prototype of Common Agent Request Broker Architecture(CARBA) application in spatial information domain.Some important issues in Spatial Information Grid such as spatial information express and spatial metadata, spatial information connection and coherence, the intelligentization of Spatial Information Grid and the security of Spatial Information Grid are discussed. Spatial Information Grid will influence the development of Large-scale Geographic Information System deeply. Spatial Information Grid will also boost the evolution of digital city and digital earth.
  • ARTICLES
    FANG Jinyun, HE Jianbang
    2002, 4(4): 34-42.
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    Grid geographical information system (Grid GIS) is a hardware infrastructure and distributed software platform to share information and service collaboratively for wide-area spatial information distributed processing. On the internet, computational, storage, and network resources are heterogeneous and reside in different security domains. This makes the spatial data processing grid environment much more challenging than traditional distributed computing environments, which typically consist of homogeneous machines under the control of a distributed operating system. Grid GIS is the virtual super-computing environment for spatial data handling which connects computers, spatial databases, huge data store system, other GIS, virtual reality systems,and so on in the heterogeneous application environment to one system (Grid GIS). In this paper, we discuss the basic spatial services that must be provided by a grid GIS infrastructure to enable high-performance applications to be distributed over the wide area. We survey recent technical papers on grids and spatial data processing and focus particularly on the key implementation techniques for GRID GIS,such as, spatial data(metadata) standard, spatial data service standard, distributed spatial object, component and component database, spatial data interoperability and middleware, from the Globus project and SIG project. We also propose the 5 tiers model, which consists of client application, service converting bridge, function server,spatial data engine and database server, for architecture of Grid GIS on the basis of analysis the feature of spatial data in the network. Our solution for data sharing and service cooperatively is to decompose the name space (metadata) into a top layer which is under centralized control, and at the lowest level, where the resources themselves reside and the need for complex relationships is greater. The communication at the top level is GXML. For instance, a portal may request information from a GIS server. It would issue a query in a language like XPath (step 1). The XPath query would be sent to the SQL database server (2), which converts it to an SQL query, executes the query (3) and returns the result as a GXML document (4). Transformation to the document may be necessary (5) before returning the document to the portal.
  • ARTICLES
    XIE Chuanjie, MENG Xuelian, WAN Hongtao, YAO Changqing
    2002, 4(4): 43-49.
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    With the development of technologies of the computer graphics and computer-human interface, a new kind of Geographical Information System, Virtual GIS(VGIS or VRGIS), which is based on the traditional multi-dimensional Geographical Information System, is emerging. VRGIS extends the usage of GIS, at the same time, brings new problems for the design of the GIS. The data model always is important technology for any kind of GIS, same as to VRGIS. After discussing current researches of data model for VRGIS, the deficiency of the data model of current VRGIS is obvious. In the paper, a new data model for VRGIS is introduced in detail, in which the hierarchical structure objects are introduced in order to support the geographic data to be managed effectively by spatial database and to be displayed in the GVE. Of course, the new data model is complex, and is hard to implement in common commercial relational database. In the paper, the data model is implemented by a active object-oriented database system, moreover, the event attributes were designed as a part of the geographic objects in the data model with the help of the database system. At last, two application figures of the VRGIS system are illustrated.
  • ARTICLES
    LIAO Yongfeng, YANG Linsheng, WANG Wuyi
    2002, 4(4): 50-55.
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    After the Second World War, development of socio-economy and advancement in science and technology have dramatically changed the global health situation and, consequently, have changed knowledge of human on environment-health issues. More emphasis are put on environmental factors, especially population, health and social context, while stresses on diseases itself are becoming fainter. Since the nineties of the last century, the core of environment-health studies has been transferred to improvement of well-being, health status and body function from the traditional disease controlling. A case in point is the Concept Frame of Population Health by Russell. Mapping, which had ever played an important role in analyzing the interrelation between diseases and environmental factors and revealing causation of epidemic, can not meet the need of environmental changes. GIS, for powerful captivities in multi-source data integration and spatial-temporal analysis, gradually takes the place of mapping and becomes a primary tool to help professionals resolving environment-health issues and to help officials of health to perform multi-level administrating, policy making and tasks planning. At present, applications of GIS in environment-health mainly focus on global and regional environment-health issues, where buffer zone analysis, spatial analysis and spatial-temporal analysis are the three main kinds of techniques frequently adopted. In the way of environment-health management, application of GIS still stays at the exploratory stage and lacks support of systematic theory with many limitations to be overcome. The primary three limitations are data quality, shortage of GIS technology and lack of GIS knowledge for researchers and officials. The data quality is the most serious problem confronted us. It is thus clear application of GIS to management and planning on environment-health is a fairly promising field, whose target will be to integrate GIS technology with other professional analysis tools to develop comprehensive environment health management information system.
  • ARTICLES
    ZHUO Baoxi
    2002, 4(4): 56-62.
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    This paper will show the importance of hydrogeologic survey in tunnel by presenting examples of troubles in tunnels' construction and administration caused by unascertained hydrogeologic conditions. A new approach named as Quantitative Remote Sensing Interpretation Application Model was put forward and the differences of this model from the traditional Qualitative Remote Sensing Interpretation Application Model in evaluating the degrees of water enrichment in tunnels were described in this paper. The core of applying this model to evaluate the water enrichment in tunnels is to assess the enrichment degrees using the empirical formula for remote sensing evaluating water enrichment degree in tunnel with quantitative remote sensing interpretation. This method is based on the remote sensing geological interpretation. It quantifies the interpretations and the factors affecting the water enrichment in tunnels, brings them into empirical formula in form of fractions, and obtains the enrichment degrees according to the derived fractions from the formula. As a focal point, this paper introduced the detail approach and steps in applying the empirical formula for remote sensing evaluating water enrichment degree in tunnel, illustrated by the two examples from qinling tunnel of Xi'an-Ankang railway and Jiazhujing tunnel of Nanning-Kunming railway.The construction has proofed these assessments and demonstrated that the predicted enrichment degrees were little different from the real ones. The paper also presented some noticeable problems encountered in application of the empirical formula for remote sensing evaluating water enrichment degree in tunnel. In the conclusion, the paper pointed out that the empirical formula for remote sensing evaluating water enrichment degree in tunnel was a new application model which was different largely from the traditional qualitative remote sensing interpretation application ones. This model made the water enrichment evaluation more reliable and its processing was more simple and feasible. No similar report on this kind of method has been found in recent data retrievals. This achievement can be applied in the hydrogeologic evaluation and predictions before tunnel constructions for railways, highways, and water conservancy works. It has beneficial effects on lowering the surveying cost, heightening the surveying quality, raising the surveying efficiency and improving labor conditions.
  • ARTICLES
    LIU Bokun, MENG Shuying, LI Shujing, WANG Xueyou
    2002, 4(4): 63-68,119.
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    Having made the most of "3S" advantages, it is the first time during the construction of Three Gorges Project to monitor the dynamic changes of settlement along the Three Gorges Reservoir area of the Yangtze River by utilizing the combination of space and aerial borne data such as ETM+, SPOT, IKONOS with characteristics of multi-data, multi-temporal and multi-resolution. In addition, through the project of dynamic monitoring on settlement in the Three Gorges Reservoir area ( Fengjie-Badong), great strides towards the movements and settlement of population, distribution of newly-developed land, change of land use and land structure, prevention of geological hazard including its derived geological hazard, protection of environment and ecology as well as improvement of economic structure in the area have been made, indeed. Also,many basic data and achievements of scientific research have been collected and attained due to the construction of this project. Particularly, it can be regarded as the first achievement attained during the application of remote sensing technology using the high resolution satellite and aerial borne data received from those satellites of the latest generation launched in 1999. The outcome of research can provide an assistance while the final decision is to be made scientifically in terms of implementation of settlement planning, administration and sustainable development of the Three Gorges Reservoir area. Based on such a practice, it shows that the application of remote sensing in dynamic monitoring settlement is of success in the project. It can be regarded as a technology that is updated and accurate as well.
  • ARTICLES
    DAI Jinfang
    2002, 4(4): 69-74.
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    The contradiction between the increased land resources requirement by economic development and limited land resources is one of the main contradictions in sustainable economic development of the Yangtze River Delta.Accompanied by the rapid development of the Yangtze River Delta's economy, the pace of urbanization and industrialization was speeded up, and land resources also changed rapidly due to intensified exploitation. With sustainable progress in economy, the conflict between human and land resources becomes fiercer, which is an important factor that restricts the sustainable and harmonious development of national economy. The Yangtze River deltaic area is the economic-advanced area in China, which is rare in Chinese history that can produce crop yield largely and steadily in huge zone. Based on the quantitative analysis of the existing situation of the Yangtze River Delta's land resources, particularly cultivated land resources, by remote sensing and GIS method, this paper was prepared based on 15 years(1985~2000)of monitoring data with Xishan city in Jiangsu province as a typical case. According to in-depth analyses of the quantity of land resources, characters of their distribution and the rule of their dynamic changes, this paper displays and reconstructs the spatial and temporal course of land resources in this area, and clarifies that these dynamic changes of the area are strongly influenced by human activities and the main factors exerting dominant effects on them are policies, economic development and population growth. Combined with the structural characters of land resources in this area and the analysis of their development trends, the author considers that in a long period of time, there will be an inevitable decrease in this area's cultivated land. Cultivated land not only has its economic value, but also ecological and social benefits.The loss of the ecological and social benefits after cultivated land's conversion should be necessarily included in the cost of cultivated land use. Only having done this can we restrain the trend of occupying cultivated land from economy, solve the low-efficiency problem in cultivated land use ultimately and establish the rule of cultivated land protection by market method.
  • ARTICLES
    WANG Xiaoqin, WANG Qinmin, LIU Gaohuan, LI Huiguo
    2002, 4(4): 75-79.
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    Based on multi-temporal remote sensing images of the Yellow River Delta acquired in 1984, 1986, 1989, 1992, 1995 and 1999, together with auxiliary data and geo-knowledge, oil fields concentrated area was delineated and land use elements were extracted. With the spatial analysis function of Geological Information System, land use changes in oil fields concentrated area from 1984 to 1999 were analyzed. The quantity of land use types and changes, and the spatial distribution of land use change in different periods were acquired. In the 15 years from 1984 to 1999, the area of oil fields increased from 245.7km2 to 799.69km2 and the density of wells increased too. The average annual increased rate was 8.18%, and the rate of increase was more rapid before 1989 than that after 1989. Before 1984, the oil fields were concentrated in the Kenli County, Dongying District to the south of the Yellow River and Hekou District to the north of the Yellow River. The newly developed oil fields concentrated area mainly lies to the Bohai Bay to the north of the Yellow River Delta,which leads to the main changes ranging from tidal flat to saline-alkaline land. Because of eco-environmentally extremely fragileness in the study area, the land use types changed frequently with higher proportion of the affected area. The main changes in oil fields concentrated area were conversions between shrub-grassland and saline-alkaline land. This study shows that it is possible to delineate the oil fields concentrated area and extract land use elements with remote sensing images and offer timely information for oil fields development and management.
  • ARTICLES
    ZHOU Changbao, HUANG Weigen, ZHANG Huaguo, LI Dongling, XIAO Qingmei, FU Bin, YANG Jinsong, SHI Aiqin, LOU Xiulin
    2002, 4(4): 80-85.
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    IKONOS satellite images are important information sources with one of the highest spatial resolutions as today's remote sensing application. The islands are complex objects with multi-dimensions and multi-scales, and there are special requirements for their detections. Nanji islands are typical representative areas of multi-kinds of biotic resources. Their detections for environment and resources are of a great potential by using IKONOS remote sensing methods. The paper shows some results on the detection of coastlines and their structures as well as some object features over sea from Nanji Islands by using IKONOS remote sensing images.Nanji Islands National Marine Nature Reserve was established in September 1990.It is located between 27°24′30″-27°30′00″N and 120°56′30″-121°08′30″E with an area of about 200 km2. The reserve is a marine ecosystem in nature, which mainly protects shellfish, algae and their ecological environment.There are 421 species of shellfish, 174 species of macro-benthic-algae, 459 species of macro-algae, 397 species of fishes, 257 species of crustaceans and 158 species of other marine creatures in the reserve.These kinds of biological resources exist mainly at the tidal zone areas. IKONOS imagery processing and extraction of key information are very important in achieving the coastline and inland features and their parameter estimations. The geometric correction of remote sensing images includes the selection of transfer schemes and correcting methods, achievement of the controlling points, the boundaries of output images, pixel sizes of images and re-samples of imagery grey scale. The transfer schemes are divided into both immediate and mediate methods. Mediate method is dealt with in the study. With regard to transfer method identification, the second order multinomial is chosen. More than 6 control points are required because there are 12 unknown data in the multinomial.Concerning IKONOS image fusion,there are quite a number of approaches for this purpose, for example HIS, essential component analysis, wavelet transfer and so on. Here HIS transfer combines with other methods. The fusion is carried out after image enhancement. The imagery fusion is perfected by using part of IKONOS's black-and- white band and multi-spectral images. Of them, multi-spectral images are chosen as the groups of 432 or 342 and 321 respectively, and then the excellent images with rich information are obtained. As for the extraction of coastline and island land covers, Envi software and supervised classification are applied to extract various informations in the study. Data on coastline, the construction of coastal zone, the natural and man-made objects and sea surface objects as well as land coverage and so on have been obtained based on information extraction from IKONOS images. The results indicate that it is of great potential to conduct large scale mapping of the islands and detect small marine objects. The developments of coastal and marine remote sensing applications for IKONOS and other new satellite images with high resolutions are very important. The problems and difficulty in applying IKONOS images are also discussed.
  • ARTICLES
    ZHANG Lei
    2002, 4(4): 86-92.
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    Concerning the paradox in evaluating the national resources-environmental security from both very traditional and very complex ones, a modest method, namely key factors analysis, is employed by this paper. A result of the proposed analysis on the 10 selected countries with a population over 100 million of each in the world shows that all the countries could be categorized as three types, namely high, lower and the lowest, in their national resource-environmental security evaluations.The result also implies that curtail factors to determine a country's place in the comparative study is the overall coordinated situation of the cultivated land, water resource, minerals and ecological environment, and it is particularly true for the large developing countrys like China with a population over 1.2 billion.In order to release a higher pressure on the weakening resource-environmental base for most of the developing countries, there are some things must be done. According to the common practices of the whole world, this paper raises the followings suggestions: tightening population control first of all; widening the national resource-environment base through international trade secondly; intensifying the national resource value-added process thirdly; and putting more energy into the national environment protection finally.
  • ARTICLES
    BI Shuoben, LV Guonian, LI Anbo, XU Xiuhua
    2002, 4(4): 93-96.
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    In the process of analysing "The Surface Construction Information System of Daqing Oilfield" which is based on the technologies of geographical information system (GIS), this article puts forward four leading principles of developing a large-scale GIS software engineering successfully. Firstly, a large-scale GIS software engineering, which involves many professionals who belong to different departments, different subject areas and different administrative levels, is managed by the chief leader of the first party, otherwise it would be difficult to assort with so many departments and consequently it would be difficult to carry the engineering project into execution. Secondly, a large-scale GIS software engineering is a specialization system engineering, so it is necessary for the technical staff and the software developers to cooperate intimately. The third principle is that the first party personnel go deep into the process of software developing and then master the technique for updating and maintaining the GIS software. Fourthly, in order to fix on the second party, the bidding documents are examined by experts. Besides, three groups are needed to ensure the successful execution, namely the leading group, the technical management group, and the developing group which works together with the second party in the process of software developing. The leading group has two level groups, the first-level group charges the engineering project, the second-level group carries out the task, and feedbacks information to the first-level group. The technical management group mainly consists of persons who come from the technical management department. The members of the developing group come from different departments, and different subject areas. Finally, the working mechanism of a large-scale GIS software engineering is that the engineering project is managed by the technical management department and the production department severally, and is implemented by the administrative department concentrative.
  • ARTICLES
    LI Zhi, CHEN Qiang
    2002, 4(4): 97-100.
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    In this paper, the applications of Digital Earth in oil and gas exploration and production, oilfield management and decision-making, the Digital Oilfield are researched. The fundamental technologies of Digital Earth in development and application systems can be summarized as 4I, they are Immersive Visualization, Internet Enabled, Integrated Data warehousing, and Intelligent Modeling. Digital Earth is not just Web-GIS, VR-GIS, or online 3S system (GIS, GPS, RS). In order to extend Digital Earth to Digital Oilfield, the SIM (Subsurface Imaging and Modeling) is considered, then the Digital Earth will be used for scientific and industrial exploring from Earth surface to subsurface, even to Earth mantle and core, such as digital oilfield, digital lithosphere, and digital biosphere, for industrial and social information management, and for innovative ways of education and entertainment. The main improvement of Digital Oilfield in contrast to the original great computer center is that many oilfields have focused on oil and gas integrated forecasting, reservoir dynamic modeling,oilfield management and decision making, and exploration data warehousing. The immersive environment can provide stereoscopic 3D images of the complex data, which makes users easier to understand, easy to do collaborative teamwork, easy to interpret, easy to make decision, easy to manage, easy to do perceptual computing, and so on. A typical Digital Oilfield system can be divided into the following aspects: super workstation or computer cluster for computing and graphics generating, virtual reality and 3D projection systems for immersive visualization, wide band network, storage area network as Data warehouse, virtual reality system software, oilfield data processing software, develop software, data sharing software for multi-source and hetero-database seamless integration and so on. Suggestions on how to realize a Digital Oilfield system and its configuration are put forward. The key related technologies and applications of digital oilfield are analyzed in detail. Finally, we concluded that the only way to solve the problems that oil and gas department confronted with is to adopt new ideas, new theories and new technologies.
  • ARTICLES
    XIONG Anyuan
    2002, 4(4): 101-104.
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    This paper focuses on what is the meaning of digital meteorology,namely,digital accepting, intelligentized processing, visualizing distribution, and network service for meteorological information. The components of digital meteorology system were analysed. The foundation of digital meteorology is the digital meteorological datum that can be accessed by computer. The core of digital meteorology focuses on processing of meteorological data and building of the outputs that can express atmospheric state at present and in future. The main purpose of digital meteorological is the services of the data and outputs for society and all people through international networks. The system of digital meteorology is the comprehensive information system that is composed of the monitoring system for earth climate and atmosphere, and archiving and retrieving system of meteorological data, and analyzing and predicting system of the atmospheric environment, and service system for sharing meteorological information. Finally, the paper investigated how to develop the digital meteorology based on technology, thoughts and stratagem.
  • ARTICLES
    LIU Shuren
    2002, 4(4): 105-108.
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    According to records of Biography of Buddhism (also known as Biography of Fa Xian),Buddhist Monk Fa Xian in Eastern Jin Dynasty returned from Xi Lan by business ship in 412. Due to strong wind during the sail, he had to take 105 days across the Pacific Ocean to the country Ye An Ti. Ye An Ti called in the book in Chinese may be near Mexico. So we say he arrived in America 1080 years earlier than Christopher Columbus. It is recorded that he stayed there for 5 months, prepared enough food, spent 115 days across the Pacific Ocean again, and landed in Qingdao finally.
  • ARTICLES
    YANG Guang, LIU Xiangnan
    2002, 4(4): 109-114.
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    As a recent map form, electronic map have broad application value. This paper introduces electronic character and meaning in the first place. Popular science tour is a new tour form which collects tour and popular science. To improve the development of the popular science traveling industry in Northeast China, we have developed Northeast Popular Science Electronic Map.This electronic map can provide fine service for tourists and help selecting touring routes.It can also provide basis for layout and direct building of popular science tour. So it is important to develop popular science tour electronic map.In this paper we have discussed the popular science traveling characteristics and put forward the research goal and function structure of information system of the Northeast popular science traveling design. In recent years, component is one of the GIS software development tends. MapX control have powerful electronic map edition function, so we select MapX control as the main developing tool. This paper based on analyzing characteristic of MapX and application instance, discusses common methods in developing popular science tour electronic map with the aid of MapX control. The popular science traveling industry in Northeast China uses Visual basic as programme tool. Hence,it is the key concerning how to realize the basic function of combining MapX control with Visual basic programme.This paper proposes technology to realize map layer operation,double direction selection,database link, and analyzes amply in allusion to some technical difficulty and solutions for further development.