首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 250 毫秒
1.
With the rapid development of global information highway,multimedia communication technology plays a more and more important role in national economic and social development.However,the multimedia communication system is a complicated real time distributed system and its software is difficult to develop.In order to improve the rapid development and application of the multimedia communication technology,there is an urgent need to carry out the basic research work of software development platform in this field.……  相似文献   

2.
Urban geo-environment mainly concerns those regards in and around a city,such as the movement of earth crust and earth surface,conditions of hydrology,geology,geography and meteorology.The relevant studies on geo-disaster reduction and the influences resulted from human activities on the geo-environment are included as well.It is stressed in the paper that geo-environmental protection and management are of significance to the sustainable development for Chinese cities.  相似文献   

3.
This paper deals with the content,purpose and significance of digital agriculture,and gives a brief introduction to digital earth,digital China and digital agriculture abroad.The main content of digital agriculture includes the construction of database,Metadata standard,monitoring system,forecasting and decision-making system,information-releasing system.The main technical supports of digital agriculture are 3S technology,Metadata management technology,fast-handling technology of remote sensing,the technology of computer wide-band network and virtual reality,intelligent agriculture machinery and field real-time information collecting technology.The advantages of implementing digital agriculture in China and the problems worthy of attention are pointed out as well.  相似文献   

4.
This paper reports some researches on distribution of large volume image data using techniques of the Mixed Mode of Java Servlet and COM on Web. The architecture and key technologies are discussed in detail. The web distribution system of image is implemented and the system is tested by the application instances. At last, the advantages and disadvantages for this web image distribution mode are analyzed.  相似文献   

5.
LBS (location-based service) is a remarkable outcome of the development from GIS to geospatial information service. Faced by the requirements of geospatial information from the masses and the opportunity provided by the next generation Internet and Web 2.0, a new model of geospatial information service based on DMI (digital measurable image) is presented. First, the concept of LBS and the opportunities of Web 2.0 are introduced, then the characteristic of DMI is discussed. Taking the Image City·Wuhan as an ...  相似文献   

6.
GIS applications to mobile devices are becoming increasingly popular, utilizing a di-verserange of devices. Many of these devices suffer from serious constraints in three main areas: processor speed, memory space and screen size. This paper presents a (;IS application, called “MacauMap“. that is intended for heavily resource-constrained handheld devices. MacauMap is a tourism oriented map application of the Macau territory for PalmOS and Pocket PC personal digital assistants. It was designed to perform satisfactorily on devices with as little as 16 MHz processor speed, and requires only 500 KB available memory for the GIS application and all GIS data. Memory requirements are kept low through a specially designed data format. The main challenge of satisfactory map drawing speed is addressed through a variety of techniques that were developed for this application. The paper describes the application‘s data format, outlines the map drawing techniques, and points out the areas for future development.  相似文献   

7.
A new computational procedure for derivation of marine geoid on a 2.5′×2.5′grid in a non-tidal system over the South China Sea and the Philippine Sea from multi-satellite altimeter sea surface heights is discussed. Single-and dual-satellite crossovers were performed, and components of deflections of the vertical were determined at the crossover positions using Sand-well's computational theory, and gridded onto a 2.5′×2.5′resolution grid by employing the Shepard's interpolation procedure. 2.5′×2.5′grid of EGM96-derived components of deflections of the vertical and geoid heights were then used as reference global geopotential model quantities in a remove-restore procedure to implement the Molodensky-like formula via 1D-FFT technique to predict the geoid heights over the South China Sea and the Philippine Sea from the gridded altimeter-derived components of deflec-tions of the vertical. Statistical comparisons between the altimeter-and the EGM96- derived geoid heights showed that there was a root-mean-square agreement of ±0.35 m between them in a region of less tectonically active geological structures. However, over areas of tectonically active structures such as the Philippine trench, differences of about -19.9 m were obtained.  相似文献   

8.
The components of map information are analyzed theoretically in this paper ,and the map information includes mainly the spatial information,attributive information and temporal characteristics information.Then the digital map entity is defined according to construction characteristics of the map information.Finally,on the basis of the analyses of the construction characteristics of digital map entity and present conceptual model of digital map database,an abstracted conceptual model of digital map database is presented.And the Normal Form theory of relational database is discussed particularly.  相似文献   

9.
主动式地理信息服务质量(QoAGIS)评估研究   总被引：2，自引：0，他引：2  
设计主动式地理信息服务质量(quolily of active geospatial information service,QoAGIS)评估系统,阐述主动式地理信息服务的内涵及其逻辑结构,提出AGIS质量评估指标的概念,并对其中的本征质量指标与广义质量指标的定量化实现进行研究,给出综合评估指标.最后,通过实验表明QoAGIS评估系统的适应性和可靠性.
Abstract：
Currently, the passive aspects of geospatial information service (GIS) and the unpredictability of QoGIS are unable to meet the applications in some deeper fields. A new evaluation system of quality of active geospatial information service (QoAGIS) is presented. The connotation and logical structure of AGIS is analyzed, in which it advanced basic event and its expression, event operation's methods, the expression of complex event and the driven rules, the indices of QoAGIS evaluation are presented, in which the intrinsic quality index and the generalized quality index are researched on. Finally the compositive evaluation index is calculated. The QoAGIS evaluation system has been used in an application of AGIS, the experiment indicated its adaptation and reliability.  相似文献   

10.
This paper integrates genetic algorithm and neural network techniques to build new temporal predicting analysis tools for geographic information system (GIS). These new GIS tools can be readily applied in a practical and appropriate manner in spatial and temporal research to patch the gaps in GIS data mining and knowledge discovery functions. The specific achievement here is the integration of related artificial intelligent technologies into GIS software to establish a conceptual spatial and temporal analysis framework. And, by using this framework to develop an artificial intelligent spatial and temporal information analyst (ASIA) system which then is fully utilized in the existing GIS package. This study of air pollutants forecasting provides a geographical practical case to prove the rationalization and justness of the conceptual temporal analysis framework.  相似文献   

11.
Application of GIS to estimate soil erosion using RUSLE   总被引：9，自引：0，他引：9  
This paper describes the use of the Arc/Info and ArcView GIS tools to estimate soil erosion with Universal Soil Loss Equation (USLE).Calculations are be done by using capabilities available.This study start with a digital elevation model(DEM) of Shaanxi,which was created by digitizing contour and spot heights from the topographic map on 1:250000 scale and grid themes for the USLE K and C factors.It is note worthy that USLE K can be obtained by adding the K factor as an attribute to a soil theme‘s table.The C can be obtained from tables or using the information about land use and management given by USLE program.A land use theme can be used to add the C factors as an attribute field.The purpose of this study is to establish spatial information of soil erosion using USLE and GIS and discuss the analysis of the soil erosion and slope failures in GIS and formulate the possible framework.  相似文献   

12.
With the help of CCD images,the realization of high precision po-sitioning and measurement has become the basic standard for machine vision andreal time photogrammetry systems.However,deformation and other sorts ofdegradation occurring during transmission are major limiting factors of the preci-sion attainable with most current CCD cameras and frame grabbers.So a preciseradiometric and geometric transmission of images from CCD sensor to memory is afundamental aspect of CCD camera calibration.The geometric calibration system,which uses some image processing algorithms of the CCD camera based on the re-searched and developed system is discussed.The reliability and validity are alsodiscussed.The experimental results for the calibration of the CCD array will betaken as an important quality index for CCD evaluation.  相似文献   

13.
On the basis of previous work, this paper designs an intelligent agent based on virtual geographic environment (VGE) system that is characterized by huge data, rapid computation, multi-user, multi-thread and intelligence and issues challenges to traditional GIS models and algorithms. The new advances in software and hardware technology lay a reliable basis for system design, development and application.  相似文献   

14.
The methodology of catchment extraction especially from regular grid digital elevation models (DEMs) is briefly reviewed. Then an efficient algorithm, which combines vector process and traditional neighbourhood raster process, is designed for extracting the catchments and subcatchments from depressionless DEMs. The catchment area of each river in the grid DEM data is identified and delineated, then is divided into subcatchments as required. Compared to traditional processes, this method for identifying catchments focuses on the boundaries instead of the area inside the catchments and avoids the boundary intersection phenomena. Last, the algorithm is tested with a set of DEMs of different sizes, and the result proves that the computation efficiency and accuracy are better than existent methods.  相似文献   

15.
The main purpose to develop a Map Graphic Workstation on thewidely used micro-computer is that by it the whole processing of map data fromcapturing,managing,editing,updating to graphic outputting can be realized.Map Digitization System（MDS）is the software system to deal with the initial andalso the most important processing.In this paper,the authors introduce a MDSon a micro-computer based Map Grphic Workstation that has been qualitified forthe producation of digital map.Since the system is designed totally independentlyand in the general frame of the Map Graphic Workstation,the capturing and man-aging and other processings for map data are in an integral manner,in which theproducation of digital map can be fulfilled conveniently.At the same time,thesystem is flexible for function extension and widely applicable to the data from dif-ferent sources and with different information characterisitcs(e.g.,the processingof Chinese characters on map).  相似文献   

16.
From 2D to 3D GIS for CyberCity   总被引：3，自引：2，他引：1  
In order to understand the 3D landscape with many high buildings in a city, the 2D GIS has to be extended to 3D GIS. The further development of CyberCity has to include various applications of 3D scenes from the outdoor scenes to the indoor ones. In thispaper, some key techniques, such as data management method and dynamicalvisualization method for the outdoor and the indoor scenes, are discussed. The indoor scene is compared with the outdoor one. The idea of integratedrepresentation of the outdoor and the indoor scenes in CyberCity GIS is discussed.  相似文献   

17.
The fusion of VlSI （visual identity system Internet）, digital maps and Web GIS is presented. Web GIS interface interactive design with VISI needs to consider more new factors. VISI can provide the design principle, elements and contents for the Web GIS. The design of the Wuhan Bus Search System is fulfilled to confirm the validity and practicability of the fusion.  相似文献   

18.
An effective strategy and framework that adequately integrate the automated and manual processes for fast cartographic sounding selection is presented. The important submarine topographic features are extracted for important soundings selection, and an improved “ influence circle” algorithm is introduced for sounding selection. For automatic configuration of soundings distribution pattern, a special algorithm considering multi-factors is employed. A semi-automatic method for solving the ambiguous conflicts is described. On the basis of the algorithms and strategies a system named HGIS for fast cartographic sounding selection is developed and applied in Chinese Marine Safety Administration Bureau （CMSAB）. The application experiments show that the system is effective and reliable. At last some conclusions and the future work are given.  相似文献   

19.
Based on the developing tendency of present China‘s basic GIS,this paper discusses the designing idea for scales of 1∶10 000,1∶50 000,1∶250 000 and 1∶1 000 000 pyramidlike multilayer and multiresolution of the basic GIS.A technical line for the construction of basic GIS of the whole country and various provinces for sustainable development is put forward.And some important theoretical GIS issues touched by the technical process are discussed.  相似文献   

20.
Based on digital image processing technique, a real-time system is developed to monitor and detect the dynamic displacement of engineering structures. By processing pictures with a self-programmed software, the real-time coordinate of an object in a certain coordinate system can be obtained, and further dynamic displacement data and curve of the object can also be achieved. That is, automatic gathering and real-time processing of data can be carried out by this system simultaneously. For this system, first, an untouched monitoring technique is adopted, which can monitor or detect objects several to hundreds of meters apart; second, it has flexible installation condition and good monitoring precision of sub-millimeter degree; third, it is fit for dynamic, quasi-dynamic and static monitoring of large engineering structures. Through several tests and applications in large bridges, good reliability and dominance of the system is proved.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号