| After 40 years of development, Geographic Information System (referred to as GIS) , has become a mature technology, of geographic information management, and is widely used in many industries. Especially in recent years, three-dimensional GIS astonishing pace of development, there is a growing trend to replace the two-dimensional GIS. In three-dimensional GIS, the spatial objects are defined through the X, Y, Z three axes, it makes the spatial relationship is different from two-dimensional GIS, and has a higher degree of complexity. Compared with the two-dimensional GIS, the expression of the objective world of three-dimensional GIS can give people a more realistic feel, it shows three-dimensional modeling technology to the users of geospatial phenomena, not only able to express spatial relationships between objects of the plane, but also to describe and express the vertical relationship between them; In addition, three-dimensional spatial analysis of space objects and operations is also a three-dimensional GIS-specific functionality. Three-dimensional database is the core of three-dimensional GIS, and three-dimensional spatial analysis is its unique ability. And correspond with the enhance of function, three-dimensional GIS theoretical research and system-building work is also more complex than the two-dimensional GIS. Thus there is not a systematic and complete theory so far, and there is not a successful common platform for three-dimensional GIS. But for a number of industries such as mining, geology, oil and other terms, the three-dimensional GIS still has a very wide range of practical significance.Food security has become the focus of the current and hot issues, and food safety is a top priority of food security, for management and restoration of contaminated soil has become a worldwide problem demanding prompt solution. The major domestic food contamination, including food-borne diseases caused by micro-organisms, pesticide residues, heavy metals, and organic pollutants caused by chemical pollution, and illegal use of food additives caused by pollution. Among them, impact of pollution of agricultural land especially farmland on the quality of crops is basic and decisive, and in China, the soil pollution is deteriorating. Current agricultural land evaluation stresses the level of land productivity and sustainable land use evaluation, and advances to integration, quantification, accurate, information-oriented. Therefore, quality evaluation of agricultural land has been an important foundation for the work to ensure national food security. So the help of modern information technology, especially the three-dimensional GIS technology, decision support technology, with three-dimensional visualization of expression of the agricultural land, especially farmland soil fertility assessment and pollution assessment, as well as o propose a repair program optimizing intelligent geographic information systems for agricultural production has a broad meaning.This article describes a system relying on the project "Service-oriented agricultural land phytoremediation of three-dimensional GIS decision support system". The project is based on three-dimensional GIS features, and this project is an intelligent decision support system which can monitor agricultural land quality and propose auto-repair programs and a three-dimensional GIS technology, engineering application research.With the advances in the computer software industry, geographic information systems development techniques are also increasing. Component-based secondary development of GIS has become more and more popular development technology. The system described by this article execute integrated secondary development with ArcGIS Engine component technology and platform VC++6.0, and in the three-dimensional GIS platform achieve Three major functions: First, the browsing of massive and big scene three-dimensional terrain view; Second, three-dimensional analysis of three-dimensional terrain features, three-dimensional analysis capabilities include three-dimensional spatial analysis and attribute query functions; Third, the quality of agricultural land evaluation function. The browsing of massive and big scene three-dimensional terrain view Including the massive three-dimensional terrain data visualization, Zooming, navigation, flying, walking, positioning and Other high-speed roaming functions of three-dimensional terrain. Three-dimensional terrain spatial analysis function Including the adjustment of the base elevation, profile mapping, slope analysis, slope analysis, the mountain shadow mapping, cutting filling analysis and visualization domain analysis, etc. Attribute query functions including the coordinates of queries, slope queries, aspect queries, surface area queries, volume queries, and roughness degree queries. The quality of agricultural land evaluation function relies on three-dimensional visual interface and three-dimensional analysis functions, by means of expert knowledge and relevant national standards to achieve fertility evaluation of agricultural land and pollution assessment and other functions. Innovations this system is doing a lot of work in three-dimensional spatial analysis. This system completed slope queries, aspect queries, surface area queries, volume queries, and profile mapping. and improved three-dimensional analysis based on ArcGIS Engine and attribute query functions, simplified the analysis and properties of three-dimensional query operation based on ArcGIS original function.This article describes the system using ArcGIS Engine components developing method, It mainly uses GlobeControl to solve the problem that perfectly supporting big scene and huge amounts of data of three-dimensional terrain. ArcGIS Engine provides flexible use of the functions to complete three-dimensional analysis capabilities such as drawing the profile, the regional surface area and volume inquiry, solving the problem that lack of three-dimensional analysis features in three-dimensional GIS software. And combine the agricultural land quality evaluation function with three-dimensional terrain visualization, making the quality of the evaluation function be more intuitive presentation.So that function of the system is closer to the actual production of agricultural land and more practical. The system as a three-dimensional GIS application development of agricultural land to explore for other three-dimensional GIS system development provides a reference.Research content of this article establishes on three main functions of the system, The focus is to highlight the concept of three-dimensional GIS, as well as three-dimensional terrain visualization and three-dimensional analysis of the implementation, And describes the relevant background and ArcGIS Engine secondary development technologies. The main work of this paper is as follows:1) Introduces the relevant research background, three-dimensional GIS concepts and the significance of agricultural land three-dimensional GIS.2) Discusses the secondary development of technology, ArcGIS Engine, and a variety of secondary development of techniques are compared. And introduce simply the three-dimensional data model and three-dimensional modeling method. Also considers the implementation methods of ArcGIS Engine-based three-dimensional visualization and analysis, and the choice of development controls and basic data.3) Then introduces the concept of quality of agricultural land (Degree of agricultural land to meet crop growth and the extent of cleaner production, including agricultural land soil fertility and agricultural land environment) and Quality evaluation of agricultural land. Explain the various steps of fertility evaluation of the agricultural land and pollution assessment.4) Discusses the system design and database design, gives the system architecture design, the detailed design of system processes and the various subsystems.5) Introduces the concrete realization of the system, including three-dimensional browsing, three-dimensional analysis capabilities, attributes query function and quality of agricultural land evaluation function.
|
PDF Full Text Request