(Serialization 1) two-dimensional and Three-dimensional GIS system developed by VC, OpenGL, and ArcGIS Engine

 

I. Preface

As we all know, two-dimensionalGISWith the rapid development of computer software and hardware and relational databasesGISTechnologies have been improved. It has unparalleled advantages in analyzing geographical information. Some macro geographic information, one-dimensional geographic information, such as rivers and highways, and two-dimensional geographic information, such as vegetation, lakes, and population quantity, in terms of analyzing and processing the geographical information, it is suitable for the use of two-dimensionalGISSystem.Two-dimensional GIS Started from 20 Century 60 Today, it has penetrated all walks of life in the society, such as land management, electricity, telecommunications, water conservancy, fire fighting, transportation, planning, etc. GIS It has its own insurmountable defects. It is essentially a system based on abstract symbols and cannot truly reproduce the three-dimensional objective world. . With the rapid development of information technology, especially the digital earth ( Digital Earth ) Proposal and implementation , And GIS The application depth and breadth are constantly expanding, two-dimensional GIS Users cannot meet their needs. GIS More urgent. With the development of computer display devices and storage devices GIS It has also achieved some development, GIS Going through a process from two-dimensional to three-dimensional development .

3DGISThe biggest advantage is that it can truly reproduce geographical information in the real environment, such as topography and landform. Using 3DGISTechnology andDEMTexture data can generate realistic terrain and landform, as well as real-time roaming.GISFunctions that can be achieved by technology must also be composed of three dimensionsGISTechnical implementation. For example, to better understand the results of spatial query and analysis and improve the level of spatial analysis, it is necessary to restore the three-dimensional spatial relationship and perform perspective display. But 3DGISJust a short start, without the strong support of mature spatial data models, spatial databases cannot fully express the complex relationships of spatial entities.3D GIS The core is terrain 3D visualization and query analysis. 20 Century 90 It has always been one of the hot topics of Development and Application in the geographic information system field. 3D terrain visualization is a process that uses the digital elevation model ( DEM Is a hot topic in graphics research. , And DEM 3D data display is the foundation of 3D terrain visualization. . In recent years, terrain 3D visualization technology has been widely used in geographic information systems, flood control decision-making systems, virtual environment simulation, land and resources management, and other fields. With the development of science and technology, 3D terrain visualization has gradually become the frontier and main means for the current study of river, lake and port flood prediction and Bed Evolution Analysis, it is also an effective method for rapid and timely reproduction of 3D terrain information and analysis. . Existing 3D GIS In the system, the system functions have achieved good results in 3D scenario visualization and real-time roaming, but the query and analysis functions are relatively weak. However, the query and analysis functions are in three dimensions. GIS Is very important in the implementation and application, it makes three-dimensional GIS Supporting Decision-making .

Taking into account the above situations and factors, the author believes that the current hybrid model based on two-dimensional development and supplemented by three-dimensional development GIS As the main goal, it is not appropriate to simply develop 3D GIS . In the current GIS Industry, two-dimensional GIS Has been able to meet most of the actual needs, for 3D GIS The demand is still only a small part. Current 3D GIS In terms of 3D data acquisition, processing and storage of large data volumes, 3D visualization, and 3D space analysis, it cannot meet the needs of large-scale commercial applications with good cost effectiveness. If 3D GIS , Will inevitably spend a lot of system construction costs, in two-dimensional GIS To meet your needs, you do not have to pursue high performance. Of course, it is not excluded that some units have completely developed three dimensions. GIS To meet the specific needs of some industries, such as military, mining, petroleum exploration, geological structure research and so on. So the two-dimensional GIS And 3D GIS It is of great practical value to carry out research on the combination of vector data and three-dimensional visualization of terrain. If three-dimensional visualization is used to integrate vector data and query and analyze its related attributes GIS The advantages of using in 3D terrain visualization, make two-dimensional GIS And 3D GIS A good combination of military, civil aviation, and meteorology And other industries have very important practical significance.

At present, different application purposes often require two-dimensional GIS And 3D GIS The two methods work in turn, rather than a single one. Therefore GIS And 3D GISIt is an economic and practical idea to give full play to the advantages of the two. This is the purpose of this study. Therefore, it is of great practical significance to develop a system that integrates vector data with three-dimensional visualization of terrain. This system is divided into two parts: 2D and 3D. MFC And ArcGIS Engine Implementation, the 3D part adopts ATL And OpenGL Designed ActiveX Control, ActiveX Controls are highly integrated and can be released to any online user terminal. Therefore, this thesis integrates the 3D part into the 2D part to form an integrated system between the 2D view and the 3D view. ActiveX Control, this method is very flexible, when ActiveX When the control version changes, you do not have to update it manually. Of course, it cannot be simply stacked into a set of two-dimensional GIS And 3D GISMore importantly, the two-dimensional and three-dimensional components can interact with each other. Therefore, this paper combines two-dimensional and three-dimensional components to achieve interaction between two-dimensional and three-dimensional components. Describes the overall design concept of the system.

The system is constructed by two-dimensional and three-dimensional parts, such As shown in. The system is divided into two views: the Left view is a two-dimensional part, and the right view is a three-dimensional part. The design and implementation of two-dimensional and three-dimensional interaction are described in detail below, the test was conducted with data from a certain place.