Sunlight Of Building Calculate On 3DGIS

With the rapid development of building and modifying cities in the nation, the increase of building height and the reduce of buildings'distance leads to the shortage of sunlight on resident building, which enhance the conflict between the land using rate and the quality of sunlight condition. So, insuring buildings'shapes and shadows, saving land and ensuring sunlight environment equality, and creating a pleasing condition for the citizen is an essential element in the city planning and design now.Traditional building sunshine calculated mainly "urban residential planning and design specifications" basis. However, the specification does not consider the terrain where the building as well as the concrete form of the building itself, lead to results unscientific and unreasonable. From the perspective of three-dimensional terrain to achieve the specific case study area, combined with different directions and different building size, building Sunlight obtained relatively more scientific, accurate and reasonable.Some relative key techniques including the design of 3D data model, database management based on Oracle, the fusion between CAD data and GIS data, sunlight analysis and so on are emphasized.The paper introduced the realization and the characteristics of some common sunlight analysis methods base on 3DGIS, including 3D dynamic shadow and the sunlight time's calculation of every kind of single point complex building at different districts in different season. Some sunshine on the current analysis compared the advantages and disadvantages. In this paper, using three-dimensional analysis of sunlight, and generates the sunlight computing systems. Through the system can generate three-dimensional space in any other point of occlusion at any point in the case. System directly calculate any point at a given moment in the sun elevation angle, solar azimuth, solar declination angle, the day of sunshine, year round sunshine and average annual sunshine time. This system taking into account the specific building location, height and shape, so that the final results obtained in the sunshine Fung Ka accurate and reliable.Compared with 2D sunlight analysis, imitating certain day's shadow changes in 3D scene is more precise and reliable. It can provide a quick and certain scientific analyzing method and accurate data foe urban plan departments, urban plan designers and citizens.At the end of the paper, the author introduces the method and the conclusion of sunlight analysis based on 3DGIS. For example, at the Siziwangqi, It can provide a certain and reliable result by this method,and analysis the results.