基于遥感影像的城市空间三维绿量(绿化三维量)定量研究

Remote sensing image-based quantitative study on urban spatial 3D Green Quantity Virescence three-dimension quantity

三维绿量又称绿化三维量 ,是指所有生长植物的茎叶所占据的空间体积。城市三维绿量的测量研究是城市绿化环境效益评价的基本前提 ,也是城市生态系统研究的重要内容之一。以彩红外航空遥感图像为主要信息源 ,研究了城市空间三维绿量定量计算的方法。在对植被遥感阴影图像分割的前提下 ,根据航空摄影时太阳、摄影机以及树木三者之间的几何位置关系 ,建立了空间三维绿量遥感中关键的植被高度模型。应用统计分析方法 ,建立了研究区主要树种的树高 -冠径相关关系模型。根据冠径 -冠高关系以及典型树种的树冠立体几何形态与绿量方程 ,运用 GIS分别计算了浙江省宁波市江北区、江东区、海曙区和全市的总三维绿量和平均相对三维绿量 ,以及平均相对三维绿量的区域分布。宁波市全市及江北区、海曙区和江东区的平均相对三维绿量分别为 32 84 .4 m3/hm2 、36 5 2 .4 m3/hm2 、2 90 8.5 m3/hm2 和 32 2 9.7m3/hm2 ,总三维绿量分别为 16 0 6 .6万 m3、6 5 9.5万 m3、4 4 8.9万 m3和 4 98.2万 m3。研究结果不仅为城市绿化数据库的建立奠定了基础 ,而且还丰富了城市绿化评价指标 ,有助于估算城市绿化的生态环境效益 ,以及为城市绿化系统的设计 ,特别是为环境要求不同的功能区的绿化系统的设计、城市绿化群落布局的合理性?

Three-dimension green quantity, also named virescence three-dimension quantity,refers to the spatial volume formed by stem and leaf of a plant. The study of the measurement for three-dimension green quantity is a basis precondition for the estimation of virescence urban environmental benefit, and also is an important part for urban ecosystem study. The present paper purports to take the color infrared aerial remote sensing image as its main research data. The basic method of quantitative remote sensing is investigated for urban spatial 3D green quantity. Firstly, the image's shadow of a plant is segmented. Secondly, the height model of a tree is established in accordance with the relationship of the sun, the camera and the tree in aerial remote sensing, which is a key model in spatial 3D green quantity. Thirdly, the model of relationship a tree's height and diameter for the crown of a tree, and the model of the relationship between diameter and height for the crown of a tree, are established by the statistic method, as correlativity of height with diameter for the crown of a tree exists specifically for the species of a plant. Fourthly, the stereoscopic geometry form and green quantity equation are established based on the study of the stereoscopic geometry form for typical species of a tree. Finally, the total 3D green quantity, the average relative 3D green quantity and its distribution are calculated GIS-based. The value of average relatively 3D green quantity is 3284.4m^3/hm^2, 3652.4m^3/hm^2, 2908.5m^3/hm^2 and 3229.7m^3/hm^2,and the value of total 3D green quantity is 1606.6×10~4m^3, 659.5×10~4m^3, 448.9×10~4m^3 and 498.2×10~4m^3 in Ningbo city, Jiangbei district, Jiangdong district and Haishu district of Ningbo City. The results indicate that there is correlativity between the average relative 3D green quantity and the rate of green overlay in these regions. The average relative 3D green quantity will be large, if there is a big coverage rate of green overlay in a particular area. But the linear correlativity dose not exist among them, for the factors, which affect the average relative 3D green quantity include not only the coverage rate of green overlay, but also the structure of virescence and growth state of plant. The method not only is important for the establishment of a city's green database, but also provides an important index for the evaluation of urban green area and is useful for studying of the green environmental benefit. At the same time, the findings of the study will also provide useful parameters for the design of green systems, especially to design for regions with special demands of green regions, and rationality for urban green community distribution and urban green planning.