Development of Numerical Technique for Urban Landscape Assessment by Computer Calculation

这项研究是关于城市景观评价的计算机数学技术的发展，包括程序。一位大师有两个主题，第一个主题是京都东山天际线的能见度分析，第二个主题是利用城市地区自然景观的摄影图像和日本地理测绘研究所出版的数字地图数据(50m栅格高程)产生的三维模型来选择区域。这里的独特之处在于系统的开发，包括计算机图形学中的消隐技术(Z缓冲法)。接下来介绍了针对第一个问题的处理流程。(1)在任何人都可以进入的道路上产生许多视点。(2)建筑物--用于三维图形的模型是若干个类似于构成城镇街区的墙的多边形。(3)利用CG的Z-Buffer算法计算山体天际线的能见度。(4)在图中画出计算结果，便于理解。第二个问题的处理过程如下。(1)制作照片的数字图像，例如，京都东山的景色。(2)实现了基于数字地图数据(格网高程50m)的地物三维模型。(3)利用三维CCG软件生成同一视点的透视图像。(4)将山体表面的面积叠加到(1)S图像的同一轮廓区域上进行成像。(5)计算生成与前一透视图像相同的透视图像，同时利用基于CG的Z-Buffer方法提取可见区域。(6)在地图上绘制选定区域。将个人计算机、工作站、数码相机、数字化仪器和扫描仪结合在一起，制作了一个系统，并使用市面上的软件和自己的工作软件。

This study is about development of mathematical technique by computer for the urban landscape evaluation including program. A master has 2 theme, and the first theme is visibility analysis of skyline of Higashiyama in Kyoto, and the second theme is selection of the area by using photographic image of natural landscape viewing through an urban area and 3-D model that is produced from "Digital map data (50 m grid elevation)" published by Geographic Strrvey Institute of Japan. Here is peculiar in the point which contains the system development including hiden-surface elimination technique (Z buffer method) of computer graphics (CG).The flow of the treatment toward the first problem is stated next. (1) Many view points are caused on the road which anyone can enter. (2) Buildings- model for 3D graphics is several polygons which is similar to wall that compose town-block. (3) Visibility ratio of mountain skyline is computed by Z-buffer algorithm of CG. (4) A calculation result is drawn in the figure to make it easy to be understood.The treatment process of the second problem is like this. (1) Make digital image of photograph, for example, view of Higashiyama, or Eastern Mountains, in Kyoto. (2) Accomplish 3-D model of the geographical features that is based on digital map data (50 m grid elevation). (3) Produce the perspective image from same viewing point by software of 3-D CCG. (4) Make image by overlaing area of mountain surface on same outline area of (1)'s image. (5) Calculate for making image of perspective view as same as previous perspective image, at that time exacting visible area by the technique that is based on Z-buffer method of CG. (6) Draw selected area on a map.Personal computer, workstation, digital-camera, digitizer and scanner were combined, and a system was made, and software on the market and the software of the own work were used by this research.