Development of Numerical Technique for Urban Landscape Assessment by Computer Calculation

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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.