Abstract
This paper proposes an analysis and evaluation method for the openspace planning, based on the watershed unit and the common data. We studied on a scale of 1 : 2,500, the basic scale of the city planning. The common data means the spatial information that is digitally available. Using the GIS, we defined small watershed units in Yokohama city in a formalized manner and created a database that shows the qualities and quantities of openspaces and the geographical character of each small watershed. For the common data, we used the digital map 50m grid (elevation) (50mDEM) . Small watersheds were further classified into several groups by the ratio of forest and farmland to analyze the environment of green open spaces of the small watershed unit in the upper stream of the Katabira river. Our method gives a comprehensive view of the openspace planning and facilitates the understanding of the characteristics of the urban fringe areas, where the conflict between urban developments and the natural conservation exists.
