Abstract
In Tokyo Ward area, 137 refuge bases are designated for urban disaster prevention. Though refuge bases that have effective area of less than two square meters for each refugee or distant refuge bases are exist, shown in Fig.2(a) and Fig.2(b). This paper describes methods of finding open spaces which are possible to be refuge bases in Tokyo Ward area by using TM (Thematic Mapper) data taken on November 4, 1984 acquired from LANDSAT-5. The process of estimating an effective area is shown as follows : STEP 1 : decide the constituent element of the effective area (trees, grass land, lawn land, bare land, concrete pavement and high-rise building which occupies a refuge base more than 15 %). STEP 2 : estimate the percentage of an effective area using percentage of land-cover categories construct an effective area, percentage of low-rise bldg. area within 100 m in circumference, sum of percentage of high-rise bldg. area, middle-rise bldg. area and water, on the boundaries. STEP 3 : calculate an effective area As a result, the following equation can be constructed : Y=0.16 X_1-1.49 X_2-0.19 X_3+85.69 where : Y=estimated percentage of an effective area -% X_1=percentage of land-cover categories construct an effective area -% X_2=percentage of low-rise bldg. area within 100 m in circumference -% X_3=sum of percentage of high-rise bldg. area, middle-rise bldg. area and water, on the boundaries -% We select newly site proposed for refuge bases (Fig.11). The results show that possibility and effectiveness using remote sensing as one of the data base for urban disaster prevention.
