Study on measurement and evaluation of land transformation using photogramtry and GIS

至于日本近年的地震灾害，郊区的屋苑也受到影响。这些庄园是通过土地改造在丘陵地带开发的，在山谷中填充，在山脊上切割。本研究的目的是利用摄影测量和地理信息系统，测量土地的变化，并评估土地的土地条件，以防止地震。通过对改造前后土地DEM的制作、GIS中土地状况指数的形成、多变量分析等一系列分析，探讨了房屋损坏与土地状况之间的关系，在无法获得大比例尺地形图的情况下，可以利用航空照片获取改造前的DEM。但初步研究表明，利用数字摄影测量技术直接生成DEM难以获得高精度的DEM。在此基础上，对钏路、科比和福冈3个城市改造后的土地进行了房屋破坏分析。通过正交表和Logistic回归分析，分析了各案例震害（建筑物震害）空间分布与各种土地条件指标之间的关系，认为“填土厚度”和“离填挖分界线的距离”是影响建筑物震害的重要土地条件。此外，案例研究的结果进行检查，以预测未来的损害在改造的土地。研究期间还对2003年发生的北方宫城地震的震害进行了调查和考虑。

As for the earthquake disaster in recent years in Japan, housing estates in the suburban area have been affected. These estates were developed in the hills by land transformation with fills in the valleys and cuts on the ridges. The purpose of this study is to measure the land transformation and to evaluate the land conditions of the land against earthquake, using photographic surveying and GIS. A series of analyses is developed from the preparation of the DEMs of the land before and after transformation, through formation of the land condition indices in GIS, to multivariate analysis to discuss the relationship between the housing damage and land conditions.In the case that large scale topographical maps are not available to obtain the DEM before land transformation, air photographs may be available. However, it was proved that direct DEM formation by digital photogrametry technology was difficult to obtain the DEM precisely by the pilot study. Instead, the DEM was obtained by a series of techniques : air photographs → stereoplotting contours → digitize the contours → DEM formation in GIS.Housing damages in the transformed land in Kushiro, Kobe and Fukuoka were analyzed by the series of the techniques. The relationship between the spatial distribution of earthquake damage (building damage) of each case and the various land condition indices were analyzed by the cross tabulation and logistic regression analysis.As a result, "thickness of fills" and "distance from cut-fill boundary line" were recognized influencing building damage as significant land conditions. Furthermore, the results of the cases studies are examined in order to predict future damage in the transformed land. The damage of Northern Miyagi earthquake which occurred in 2003 in the study period were investigated and considered, as well.