DEM (GTOPO30) と DCW を用いた落水線図作成アルゴリズムの開発

抄録

Drainage Direction Matrix (DDM) which can be generated from Digital Elevation Model (DEM) is useful information in order to analyze environment of watersheds. There are many studies about algorithm to make DDM from DEM, however, verification and modification, those are required to fit the river systems in the real world, are not easy. In this paper, algorithm for generating DDM using both DEM and existing river system map is proposed. By using the algorithm, the shapes of computed derived river system are similar with those of existing map information, if the streams information as input data are clearly delineated and prepared. As an application of the algorithm, continental scale DDM covering East Asia was generated using GOTPO30 and DCW with 30 seconds mesh size. There still require many corrections to have a perfect DDM because of difficulties to prepare perfect input data, however, the procedure to correct the errors is clear and easy to undertake.