A Study On The Digital Watershed Water System Building Based On Grid DEM

Digital Watershed Water System Building is one of the important aspects in the research field of digital hydrology. Water system building model of high quality can dramatically improve the effectiveness and accuracy of the application of the hydrological model and further guarantee the improvement of the precision of regional hydrology simulation.Based on geomorphologic features and the principle of distributed hydrological models, the globe approach and D8 algorithm were applied to define the framework of watershed water analysis in this thesis. In addition, the systematic structure of the watershed water analysis module was put forward according to the data flow in watershed water analysis and the data flow relationship in relevant algorithms.In this thesis, DEM data was classified with reference to the requirement of data in watershed water analysis. Moreover, the reason of various data formation and the corresponding relationship between those data forms and real geomorphologic features were discussed in detail.Based on the comparison among different DEM preprocessing algorithms on operation efficiency, a highly efficient and easily handled preprocessing algorithm was chosen to be the algorithm of processing depressions in this system.In this thesis, a VC++.NET computer program was applied to the design of watershed water analysis module, and several key problems were solved, such as the design function module structure, the selection of data organization mode, and the design of matrix searching algorithm. Moreover, information about the river network and the terrain feature of the watershed was also extracted by the virtue of the experimental data. The module successfully solved problems related with data processing and thus improved the operation efficiency.Results showed that the theory and the systematic structure put forward in this thesis as well as the design and realization of the module were of theoretical significance and had a splendid perspective for the research on the terrain feature extraction technology based on DEM.