Extraction Of Digital Drainage Network Characteristics Base On Standard Template Library

Extraction of digital drainage network from DEM(Digital Elevation Models) is the base of distribution hydrological model. The source of DEM are various. This paper discusses the prevalent DEM data source-SRTM DEM's characteristic and applies SRTM data to hydrology science using River Tools and ArcGIS Hydro Tools software with the aim of testifying the validity of SRTM data in hydrology. SRTM DEM has a higher resolution, precision and available in broad scope than GTOPO DEM data.This paper reviewed the algorithm of extracting watershed network. Comparing the main pre-method to fill sinks of DEM and each algorithm's time complexity. A new method is used to develop a system. The algorithm is based on a novel concept of spill elevation and integrating the priority queue data structure into the least-cost search algorithm progressively to determine the spill elevation of every grid. The final DEM data after such a processing procedure are the elevation data without depressions. It is not only simple to understand but also faster than the other algorithm in processing the different sizes and resolutions of DEMs. With the support of the library "tree.hh", the program is simple and compact. Finally, the software is testified with SRTM DEM data and other DEMs with 30s resolution in several drainage area. The river network generated from the software is accord with actual river.The system was analyzed and designed with object oriented analysis and design method. The language using in this system is C++ with the support of STL (Standard Template Library) and is compiled in VC++. NET2003. STL, which has a new characteristic called namespace, is a general name of container and algorithm in Standard Library. Its aim is not only to combine different algorithm and data structure but also to get great efficiency. Program based on STL has a compact procedure and is easy to comprehend. With the method of building tree data structure to finish the system, it is easy to identify the watershed boundary and calculate the flow direction of every grid in DEM as well as extract subcatchment with the specified point. The system has little influence with actual terrain land and could apply in plain and...