Channel Network Tool-I的原理与功能

Principium and Function of Channel Network Tool-I

CNT-Ⅰ(ChannelNetworkTool-Ⅰ)是基于复合信息(数字高程模型和栅格化主干河网)自动提取流域地表水文特征的专用软件包。它利用主干河网的位置信息指导D8法单元网格水流模式的提取,弥补了现有工具软件使用的数据源单一带来的问题和不足,在平原区和洼地的处理上有了很大改善。CNT-Ⅰ专门针对配置一般的计算机设计,支持千万格点以上的各种分辨率的栅格数据,并内嵌了分辨率为30″的中国大陆DEM和相应的Ⅰ、Ⅱ级主干河网,且能以30″的整数倍输出任意区域的河网、流域边界、准三维渲染图,以及栅格的流向、坡度、汇流路径等数据,并能根据用户的要求度身定制,具有很强的实用性。介绍了该软件的原理和功能,并与同类型的商业软件进行了比较。

CNT-I Channel Network Tool-I is the first and exclusive software to automatically determine catchment properties based on the binary message from DEM Digital Elevation Models combined with RRN Raster River Network while other tools only use DEM data. This new tool can overcome DEM's inherent fault and getting a more emulation drainage structure by adding new kind of message so that the problems of parallel line in plat area and transaction of depression can be solved to a certain extent because the RRN can not only transfixion parts of the pit and plat area but also lead the flow direction of vicinal cells. More credible catchment properties are sure is obtained from it. This new principium used in CNT-I have three steps. Firstly cells relevant to natural river are selected and linked with direction with two particular methods named Headstream Seek Model and Deep First Model. In order to avoid the disturbance from 'data noise' that means some local cells' value fluctuating unnaturally and deviating from actual synthetically analysis is used in these two models. Secondly the other cells are transacted expanding from these determined cells and a drainage structure is getting. With the controlling of river network's message the drainage structure is closer to actual river. Thirdly catchment properties could be obtained such as area and boundary of subbasin gradient between cells and so on.CNT-I is designed for common user and could finish several million cells data rapidly. Having been equipped with DEM and RRN of Chinese mainland with cell size of 30″ it could give results of any integral times of this size and customized for special needed. Two years serious inspection in different departments and affairs shows its powerful practicability and large improved precision.