针对人工河网选取过程中需要考虑的几个重要因素，引入了线状要素动态分段模型组织人工河网数据及其空间知识。提出一种基于栅格的河网密度探测方法，较传统的计算网眼面积的方法简便且效果较好。建立了基于“知识决策”的人工河网选取模型，模型中考虑了复杂人工河网综合中河渠的属性（主要、次要）、长度、连通情况、河渠间的空间关系以及河网密度等5个方面的因素，建立多准则决策模型对每条备选河渠平等地进行综合评价，根据评价结果按照选取可能性从小到大间隔选取，从而能够较好保持人工河网的网络特征。

This paper analyzes the character of the complex canal network, and imports the dynamic segmentation theory to organize the canal network data and its spatial knowledge. A method based on grid to detect the network density is put forward and the result show it is better than other method. And also a canal network selection model is set up based on decision of spatial knowledge. This model integrates five factors of the canal selection such as the attribute, length, link condition, spatial relation between canals and network density. Then, utilizes the multiple criteria decision to evaluate each canal by these five factors, and make alternated selection to preserve the whole network character