So,a model of the discrete network design problem(DNDP)based on the transformable network units is built by introducing the network generation arithmetic operator(NGAO)in.

• 进而建立了基于可变网元的离散路网设计模型,采用路网生成算子来表征道路增减带来的路网单元结构的变化,设计了路网生成算子的算法流程。