道路网自动选取是自动制图综合中的难点和重点工作之一，已有的自动选取方法在选取过程中没有将全图的道路网作为一个整体来考虑，道路网结构特征保持不明显。通过一系列的实验，利用图论的不同方法对道路网进行自动选取，并对结果进行了分析和比较，构造出了一种较好的道路网自动选取方法。根据平面图形的网络特征将道路网分为两种类型（乡村型和城市型），并针对每种类型的道路网提出了不同的选取方法。实验结果表明，选取效果较好，能够满足道路网自动制图综合的需要。

Road networks’ auto selecting is important but difficult in auto generalization. All roads in the map have’t been regarded as whole in present selecting methods. So the characteristic of road networks can’t be kept. A series of experiments have been done that road networks have been auto selected by different methods using graph theory. The results have been analyzed and compared, and then a better method has been proposed for road selecting. Through these experiments, the effect is better and it fits the necessity of road networks auto generalization.