Abstract
Automated map generalization is an inevitable trend, however, most current research mainly focuses on technical aspects. Particularly for the hydrologic network, it is an extremely important factor on the map and is easily affected by scale changes in different ranges. Therefore, the selection and simplification needs to be based on the distribution characteristics and linking to avoid loss of important information. This study proposes a solution to classify, determine hierarchy and assign priority values to hydrologic elements. Specifically, based on the directed "tree" structure of the network to identify "parent-child" relationships and establish priorities. Next, use a hierarchical elimination algorithm to facilitate the selection of elements and remain with them, according to the target map scale. Finally, use the proportional hierarchy removal algorithm, use test sample data in Thanh Hoa District, Long An province and evaluate the results.