Skeleton line extraction for areal hydrographic elements considering spatial and hierarchical relationships

Abstract

This study focuses on a skeleton line extraction algorithm of areal hydrographic elements for cartographic generalization. The requirements of skeleton line extraction for areal hydrographic elements were first analysed and a new automatic extraction algorithm that considered spatial and hierarchical relationships was proposed to meet these requirements. A graph with structured areal hydrographic elements was subsequently presented, and the graph pruning operation was conducted based on the spatial relationship and pruning length threshold. The skeleton line connection of the traditional unconstrained edge midpoint algorithm was improved by the guidance of spatial and hierarchical relationships. Finally, the proposed method was used to extract skeleton lines from 1:250,000 hydrographic elements, and compared with other algorithms. The experiments demonstrate that the skeleton lines extracted by the proposed method have certain advantages in natural continuity, hierarchy, and topological consistency; the results are closer to those of manual extraction and avoiding the subsequent optimization process.

Keywords:

• Cartographic generalization
• areal hydrographic element
• skeleton line extraction
• skeleton graph

Acknowledgements

This work was supported by the National Natural Science Foundation of China under Grant [number 42101454, 42101455]; the Fund Project of ZhongYuan Scholar of Henan Province of China under Grant [number 202101510001]; Joint Fund of Collaborative Innovation Center of Geo-Information Technology for Smart Central Plains, Henan Province and Key Laboratory of Spatiotemporal Perception and Intelligent processing, Ministry of Natural Resources under Grant [number 212102].

Disclosure statement

No potential conflict of interest was reported by the authors.

Data availability statement

Data and code are available from the corresponding author by request.