土地利用制图综合中的拓扑关系约束性规则

当前地图自动综合的理论与算法研究已经取得一定的进展,空间拓扑关系对制图综合起到重要的制约作用。土地利用图主要包含图斑、线状地物、零星地类3类图形要素,数据综合的工作量较大。本文结合土地利用现状图综合过程实践,基于点集拓扑交模型的理论与方法,讨论并分析如何根据图斑之间可能的拓扑关系(相离、点相接、外相邻、内相邻),结合语义等约束条件,选择合适的操作算子(如聚合、融合、退化等),抽象出土地利用图中图斑、线状地物综合前后存在的一些拓扑关系约束性规则。研究成果可作为土地利用制图综合前后的拓扑关系检查的一项依据,为综合算法的设计与实现提供一定的参考价值。后续的工作是:进一步完善该规则与算法,进行实验与应用。建议规则库与算法相分离,以保持各自的灵活性和独立性。

Topological Restrictions in Land-use Map Generalization

Land-use map generalization may cost much time for cartographers, so scientists constantly hope to find some methods automatically and have made a lot of efforts, but got few progresses. Right now, people main- ly focus on the theory and algorithms of generalization. In fact, the topological relation does great restriction dur- ing map generalization. Firstly, while beginning work, operation types of generalization may be chosen accord- ing to topological relations between the parcels and other limits （such as Land classification neighborhood）, e.g., they may be aggregated when they are adjacent, or amalgamated when disjointed, or reduce to points when inclu- sive. Moreover, based on the theory of point set topology and representation of Intersection Model, which is well known in GIS, we draw some topological rules from generalization of parcels and linear features of land-use map. E.g., when a long parcel （road or river） is generalized to be a linear feature, its neighboring parcels must be extended synchronously to make sure their topological relations unchangeable. Finally, the possible applications of these topological rules are discussed, as follows： These rules can be applied to check exactly the topological relationships between objects in land-use map before or after generalization, and used as the foundation of gener- alization algorithms. However, there still are many problems to be studied and improved in future work to make these rules more strictly. We also suggest making topological rule database apart from the algorithms, as rules are unalterable for some time while algorithms are various.