Hierarchical relationship construction and simplification method of tree-shaped river system of stroke feature constraints

Abstract

The invention discloses a hierarchical relationship construction and simplification method of a tree-shaped river system of stroke feature constraints. A directed topology tree (DTT) of the tree-shaped river system containing semantic features, geometric features and topological features is established according to an organization mode of the tree-shaped river system in an actual spatial database; and then the semantic and geometric features and the topological features of stroke objects are synthesized, starting from an estuary, tracking from lower reaches to upper reaches is adopted to construct the tree-shaped river system of the stroke feature constraints, structural features including river spacing and river network density are automatically identified according to the tree-shaped river system of the stroke feature constraints, and automatic simplification of the tree-shaped river system is realized according to a simplification method of hierarchical relationships of the river system. According to the method, artificial operations are simplified, the degree of automation is high, the spatial distribution features of the river system can be effectively and intelligently identified, the accuracy rate is increased, and the precision is improved. The method has a good effect in an aspect of maintaining an overall spatial distribution structure of the river system, and guarantees retaining a basic outline of the river system by a graph after simplification.

Description

technical field [0001] The invention relates to the field of map drawing and map synthesis, in particular to a method for constructing and simplifying tree-shaped river system hierarchical relations constrained by stroke features. Background technique [0002] River system describes the network connectivity and distribution of natural rivers, is one of the main basic geographic information elements, and is an indispensable skeleton in map expression. River systems usually include dendritic, grid-like, and feather-like types. Among them, tree-like river systems have obvious hierarchical structure and density characteristics. The mainstream and tributaries contain a "parent-child relationship" in space. There are also regional differences. Therefore, when comprehensively selecting tree-like river systems, it is necessary to keep these main rivers, and to reflect the spatial structure characteristics of the river system and the density difference of the river network. In the a...

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Problems solved by technology

Wu Hehai studied the establishment method of the river system tree structure earlier, and proposed a tree structure model of the recursive characteristics of the river system, but the main stream still relies on length identification or manual designation; Guo Qingsheng et al. Using the method of spatial reasoning to determine the flow direction and the hierarchical relationship between main and tributary streams enriches and expands the scope of application of the "180° hypothesis" and "acute angle hypothesis". The processing of some links in the tree has not formed a complete solution; Zhang Yuanyu et al. combined the structural characteristics of the tree-like river system itself and the idea of ​​​​graph theory, and proposed a river system structure model based on graph theory. Although the manual operation is simplified, the degree of automation still lacking

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