基于网眼密度的道路选取方法

道路数据中的网眼密度能反映局部区域的道路密集程度,通过确定目标尺度要求的密度阈值,比例尺缩小后能够标识出数据中需要取舍路段的网眼;循环剥离密度最大的网眼,利用反映路段重要性的参数及其优先级,渐进筛选出舍弃的路段,并完成与邻接网眼的合并;得到的选取结果保持了道路网在密度、拓扑、几何及语义方面的重要特征,从而提出一种新的道路选取方法。最后进行实验,验证该方法的有效性。

Selective Omission of Road Features Based on Mesh Density for Digital Map Generalization

Selection of roads is an intractability generalization operation,due to the difficulty in retaining the density difference and connectivity of a road network.This paper proposes a new approach of selective omission for roads based on meshes density.Density of roads is calculated using meshes as units and represents local region density in a network.Usually,the density is different between maps with different scales.The density thresholds are acquired by theoretical analysis and empirical study for mesh density on different scale maps.For meshes with density over threshold,the largest density meshes are taken out by turns and one road segment of them is eliminated.Meanwhile the taken mesh is merged with the adjacent mesh at a time.Road segment to be eliminated is the most unimportant in all segments on the boundary of this mesh according to the parameters reflecting the importance of road segments.In this study,the meshes are classed depending on the types of road segment.For the different type meshes,their thresholds are different,which can preserve the density difference.The process of eliminating road segments and merging meshes would ensure the road network connectivity.This proposed approach considers topological,geometric and semantic properties of the road network.A road network is selective eliminated employing this approach,and the results of selection achieve better effects.