层次化等深线簇的深度注记配置方法

A method for placing cartographic annotation of depth values based on hierarchical depth contour cluster

针对当前等深线深度注记自动配置方法未考虑等深线走势导致配置结果整体不协调、分布不合理的问题,提出一种利用树状结构层次化等深线簇的深度注记自动配置方法。首先采用树状结构,建立起海图上各条等深线间的空间关系;然后通过等间隔布设等深线簇的注记定位线、求取线段交点,生成多个备选的注记配置方案;最后以每个备选方案的平均弯曲度为指标,评价注记位置等深线的平缓程度,优选出注记位置最平缓的配置方案。实验结果表明:所提方法能够顾及海底地形变化特征和等深线走势,注记配置结果在整体的协调性、分布的合理性上优于MapGIS自动配置的注记。

Aiming at the drawbacks that the cartographic annotation of depth values in depth contours are overall uncoordinated and unreasonable distributed due to the current methods for placing cartographic annotation of depth values in depth contours do not consider the trend of depth contour,a method for placing cartographic annotation of depth values is proposed on a basis of hierarchical depth contour cluster.Firstly,the tree structure is constructed for grasping the spatial relationship of the depth contour lines on the chart.Then,several alternative schemes are generated for placing cartographic annotation,by laying the annotation positioning line of the depth contour cluster at equal intervals and obtaining the intersection point of the line segment.Finally,the average curvature of annotations is adopted for evaluating the quality of the scheme,and the optimal scheme is chosen.The experimental results show that the proposed method can take into account the characteristics of the topographic seabed and the trend of depth contours.The results of annotation configuration are more coordinated and reasonably distributed than those of MapGIS automatic configuration.