基于层次格网索引的图幅接边处等高线高程错误识别和自动修正研究

Research on Recognition and Auto-correction of Elevation Errors for Contours at the Edge of Map Sheets Based on Hierarchical Grid Index

等高线蕴含的历史高程信息可有效延长地形研究的时间序列,有利于深入挖掘地形变化长期规律,然而,图幅接边处的高程属性错误降低了等高线的数据质量,制约着等高线高程信息的实际应用。针对这一问题,该文提出一种基于层次格网索引的图幅接边处等高线高程错误识别和自动修正方法:首先,将层次格网索引与方向性二邻域算法相结合,以减少数据重复计算;然后,利用等高线空间位置标签及快速排序算法构建强空间位置关系,解决图幅接边处等高线匹配的准确性问题;最后,以高程冲突位点为驱动因子进行逻辑判断,实现等高线高程错误的识别及自动修正。实验结果表明:该方法运算效率较未进行效率优化时提高了203倍,接边处等高线高程错误识别与修正精度的最大值分别达97.71%和91.40%;相较于现有方法,该方法在精度和效率方面表现更佳,对区域性错误和变形等高线具有更高的适用性。

The historical elevation information contained in contours can effectively extend the time series of terrain study and facilitate the in-depth exploration of long-term patterns of terrain changes.However,the elevation errors at the edge of contour map sheets reduce the data quality of contours and restrict the practical application of contour elevation information.To address this problem,this paper proposes a method of recognition and auto-correction of elevation errors for contours at the edge of map sheets based on hierarchical grid index.Firstly,the hierarchical grid index and directional two-neighborhood algorithm are combined to reduce the data duplication.Secondly,the contour spatial location label and quick sort algorithm are used to construct the strong spatial position relationship to solve the accuracy problem of contour matching at the edge of map sheets.Finally,the elevation conflict site is used as a driving factor to make logical judgments on contours,thus enabling the recognition and correction of elevation errors.The results show that:the proposed method can effectively improve the operational efficiency,which is 203 times higher than that without efficiency optimization;logical error determination method can effectively recognize and correct contour elevation errors at the edge of map sheets,the maximum accuracy of recognition and correction reaches 97.71%and 91.40%respectively;compared with the existing methods,the proposed method has better performance in accuracy and efficiency,and has higher applicability to regional errors and distorted contours.