• 地球信息科学理论与方法 •

### 正六边形格网DEM下的等高线生成算法及质量评价

1. 武汉大学 资源与环境科学学院,武汉 430072
• 收稿日期:2021-07-17 修回日期:2021-08-13 出版日期:2022-04-25 发布日期:2022-06-25
• 通讯作者: *艾廷华（1969— ）,男,湖北宜昌人,博士,教授,主要从事空间数据挖掘,地图综合与尺度变换,可视分析。 E-mail: tinghuaai@whu.edu.cn
• 作者简介:肖 坤（1996— ）,男,河北沧州人,硕士生,主要从事地图综合、六边形DEM格网研究。E-mail: 2019202050048@whu.edu.cn
• 基金资助:
国家自然科学基金重点项目(41531180)

### Contour Generation Algorithm and Quality Evaluation of Regular Hexagon Grid DEM

XIAO Kun(), AI Tinghua*(), WANG Lu

1. College of Resources and Environmental Sciences, Wuhan University, Wuhan 430072, China
• Received:2021-07-17 Revised:2021-08-13 Online:2022-04-25 Published:2022-06-25
• Supported by:
Key Projects of National Natural Science Foundation of China National Natural Science Foundation of China(41531180)

Abstract:

Due to the advantages of isotropy, adjacency equivalence, and high fitting accuracy, regular hexagonal grid is used as the grid unit of regular grid DEM data structure and has been applied to digital terrain analysis such as flow direction analysis and valley line extraction. However, its quality detection and evaluation has not been well studied, and the quality of DEM directly affects the correctness and reliability of subsequent data analysis results and related decisions. Conventional methods such as checkpoint method and profile method can only evaluate the error of DEM locally, and cannot comprehensively evaluate the quality of DEM. Contour lines can reflect the overall situation of topography. Therefore, contour playback method is a relatively comprehensive and accurate method to evaluate the quality of DEM by analyzing the quality of playback contour lines and then detecting and evaluating the quality of DEM. Therefore, this paper applies the vertex height difference marking method to the grid structure of hexagonal DEM, proposes a contour generation algorithm for regular hexagonal grid DEM, and evaluates and analyzes the data quality of regular hexagonal grid DEM. Firstly, this paper uses three indexes: the topological correctness of the generated contour, the fit with the original contour, and the maintenance of bending features to evaluate the contour tracked by the vertex height difference marking method under the hexagonal grid structure. It has no topological errors such as self-intersection, fits well with the original contour, and maintains the bending features well, which proves the feasibility of the algorithm. In addition, this generation method is applied to the quality comparison of DEM with different regular grids, that is, the contour lines of quadrilateral DEM and hexagonal DEM are generated respectively based on the vertex height difference marking method, and the quality of contour lines generated by hexagonal DEM and quadrilateral DEM is compared based on the above three indexes, so as to compare the quality difference between hexagonal DEM and quadrilateral DEM. The experimental comparison shows that under the same resolution, the contour played back by hexagonal DEM has a higher fit with the original contour, and the bending feature is maintained better, and with the decrease of resolution, the decrease of fit is smaller, the loss of bending feature is less, there is no sharp angle, excessive shape deformation, etc. Therefore, the quality of hexagonal DEM is better than that of quadrilateral DEM, and with the decrease of resolution, the accuracy loss of hexagonal DEM is smaller.