Journal of Geo-information Science >
The Accuracy Control in the Process of Vector Line Data Drawing in the Hexagon Discrete Global Grid System
Received date: 2014-12-31
Request revised date: 2015-03-26
Online published: 2015-07-08
Copyright
The Discrete Global Grid System (DGGS) is a new type of global spatial data model and is the extension of the plane grid on a sphere. Hexagon is usually used in the construction of DGGS for its advantageous geometric structure. Since sphere is unextended, in the process of plane grid mapping, the distance and direction of the grid will change greatly. As a result, the accuracy of drawing vector data in the global grid cannot be guaranteed. This has been a critical choke point for the display of vector data in DGGS and has directly restricted the establishment of spatial measurement relationship on a spherical grid. In order to solve the drawing problems of vector line data in hexagon DGGS, this paper has studied the distortion regularity that the plane-sphere mapping process affects the linear direction, and control the accuracy of vector line data grid transformation. As a result, the vector drawing method on a plane grid can also be adopted to deal with high-accuracy drawing on a spherical grid, and it guarantees that the spherical grid drawing errors of the vector data can be controlled strictly in one cell of the current layer´s grid. This paper also lays the theoretical foundation for high-accuracy display of grid transformation data and the establishment of spherical grid spatial measurement.
YU Wenshuai , TONG Xiaochong , BEN Jin , XIE Jinhua . The Accuracy Control in the Process of Vector Line Data Drawing in the Hexagon Discrete Global Grid System[J]. Journal of Geo-information Science, 2015 , 17(7) : 804 -809 . DOI: 10.3724/SP.J.1047.2015.00804
Fig. 1 The deformation of vector line between spherical grid and plane grid图1 球面平面差异带来的格网矢量线变形 |
Fig. 2 Three directions of lines arranged by hexagon grids on icosahedron triangular facet图2 二十面体三角面上格网排列成直线的3个方向 |
Fig. 3 The approach of calculating spherical line distortion using projection method图3 利用投影法计算球面直线变形的方式 |
Fig. 4 The contorted situation of spherical line using Snyder projection图4 利用Snyder投影法计算球面直线的变形 |
Tab. 1 The average area, average radius and average curvature error of cells on discrete global grid表1 |
层数 | 面积() | 平均半径() | 平均曲率误差() |
---|---|---|---|
2 | 5 544 191.6145 | 1460.8081 | 169 735.3625 |
3 | 1 409 021.0733 | 736.4323 | 42 705.6680 |
4 | 353 720.9629 | 368.9814 | 10 693.8838 |
5 | 88 522.3236 | 184.5867 | 2674.5702 |
6 | 22 136.3436 | 92.3054 | 668.7114 |
7 | 5534.4462 | 46.1542 | 167.1821 |
8 | 1383.6341 | 23.0773 | 41.7958 |
9 | 345.9099 | 11.5387 | 10.4490 |
10 | 86.4776 | 5.7693 | 2.6122 |
11 | 21.6194 | 2.8847 | 0.6531 |
12 | 5.4048 | 1.4423 | 0.1633 |
13 | 1.3512 | 0.7212 | 0.0408 |
14 | 0.3378 | 0.3606 | 0.0102 |
…… | …… | …… | …… |
Fig. 5 The generation effect of vector data on the hexagonal discrete global grid system图5 全球六边形离散格网上矢量数据的生成效果 |
The authors have declared that no competing interests exist.
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