Abstract :
Based on the classic data structure of quad-tree, topological cracks are created in the global terrain mesh in the adaptive subdivision case. A new topological structure called multi-resolution half-edges is applied for encoding multi-resolution mesh of the global terrain in this paper, which does not create topological cracks when subdividing the mesh adaptively. The main contents are as follows; Firstly, the theory of multi-resolution half-edges is introduced into the Spherical Diamond Grid (SDG), and some methods are put forward, including storage, encoding and coordinate transformation. Then, the adaptive seamless algorithm of SDG is designed and achieved. Finally, by using C++ language and DirectX tools, an experimental system is developed with the global terrain data, GTOPO30. The results show that the adaptive seamless model of the global terrain can be realized based on multi-resolution half-edges. Compared with restricted quad-tree, the simplified result based on multi-resolution half-edges structure is more efficient and complete in accordance with the terrain relief.
