A pole-oriented discrete global grid system: Quaternary quadrangle mesh

In addition to providing services for mid and low latitudes, global Geographic Information System (GIS) should provide services for high latitudes; these services include climate monitoring, energy exploitation in the polar regions. An improved Discrete Global Grid System (DGGS) could serve as a foundation for efficient indexing, visualization and analysis of the ever-expanding global spatial data in the global GIS environment. However, existing DGGSs have problems with balancing polar and other regions, including serious cell area and shape distortion in the polar regions or precision loss when applying the systems to existing geographical data. Here, a new pole-oriented DGGS, the Quaternary Quadrangle Mesh (QQM), is proposed. This DGGS uses semi-hexagon (a type of quadrangle) grids in the polar regions and rectangular grids elsewhere. The semi-hexagonal partitioning in the polar regions reduces the redundancy of the polar data and avoids the polar singularities that frequently exists in DGGSs. A consistent encoding-decoding scheme and a uniform adjacent search algorithm were constructed by considering that polar cells and other cells form a coherent unity in the QQM, which has a hierarchical structure. The experimental results demonstrate that the QQM performs better than the recently proposed Degenerate Quadtree Grid (DQG) regarding geometrical distortion, and encoding-decoding and adjacent search efficiency. The QQM can satisfy the requirements for global data indexing and visualization, especially in the polar regions.