基于QTM格网的空间数据无缝层次建模

A Hierachical Seamless Model of Spatial Data Based on QTM

以球面四元三角格网(QTM)为基本单元,构建了全球多分辨率空间数据的层次无缝表达模型.首先引入连续Quaternary编码作为QTM格网的索引,依照其编码规则,发展了该编码到经纬度坐标的转换算法;然后在不改变QTM格网层次特征的基础上,提出了基于顶点延伸的"缝隙"消除法;最后应用ArcGIS中的Wsiearth.tif图像数据和GTOPO30数据进行了相关实验,结果表明:该模型不仅保留了QTM格网的整体结构特征,且有效地解决了多分辨率空间数据表达时出现的"缝隙"问题.

A hierarchical seamless model for representing the global multi-resolution spatial data based on a quaternary triangular mesh （QTM） was constructed. The continuous quaternary code was used as index of QTMs and a transformation algorithm from quaternary code to longi- tude-latitude coordinates was developed based on its encoding rules. A vertex extension method of eliminating the cracks caused by different subdivisions was presented on the basis of not destroying the hierarchical characteristic of QTMs. The experiments and analysis are carried out with Wsiearth. tif image data in ArcGIS and GTOPO30 DEM data. The results show that the cracks in multi-resolution spatial data expression have been eliminated efficiently while the whole structure characteristic of QTM is maintained completely.