Fast Translating Algorithm between QTM Code and Longitude/Latitude Coordination
Fast Translating Algorithm between QTM Code and Longitude/Latitude Coordination
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发表时间：
2003
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通讯作者：
Zhao Xue
中科院分区：
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作者：
Zhao Xue
球面四元三角网格结构是管理全球海量地球数据的有效方法。但现有的QTM码与经纬度坐标之间的转换方法存在着转换速度慢或编码缺乏针对性等问题。为了克服这一严重缺陷，提出了一种新的翻译方法-该方法的原理是基于QTM的行和列，按一定方向递归逼近地址码。给出了新算法的具体实现步骤。通过实验分析了不同层次上不同点数的翻译方法。结果表明，CAM方法不仅能在一定方向上产生地址码，而且时间消耗仅为ETP方法的7%~20%。
QTM (Quarternary Triangular Mesh) structure on spherical surface is an efficient method in managing the global large quantities of the earth data. But the existed translating methods between QTM Code and Longitude/Latitude Coordination have low efficiency in translating speed or lack of certain orientation in encoding. To overcome this serious deficiency, a new translation method——CAM (Cavalcade Approach Method) is presented. The principle of this method is based on the Row and Column of QTM and recursively approach the address codes according to certain orientation. Detailed steps of new algorithm are also presented. Different translating methods are analyzed in experiment by using different number of points in different levels. The result indicates that in CAM method not only the address code is generated in certain orientation but also time consumption is only about 7%～20% of ETP (EqualTriangles Projection) method.