北京54测绘成果转西安80坐标系格网坐标改正数计算方法的研究

为了便于湖北省全国第二次土地调查中北京54与西安80坐标系之间的转换,湖北省测绘局提供了基于1∶1万图幅的北京54转西安80图廓格网坐标改正数,供各测绘单位对其成果进行转换。考虑到各测绘单位对精度上的要求不同,湖北省测绘局并没有提供具体的转换方法。基于平面相似变换和仿射线性变换原理提出两种格网坐标计算方法,并对其转换精度进行分析,得出有益的结论。由于该方法不涉及外业公共点的选取和测量,因此具有非常重要的实用意义,可供相关测绘部门进行测绘成果转换。

Calculation of Turbulent Flow with Pseudo-spectral Method

This paper deals with the numerical simulation of incompressible turbulent boundary flow of a flat plate with the pseudo-spectral matrix method. In order to appear more than 10 nodes in the turbulent base-stratum and transition of 43×43 computational grids,a coordinate transformation is put up from physical panel to computational panel. Several zero turbulent models are computed comparatively. The results are credible when comparing with the previous methods.