相似变换在大比例尺地形图的投影换带中的应用

在大比例尺地形图的使用过程中，会遇地形图的坐标系变换，需要把中央子午线为L1的坐标系的地形图转换成中央子午线为L2的坐标系的地形图，称之为地形图投影变换。目前许多地形图是以电子地图形式存在的，是通过AUTOCAD软件形成的。基于此，本文提出了适用于AutoCAD中地形图投影换带的方法：相似变换法。即在满足精度要求的情况下，利用相似变换原理，对AutoCAD中的地形图进行平移，旋转，缩放变换，最终将其变换到需要的坐标系内。

The Application of Similar Transformation in the Map Projection Transformation of Large-scale Topographic Map

In the use of large-scale topographic map, the transfer of axes of Topographic Map is often encountered. One topographic map whose central meridian is L1 needs to be transferred to another topographic map whose central meridian is L2. This is called Projection Transformation of Topographic Map. But by far, the drawing and use of most relief-map was applied in the software of AUTOCAD. Basing on this, this paper will present a method for Projection Transformation of Topographic Map which was applicable to the AUTOCAD software. It is Similar Transformation. Namely, under meeting the required precision, using Similar Transformation principle, we can carry out the translations, circumrotation and zoom to the relief map in the software of AutoCAD, and finally translate it into the requested reference frame. This finishes the task of map projection transformation with less workload.