中文摘要：

提出了先确定边界、再逐步精化的研究思路，系统、直观地阐述了投影的基本原理，并推导了严密的变换公式，在此基础上给出了详细算法和部分实验结果。

英文摘要：

A method is introduced that begins with the confirmation of the projection boundaries. The projection theory is described systematically and the strict transform formulas are given step by step,and forward and inverse algorithms of SEA projection are designed.