datum transformation的用法和样例：
例句
- The unitary iris image is carried out through the transformation from Cartesian coordinates to polar coordinates.
然后采用极坐标转换对虹膜图像进行归一化。 - This paper presents calculation method and coordinate transformation relation in detail, which can be used in similar project design directly and reduce design work greatly.
对计算方法和坐标转换关系作了详细介绍，可直接运用于类似工程设计，从而使设计工作量大为减少。
