IGeometry2.ProjectEx 方法中esriTransformDirection转换方向是什么意思？帮助中未找到相关详细说明。

参考下面链接：
http://resources.arcgis.com/en/help/arcobjects-net/conceptualhelp/index.html#//0001000009sw000000
里面说明：All methods supported by geotransformation are bi-directional; they can also be used to convert data from the target geographic coordinate system to the source geographic coordinate system.
这个参数向前还是向后都可以，因为其转换是双向的