墨卡托投影

UTM投影和Gauss-Krüger投影及其变换实现

自定义坐标系的建立及其坐标变换实现

你常用的海图是这样的

Transverse Mercator projection

Universal Transverse Mercator coordinate system

https://en.wikipedia.org/wiki/Helmert_transformation

http://webhelp.esri.com/arcgisdesktop/9.3/datainterop/mergedProjects/FME_Workbench/geodetictransform/bursa_wolf_transformation.htm

ppm

Helmert.java