此文章说明在高斯投影下子午线收敛角计算方法-This article shows the Gaussian projection method under the meridian convergence

高斯投影正算源代码 实现经纬度BL到大地坐标XY的正算过程，并计算子午线收敛角-Gauss projection is considered the source code to achieve BL latitude and longitude to XY coordinates of the earth is the counting procedure, and calculate the radial convergence angle