Because the elevation data we have acquired through gps is too variable to satisfy the mapping accuracy requirement the elevation value is solved by the water lever observation in the hydrology station and datum horizon correction of sounding observation 由于gps的rtk模式测量所获取的高程精度不能满足测图精度要求，因此其高程值是通过测量水深值、结合其统一到基准面的改正数、根据相关水文部门各水位站提供的水位观测资料综合计算获得。
