题目

英语翻译
Accurate error estimates can be calculated with at least 4 GCPs,while often at least 5 are needed to cover the center of the project as well,which reduces the chance of error propagation and resulting terrain distortions especially on flat or undulating terrain types.

提问时间：2020-08-16

答案

用至少4个地面控制点可以计算出准确的误差估计,而通常至少需要5个地面控制点以同时覆盖项目的中心区域,这样可减少误差传播从而导致地形失真的几率,尤其是在平坦或起伏的地形类型上.