最小二乘法擬合圓
https://blog.csdn.net/liyuanbhu/article/details/50889951
圓上三點求圓心和半徑
https://blog.csdn.net/lijiayu2015/article/details/52541730
三點確定一個圓的計算方法
https://blog.csdn.net/liyuanbhu/article/details/52891868
https://blog.csdn.net/liyuanbhu/article/details/50889951
https://blog.csdn.net/lijiayu2015/article/details/52541730
https://blog.csdn.net/liyuanbhu/article/details/52891868
shell腳本獲取腳本所在目錄 執行腳本的父目錄不一定是當前的工作目錄。 url=$(dirname $(readlink -f $0))