postgis依赖很多其他包，下面一种方式能够下载所有依赖，完成pg的postgis安装

yum install -y https://download.postgresql.org/pub/repos/yum/reporpms/EL-7-x86_64/pgdg-redhat-repo-latest.noarch.rpm  

more pgdg-redhat-all.repo 

yum install epel-release -y

mkdir /root/yzg/

yum install --downloaddir=/root/yzg --downloadonly postgis23_10