What is the relationship between Yuan Shoucheng and Yuan Tiangang?

Yuan Shoucheng is Yuan Tiangang's uncle. In The Journey to the West's literary works, Yuan Shoucheng is Yuan Tiangang's uncle and a famous warlock in the Tang Dynasty. He can know the past and the future and is good at judging yin and yang. Yuan Tiangang is a famous fortune teller, mathematician, astronomer and geographer in the history of China. His real identity is Yuan Hongdao, a great scholar in the Tang Dynasty. Yuan Tiangang was a famous warlock and prophet in the history of China, who lived in the Tang Dynasty. Known as the most famous Taoist in the Tang Dynasty, he is also one of the important figures in the history of Taoism in China. Yuan Tiangang's prediction and divination were very accurate, which won the appreciation and trust of Emperor Taizong and Wu Zetian. He once served as a member of the think tank of Emperor Taizong, making suggestions for Emperor Taizong, and also divining for Wu Zetian.