What are the contradictions and irrationalities in Zhou pian Ji Shu Jing?

What is puzzling is that the measured data of four trips to the North Pole in Zhou Bi suan Jing contradict the shadow length data of Yangcheng from winter to summer solstice. In addition, there is a clever explanation for the reasons why the sun appears and disappears in different solar terms, alternating day and night, and the length of day and night changes in four seasons, which reflects people's thinking and understanding level at that time, but there are many unreasonable points in studying its arguments carefully.