What do the ancients often mean by knowing astronomy above and geography below?

This word describes a wide range of knowledge and knows everything. Knowing astronomy above, geography below, harmony between people, yin and yang, gossip, mystery, hidden armor, strategizing, winning a battle thousands of miles away, comparing himself to a saint of Guanzhong Le Yi, sitting on his knees in a crisis, smiling and romantic, and before leaving the country, he made three points in the sky.

Astronomy refers to astronomy, including astronomical knowledge, astronomical calendar, the nature of various celestial bodies outside the earth's atmosphere and various phenomena-astronomical phenomena. Astronomy is always the forerunner of philosophy and always at the forefront of debate. Astronomy studies all kinds of celestial bodies in space, ranging from the moon, the sun, planets, stars, milky way, extragalactic galaxies and even the whole universe, to asteroids, meteoroids, and even large and small dust particles distributed in the vast space. Astronomers call all these objects celestial bodies. The earth is also a celestial body, but astronomy only studies the general properties of the earth and generally does not discuss its details. In addition, the motion properties of artificial aircraft such as satellites, spaceships and space stations also belong to the research scope of astronomy and can be called artificial celestial bodies.

Geography is a subject that studies various natural and human phenomena and their relationships in the geographical environment of the earth's surface. China's word "geography" first appeared in the Book of Changes. In English, the word geography comes from the Greek words H234G234 (meaning "the earth") and graphein (meaning "writing"). The earliest geography books in ancient China are Shangshu Gong Yu and Shan Hai Jing. Ancient geography mainly explores measurement methods related to the shape and size of the earth, or describes known regions and countries. Geography is very special, because there are both nature (natural geography) and humanities (human geography), so geography is a big science of the integration of arts and sciences.

"Knowing astronomy above, knowing geography below", because astronomy is the most profound and mysterious subject in the ancient concept, and it is also the subject most closely related to human daily life, full of admiration. This sentence means to praise those who are knowledgeable and versatile, not those who know astronomy and geography.