We know that the sun moves from east to west, while the shadow moves from west to east. For example, at 6 o'clock in the morning, the sun rises in the east, and the shadows of all objects fall to the west; By noon 12, the sun is due south and the shadow points to the north; At 6 o'clock in the afternoon, the sun is due to the west and the shadow points to the east. Therefore, the direction can be roughly determined by the shadows of the sun and objects.
As the saying goes: "immediate", use a pole (straight pole) to make it perpendicular to the ground, and put a stone at the vertex A of the pole shadow; About 10 minute, when the shadow vertex of the column moves to B, put another stone to connect the two points A and B into a straight line, which points to the east-west direction, with the direction perpendicular to the AB line as the north-south direction, the end facing the sun as the south, and the opposite direction as the north (Figure 5).
According to this method, the higher the pole, the thinner it is, and the more perpendicular it is to the ground. The longer the shadow moves, the more accurate the direction is, especially around noon 12. For example, the shadow lengths at 1 1.30 and 12.30 are almost equal, and the connecting line of vertices just points to the east-west direction, so the vertical line of the connecting line can be more accurate.
The earth rotates 360 degrees in 24 hours, and turns 15 degrees in an hour, but the hour hand of a watch always turns twice as fast as the sun. According to this principle, the position can be roughly determined by the watch and the sun. At 6 o'clock in the morning, the sun is in the east and the shadow points to the west. At this time, the hour hand on the watch points to the sun, and the word "12" on the dial points to the west. If the dial turns 90 degrees, it is 6. At noon 12, the sun is in the south. If 12 is folded in half so that the character "6" on the dial faces the sun, the character "12" still refers to the north (Figure 6).
According to this method, we should consider the local time difference. We should adopt conversion of time and Beij as local time. Based on the east longitude 120 degree line. Every 15 degrees east longitude, Beijing time plus 1 hour, west longitude plus 15 degrees, Beijing time minus 1 hour, that is, local time. If the geographical coordinate of Urumqi is 87 degrees 40 minutes east longitude, then (65438).