About Compass
In outdoor activities, such as geological surveys, mountain climbing, hiking, exploration, tourism, etc., in order to prevent getting lost and correctly determine the location and direction, you must master positioning and lateral methods. In nature, some animals, such as pigeons, have the instinct to identify directions. Some members of the human race also have this ability, but the vast majority of people do not have it, or they only have this potential. Therefore, determining direction in the wild mainly relies on experience and tools. There are many ways to determine direction and position in the wild. Here are some common methods.
Use a compass (compass) to open the compass or place the compass horizontally to center the bubble. At this time, after the magnetic needle is stationary, its black end marked with "N" points to the north.
In addition to measuring the direction of true north, a compass or compass can also measure the specific direction of a target. The method is to open the compass and align the sight with the target, or turn 0 on the dial. Align the scale with the target so that the target, 0 scale and the magnetic midpoint are on the same straight line. After the compass is level and stationary, the scale pointed by the N end is the direction from the measuring point to the target. For example, the N end of the magnetic needle points to 36°. Then the target is 36° north by east of the measurement position.
Although it is easy and quick to use a compass or compass to identify the direction, you need to pay attention to:
1. Try to keep it as level as possible; 2. Do not get too close to magnetic materials; 3. Do not place the magnetic needle The S end is mistakenly set to the north, causing a 180° direction error; 4. Master the magnetic declination in the active area and make corrections.
Use the sun
On a clear day, you can easily know the east and west based on the sunrise and sunset, and you can also judge the direction, but it can only be a rough estimate. There are several more accurate determination methods:
1. The direction of the watch "halve the hour to the sun, and 12 points to the north". Generally, it can be quickly done between 9 a.m. and 4 p.m. To identify the direction, use the direction pointed by half of the time to face the sun. The 12 o'clock scale is north. For example, at 14:40 in the afternoon, half of the time is 7:20. Point the hour hand towards the sun, then 12 points is north. , or place the watch flat, with the hour hand pointing to the sun, and the opposite extension direction of the hour hand and the bisector of the 12 o'clock scale is north; or place the watch, stand a small stick vertically in the center of the watch and rotate the watch so that the shadow of the stick is in line with the When the hour hands coincide, the bisector between the hour and 12 o'clock scales is north.
It must be noted: (1) When determining the direction, the watch should be placed flat; (2) It should not be used around noon in the area between 20°30′ south and north latitude, that is, the longitude of standard time shall prevail. Every 15° eastward adds 1 hour, and every 15° westward decreases 1 hour.
2. The direction of the solar shadow is measured on a sunny day. A wooden stick is erected on the ground. The shadow of the wooden stick moves with the change of the position of the sun. These shadows are shortest at noon, and the line connecting their ends is a straight line. The vertical line of this line is the north-south direction.
Draw a series of concentric circles on a piece of 50×50cm drawing paper. The radius of the concentric circles increases in 1cm increments. Nail it on the flat plate and fix it horizontally. Place a 12-15cm long thin steel The needle or needle-like object is inserted vertically in the center of the circle. When the position of the sun changes, the endpoints of the shadow will always intersect with concentric circles. Plot these points, and then connect the two points on the same circle with straight lines. Connect the midpoints of these straight lines to the center of the circle. This connection is north and south. Direction line, the direction of the arc top is north.
Night Stars
When it is night, the direction can be determined based on the Polaris and the Southern Cross.
1. Polaris
Polaris is located in the sky in the true north, and its appearance angle is equivalent to the local latitude. Based on this, Polaris can be found quickly. Usually determined based on the Big Dipper (Ursa Major) or the W star (Cassiopeia).
The Big Dipper is a group of seven bright stars, shaped like a spoon. The point where the two β on the head of the spoon are connected to α and extended about 5 times is the Polaris.
When the Big Dipper cannot be seen, you can look for the North Star based on the W star, the Cassiopeia constellation.
The Cassiopeia constellation is composed of five brighter stars, shaped like the letter "W". The opening direction of the letter is about twice the width of the opening and is the North Star.
2. Southern Cross
In areas south of 23°30′ north latitude, the Southern Cross is sometimes visible at night. It consists of four brighter stars, shaped like a "ten" In the lower right corner of the word, four and a half times the length of the line connecting the two stars from γ to α (without stars) is the direction of due south.
Land features and plant features
Sometimes some features and plant growth features in the wild are good direction signs. Increasing knowledge in this area can help you quickly identify the direction.
1. Features of land features
Houses: generally open to the south, especially in northern my country:
Temple: usually open to the south, especially in temples The main building;
Prominent features: The base on the north side is moist and may grow low bryophytes.
2. Plant growth characteristics
Generally, on shady slopes, that is, the northern slopes, low ferns and vines are more developed than on the sunny side.
The branches and leaves of individual plants are more lush on the sunny side, while moss may grow on the shaded trunks facing north.
Clear annual rings can be seen in the cross-sections of the trunks of many trees in northern my country. The annual rings on the south side are sparse, while the annual rings on the north side are denser.
Use the surrounding environment to detect directions
If you are alone in the forest and have a map but forget to bring a compass, can anyone tell you the direction?
When I was in primary school, my teacher taught me the common sense that the sun rises in the east and sets in the west. From the position of the sun, we can roughly know the direction. But how should we judge if the sun is covered by clouds or it rains?
If you get lost on a cloudy day, you can get your bearings by looking at the growth of moss on trees or stones. In terms of trees in the Northern Hemisphere, the south is where the leaves grow thickest. If you cut a tree, the side with wider growth rings and the side with moss is the north.
／Sun
The sun rises in the east and sets in the west. This is the most basic way to identify the direction. You can also use the stick shadow method to measure it. When the sun is enough to form a shadow, At that time, erect a straight stick (more than 1 meter) on the flat ground and place a stone (or make other mark) on the top of the stick's shadow. The shadow of the stick will move with the movement of the sun. After 30 to 60 minutes, place another stone on top of the shadow of the stick again. Then draw a straight line between the two stones, and in the middle of this line draw a straight line that intersects it perpendicularly. Then step on the first marked point with your left foot and the second marked point with your right foot. At this time, the front of the standing person is due north, the back is due south, the right hand is east, and the left hand is west.
／Use the stars
In the northern hemisphere, Polaris is usually the target. The key to using the North Star to identify directions at night is to accurately find the North Star in the vast sea of stars. There are many ways to know the North Star. Here is a simple and effective one:
First look for the dipper-shaped Big Dipper (a), and extend the distance between the two stars on the handle of the dipper five times. Polaris (d) can be found on this straight line. The stars on these two handles are generally called key planets. If you can't see the Big Dipper, look for the Cassiopeia constellation (b) in the opposite direction. The Cassiopeia constellation is formed by five stars. They look like the shape of the English letter M or W tilted to one side. Draw a straight line from one of the stars in the constellation Cassiopeia to find the North Star at almost the same distance from the Big Dipper to the North Star. The direction of Polaris is true north.
／Looking at the direction with a watch
I want to know the direction but I don’t have a compass in my hand. In this case, you can use your watch to find your direction as long as the sun is shining.
Put the matchstick upright on the ground, and then place the watch horizontally on the ground. Overlap the shadow of the matchstick with the short hand. The direction of the twelve o'clock on the surface and the middle of the scale pointed by the short hand are south. , the opposite side is north.
If you don’t have any matches, you can use small branches instead, and try to use shadows to be more accurate.
If you are engaged in challenging survival activities, remember to wear a watch. At this time, an ordinary watch is more valuable than a digital watch. Because the hour and minute hands on an ordinary watch will become an important tool for survival when necessary.
／How to use a compass
Using a compass can make the map consistent with the actual terrain, and find out where you are now and the direction of the destination you are looking for.
The compass must be held horizontally and away from the following items to avoid magnetic needle confusion: the compass should be 10 meters away from barbed wire fences, 55 meters away from high-voltage wires, 20 meters away from cars and airplanes, and objects containing Magnets such as magnetic containers etc. 10 meters.
／Steps to use a compass to find out your current location:
① Make the actual terrain consistent with the direction of the map.
② Find two visible targets on the map.
③ Point the forward line (or long side) of the compass toward one of the target objects 2
④ Find the circle that matches the arrow and the pointer (north).
⑤ Place the circle in the north position of the map without changing its direction.
⑤The tip of the long side of the compass matches the target on the map.
① Draw a straight line between the arrow in the circle and the extension of the magnetic north line.
③ Follow the same method for another target. The intersection of the two lines is where you are now.
／Use a compass to find out the direction of travel
① Make the straight line connecting the current position and the destination match the progress line (long side) of the compass.
②The arrow in the circle is parallel to the magnetic north line (the arrow is in the upper part of the map).
③ Take the compass away from the map and hold it in front of your body.
④Twist your body until the arrow and pointer overlap.
⑤ Overlap the direction of the line, which is equal to the target direction of the map.