Also recall that the top of a map is always north, so when taking map bearings always turn the compass housing to point the orienting arrow at the top of the map. Figure 4, has a map with magnetic north lines, rather than true meridian lines, and so declination is not a factor. Likewise if you are only calculating and working with bearings on a map declination is unimportant. Nautics. cardinal?) Simply look at your compass and the straight line across the dial (the number on the opposite side) is the return bearing. Look here - one of many sites which use the terms correctly. If you compass is so marked, you don’t need to adjust a map bearing before using it in the field, instead you just need to remember to align the magnetic needle with the declination marking rather than the orienteering arrow, and then follow the direction of travel arrow as usual. 4)Anything somebody else says is an azimuth is a bearing in our author's sense. I take issue with two terms, however. Figure 5 shows the 2005 declinations in the USA. The points of the compass are the vectors by which planet-based directions are conventionally defined. Nice addition to SP. But, at some point I will and I'd like to practice where I can't get lost. However, when you calculate map bearings from a map drawn to true north and then use the bearings in the field, you may be thrown completely off course if you don’t adjusting them for the declination of the area. Mark the vertex of your angle anywhere on the paper. We create a circle where the vertex of the desired right angle is a point on a circle. One degree equals sixty minutes, and one minute equals sixty seconds. It was mentioned early that one of the most important uses of a compass is for taking and following bearings. Read, The Effort Scale of Highpointing the Fifty US States. First take a bearing on landmark A, and adjust it to a map bearing and set that on the compass dial. As you spot a landmark, such as a mountain peak, take a field bearing on it, and convert it to a map bearing. The concept of the position angle is inherited from nautical navigation on the oceans, where the optimum compass course is the course from a known position s to a target position t with minimum effort. For example knowing the sun is in the east at 6:00 am, southeast at 9:00 am, south at noon, southwest at 3pm, and west at 6pm, you can take a bearing on the sun, and get a good idea of the current time. Ensure the shadow is cast on a level, brush-free spot. I bought a compass but haven't really used it yet, though I haven't needed it yet either. The "CW" column gives the fractional-point bearings increasing in the clockwise direction and "CCW" counterclockwise. To make a 90 degree turn without changing the bearing setting on your compass, simply turn your body until the red end (north end) of the magnetic needle points at the West marking (to turn right) or East (to turn left), as opposed to the normal North marking. Estimate the time you have been traveling, and the remaining about of daylight - this will help you figure out how far you have traveled. Once the steps are up, turn your body to align the magnetic needle back over the orienteering arrow (thus turning 90 degrees for a fourth and final time), and you will be back on course. Find which direction on a compass the micro:bit is facing. For example, (2007-1960) * 7 = 329; since there are 60 minutes in a degree 329/60 = 5.48 degrees or about 5.5 degrees. To do so, hold your hand up so it appears that your pointer finger is just touch the bottom of the sun. Over time compass markers have added features which make compasses work more harmoniously with maps and also more beneficially as stand alone tools. Say you are on a hiking trail, and to the west you can identify a mountain peak. Let’s return to the example above where we took a 315 degree (or NW) bearing on a rock outcropping, and lets suppose that enroute to the outcropping we encounter an obstacle which we must go around thus forcing us to deviate from our straight line course. Does it flow east, or northwest? The Boeing 727 is an American narrow-body airliner produced by Boeing Commercial Airplanes.After the heavy 707 quad-jet was introduced in 1958, Boeing addressed the demand for shorter flight lengths from smaller airports. Compasses with so-called global needles are available, and they can be used accurately in any part of the world. Aiming Off: When navigating to a target, if you realize that it could be easily missed if you get slightly off course one way, whereas missing the target the opposite way wouldn’t be a problem, you should use a trick known as aiming off. Not to worry if it's not there, but eliminating cumulative systemic error if it's there. Traditional compass roses will typically have the initials T, G, L, S, O, L, P, and M on the main points. If you are simply taking and following bearings in the field, you can completely ignore declination. We have all heard the saying that moss grows on the north side of trees. If you do lose your way, keep a cool head - a cool head can accomplish much, a rattle one nothing. Locks down a standard camera or GoPro™ without needing a special adaptor. --Lou Whittaker. Let’s say you are hiking in Utah where the declination is 13 degrees east. I find it faster than measuring distances with a ruler on the map, and a very precise way to calculate map bearings. Construction on paper. Yeah, and as to retracing your steps ... most of the time I can 100% trust my dog. Navigation texts dating from the Yuan, Ming, and Qing dynasties in China use a 24-pointed compass with named directions. While standing at the spot set your compass to any bearing between 0 and 120 degrees, pick a landmark along the direction of travel and take 15 steps toward it. So, a thousand double steps is about one mile. And we got it wrong. (That means that a 45° angle and a 135° angle add together to make a 180° angle -- or a straight line.) Over the years, I have crossed paths with cougars, been charged by moose, and spooked by grizzly bears. Pale Yellow sky at sunset indicates wet weather. This passion began in my childhood. That is the easy way to backtrack, of course you could also calculate your back bearing by subtracting 180 from your forward bearing of 315, and set the 135 degree (SE) difference at the compasses index line and then use the same body rotating method mention earlier, only this time you’d have the direction of travel arrow pointing your way. In aviation , north is usually expressed as 360°. Without moving the base plate turn the compass housing until the orienteering arrow points to the top of the map (remember that north is at the top of the map). Once you arrive at the rock outcropping, what bearing do you use to return to where you came from? Here's a minimal example to make the data and the Cartesian angles, and I've posted my brute force conversion to compass angle below. A scale of 1:250,000 means that 1 unit (be it inches, feet, meters, or whatever) on the map is the equivalent of 250,000 units in the real world. Follow the above described process to orient the compass on the map by passing the base plate edge over the landmark and rotating the base plate (not the dial) until the meridian lines of the compass parallel the north/south lines on the map, and draw a line on the map along the base plate edge. If you are lucky enough to be able to pick out a landmark that’s along the bearing, and also on the other side of the obstacle, you have nothing to worry about, just go around the obstacle and get back on course by reaching the landmark and aligning the red end of the magnetic needle over the orienteering arrow, and continue walking. He can do this by pointing the direction of travel arrow of his compass at himself and then turning his body so as to align the red end of the magnetic needle over the orienteering arrow, and he should notice that you are along the bearing, if not he needs to move left or right. It is a fun and useful means of navigation :). The third gives the equivalent bearing to the nearest degree from north or south towards east or west. input.compassHeading(); Returns. Home Browse. Typically one double step (that is just counting the steps of one of your feet, while ignoring the other) is about five feet. To overcome magnetic dip manufacturers must design compasses that have the needle balanced for the geographic area in which they will be used. The micro:bit measures the compass heading from 0 to 359 degrees with its magnetometer chip. I teach a land navigation class and I think or article was well done, Thanks for the post. To get an exact east-to-west line join the marks from two shadows of equal length. In summary, a compass is an invaluable tool that every outdoors enthusiast should understand how to use. Field to Map: add the declination (and the way to remember is you are going forwards in the alphabet from F to M) One method is to have a member of your party navigate the obstacle, and then treat him like a landmark. This is an alternate convention that is useful where you're doing engineering, surveying or air and sea navigation because it makes trig easier. Resection And with O as center , draw an arc which cuts line segment OB at X . Compass Heading. Note that this trick doesn't really work when one is near either of the poles, as the sun hovers over the horizon longer at those locations. Daytime temperatures drop about five degrees Fahrenheit per 1,000 feet of elevation gain. Let’s say your bearing on the outcropping measured 315 degrees (or NW). There are no irregularities to trip over; the closest principal wind always comes first, the more distant one second, for example: north-by-east is "Quarto di Tramontana verso Greco"; and northeast-by-north is "Quarto di Greco verso Tramontana". Think to yourself "my compass is pointing off by 20 degrees to the east, my right, so to go true north I really need to point my direction of travel arrow 20 degrees to my left". When you take a field bearing and want to plot it on a map, take it with the magnetic needle pointing to the declination figure rather than the orienting arrow, and then you can use the bearing on the map without adjustment. If you know by how many minutes on average the declination of your area is changing per year you can use that to update an out of date map figure. The Big Dipper rotates around Polaris. A compass trick used to avoid declination adjustments is to place a piece of scotch tape over the compass dial starting at the east declination and ending at the value of declination plus 180. Hence forth, this article focuses solely on the orienteering compass. Some compasses have a declination scale marked within the housing. In either the approximate or the exact case stand with the first mark on your left, and the second on your right, and you will be facing toward true north. When a single direction is specified, it may be prefaced by the character 單 (meaning single) or 丹. Headings mid-way in-between are compounds as in English. Stop, add 120 degrees to your initial bearing, pick out a landmark along that bearing and walk another 15 steps toward it, stop and once again increase your bearing by 120, pick out a third landmark and again walk 15 steps. Once you’re past the front of the obstacle turn 90 degrees again, by rotating your body until the red end of the magnetic needle is over the orienting arrow, and walk past the obstacle. Consider this, say you are in Rhode Island where the declination is 15 degrees west, and lets say your map bearing is 0 degrees (or directly north). The website also tells you by how much declination is changing per year. Note that lost people tend to wander in circles; as such above all don’t run around aimlessly. Next you pick out two permanent landmarks which are preferably about 90 degrees apart, and take a bearing on each. In field orienteering it’s all about getting the direction of travel arrow pointing in the correct direction. Now, read the bearing at the compasses index line, and follow the bearing in the field! Agriculture; ... View Lessons (135) National … Latitude and longitude are measured in degrees, minutes and seconds. To use the bearing in the field you would subtract 13 (the declination) from 135 resulting in 122 and simply set your compass dial at 122 degrees and then follow that bearing to your destination. Your welcome! And let me move the protractor out of the way so we can get a good look at it. First, decide whether the arrow is closer to N or to S. You can see it's closer to the S. Next, decide whether it's closer to the E or the W. It's closer to the E. Finally, measure the angle between the arrow and the S. That angle is 77°. So if declination on the 1960 map is 15 degrees east, the 2007 value is 15-5.5 or 9.5 degrees east. In fact, when you use 2 compass directions, it is called determining position by intersection, but it comes under resection As a, This page was last edited on 3 January 2021, at 11:30. [4] Navigators used ordinal directions , instead of compass degrees, e.g. Whereas, at the south magnetic pole (located just off the coast of Wilkes Land, Antarctica in 2007) the north-seeking end of the needle is deflected upward. Clearly, the smaller the scale, the more detail is revealed. En route, when the rock outcropping leaves you line of sight pick out an intermediate landmark along the bearing, so you don’t have to constantly look down at your compass. [7], By the middle of the 18th century, the 32-point system had been further extended by using half- and quarter-points to give a total of 128 directions. If you are not on a position line, you will need to identify two landmarks in both the field and on the map to pinpoint your location. So rotate you body counterclockwise until the magnetic needle lines up with the 20 degree marking on the compass housing dial. If you have a topographic map and you can identify both landmarks on the map, you can use you compass with the map to get a bearing thus enabling you to travel accurately to landmark B. Join OREx 11.1, 4Construct the following angles and verify by measuring them by a Protractor : 135° 135° = 90° + 45° So, to make 135° , we make 90° and then 45°Steps of constructionDraw a line OAA’. Also, modern compass are available which can be set to automatically adjust for declination if you don’t want to bother with the math, if so equipped consult your compass booklet to learn how to set it. Say you want to travel to a large rock outcropping on the horizon, which is currently visible to you, but which may leave your field of vision when you walk into a dip, or when pending clouds come in or the sun sets. One he has cleared the obstacle talk him into position along your original bearing. Remember, the magnetic needle of a compass is for use in the field, and is never used on a map. Shasta California, and white-water rafted on the Gauley River of West Virginia. Notice you have arrived back at your original starting location. Working with one meter number, can be less confusing than working with three degrees, minutes, and seconds values. Typically the eight principal points are sufficient to know. Map to Field: subtract (and the way to remember is you are going backwards in the alphabet from M to F) Unfortunately, it would require a separate article to fairly explain maps, but it’s still worth looking at some map basics here. That distinction seems to no longer apply. This looks really great. Another use for triangulation is in being able to return to an exact location. We say areas to the left of the line have east declination and those to the right have west declination. Create. Very few activities provide me with as much joy as hiking, camping, skiing, mountain biking, rock climbing, ice climbing and exploring. (30), The Effort Scale of Highpointing the Fifty US States. "It is the custom in the United States Navy to box from north and south toward east and west, with the exception that divisions adjacent to a cardinal or inter-cardinal point are always referred to that point. Now plot this line back to the position line (in this case the hiking trail) you are known to be on, and where the line crosses the position line is your exact location. Let’s begin our introduction to compasses by taking a look at a standard, modern day, orienteering compass, and identifying its parts. I'm not sure, but prehaps the military uses the word azimuth instead of bearing. The final three columns show three common naming conventions: No "by" avoids the use of "by" with fractional points. Hence a roll out heading read from the compass of 127 degrees would be used to actually fly the heading of 135 degrees. At night find the North Star and mark that direction on the ground to guide you come daylight. Map bearings can then be set on the compass dial as read from the map, but the magnetic needle now needs to be aligned with the tape line, rather than the orienteering arrow. Actually you don’t need any other bearing besides the 315 degrees already set on your compass. To find it, locate the Big Dipper and follow the two pointer stars at the end of the cup to the tail of the Little Dipper, Polaris is the last star on its tail, see Figure 7. Then we'll start getting into obtuse angles, 100, 110, 120, 130, 140, 150. Animation of how to construct a 60 Degree Angle using just a compass and a straightedge (ruler). For a dodecagon, n=12. The North Star can be used to measure declination. The Sun is at 15 degrees true * military time (or one hour less if daylight savings time is in effect). Tramutana, Gregale, Grecho, Sirocco, Xaloc, Lebeg, Libezo, Leveche, Mezzodi, Migjorn, Magistro, Mestre, etc. Each point has an angular range of ​11 1⁄4 degrees where the azimuth midpoint is the horizontal angular direction (clockwise from north) of the given compass bearing; minimum is the lower (counterclockwise) angular limit of the compass point; and maximum is the upper (clockwise) angular limit of the compass point. Why not verify if that is true in your area? Assume you know you are at landmark A in the field, and you want to travel to landmark B, but you can’t see it. Often you are required to construct some angles without using a protractor. You might be the only object to throw a shadow when walking in barren terrain like a desert. Taking O as center and any radius, draw an arc cutting OA at B.3. The UTM grid is more precise than latitude/longitude because USGS maps identify UTM scales every thousand meters compared to only every 2.5 minutes (about 3500 to 5000 meters) for latitude and longitude. A vessel heading ESE is on a course of _____ 112.5 degrees. Only at the equator is the needle unaffected by vertical magnetic forces. The names of the compass point directions follow these rules: In summary, the 32-wind compass rose is yielded from the eight principal winds, eight half-winds and sixteen quarter-winds combined together, with each compass direction point at an ​11 1⁄4° angle from the next. Before beginning to use a compass one should familiarize himself with basic directions and their degree readings. In the Northern Sky the Big Dipper is one of the most familiar asterisms of the constellation Ursa Major (the Great Bear). Knowing where true north lies, now follow the declination adjustment rule by subtracting 20 east declination degrees from your 360 degree bearing and set your compass dial to 340 degrees. Note such things as landmarks, bearings between landmarks, distances and elevations. As the Earth moves around the sun the angle of our view of the Big Dipper changes and thus is different for each season. In Chinese, Gaelic and less commonly in Japanese, the part meaning east or west precedes the other. Set your compass dial at 360, and point the direction of travel arrow north at the longer stick. This technique is referred to as a double-needle (雙針) compass. For example if you are told that a landmark is SE of your location, you know that is 135 degrees, or conversely if you know you need to go West but you calculate the bears as 90 degrees you will instinctively realize the bearing is wrong, as West is at 270 degrees (turn your compass around, you have committed the classic 180 degree error). Each of the 96 fractional points can be named in two ways, depending on which of the two adjoining whole points is used, for example, N3/4E is equivalent to NbE1/4N. Now use compass and open it to any convenient radius. The traditional mariner's wind names were expressed in Italian, or more precisely, the Italianate Mediterranean lingua franca common among sailors in the 13th and 14th centuries, which was principally composed of Genoese (Ligurian), mixed with Venetian, Sicilian, Provençal, Catalan, Greek and Arabic terms from around the Mediterranean basin. Reverse Bearing: When hiking in and back out from somewhere one should know who to calculate a reverse (or opposite) bearing. The traditional compass rose of eight winds (and its 16-wind and 32-wind derivatives) was invented by seafarers in the Mediterranean Sea during the Middle Ages (with no obvious connection to the twelve classical compass winds of the ancient Greeks and Romans). Repeat the process with the second landmark and the intersection of the two lines is your exact location. A bearing is the direction from one spot to another, measured in degrees, from the reference line of north; in other words it’s one of the 360 degrees of the compass rose. Global needle compasses can handle tilts up to 20 degrees. To return, just point the direction of travel arrow at you, instead of forward, and then rotate your body until the orienting arrow lines up with the red end (north end) of the magnetic needle, and then walk straight ahead while keeping the magnetic needle over the orienteering arrow (just as you did in going to the rock outcropping). If possible consult your compass, if not possible pay attention to sunset or sunrise which will indicate east and west, or use a wristwatch as a compass. That angle is 103° (shown in parentheses). Being aware, will reduce lost time, and disorientation, and make your outdoor experiences more rewarding. The table below shows how the 32 compass points are named. Great article! Nicely done. Now the direction of travel arrow is pointing to true north. Next, with the adjusted bearing set on the compass dial, find the landmark on the map, and point the direction of travel arrow in the direction of the landmark with the edge of the base plate on the landmark. On this page we show how to construct (draw) a 90 degree angle with compass and straightedge or ruler. Roughly the distance to the North Star from the Big Dipper is 5.5 times the distance between the two pointer stars forming the non-handle side of the cup. The latitude and longitude grid allows us to calculate an exact point using these lines as X axis and Y axis coordinates. The supplement of either of the 45° angles is a 135° angle. A trick to do so is to count your double steps. If you flesh it out a bit more I will gladly use it in the article. However, I want the angles in compass (polar? I have included it in the article. Also have him take a back bearing on you to confirm he is in indeed back on course. The "traditional" names of the eight principal winds are: Local spelling variations are far more numerous than listed, e.g. The bottom of the rotating housing is marked with an orienting arrow, and meridian lines. Make a note of each landmark and it’s bearing, then when you return to the general area all you need to do is position yourself where the two bearings match and you will find you hidden water bottle. You did a terrific job on this page! Wait 10-15 minutes, as the shadow moves from west to east (the opposite side the sun moves on, ie the sun moves from the east to the west -- but both the shadow and the sun move in a clockwise direction). A 135° angle is the supplement of a 45° angle. Some disciplines such as meteorology and navigation further divide the compass with additional vectors. Keeping the edge of the base plate on the landmark, rotate the base plate (not the dial) until the meridian lines of the compass align with the north/south lines of the map. 135 The Scotty Portable Camera Mount is fully twistable turnable rotatable and best of all instantly portable. The mechanical declination adjustment on so-enabled compasses uses this very procedure. Thus, a compass built for use in North America, will not work in South America. To measure your latitude, point a stick at the North Star, then measure the angle the stick makes from a level horizon. For example, if you walked south following a 177 degree bearing, and turned around to return to your starting point what bearing would lead you back?