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(1) Place the protractor index where the azimuth line cuts a north-south grid line, aligning the base line of the protractor directly over the intersection of the azimuth line with the north-south grid line. Consider that if the object was magnetically due north of you (0 degrees magnetic), then physically it would have to be 12 degrees east of Grid North [Noun. Intersection, using a straightedge. Magnetic declination correction converts azimuth values between the Magnetic North and True North systems. Converting Magnetic Azimuth to grid Azimuth | Rokslide Forum Once accurate magnetic declination and grid convergence angles are acquired, all that is needed to change reference systems is to add or subtract these angles from one another. is, must be between zero and 360 degrees. State Plane Coordinates: Geodetic Azimuths and Grid Azimuths The angle can be clockwise or counter clockwise from True North to Grid North. I don't get why you need to substract your compass value GN 4 3 1. (6) The intersection of the lines on the map is your location. WebConverting azimuths to quadrant bearings or vice versa is easy. There are 180 140 = 40 degrees between the South and the point, therefore the quadrant bearing is S40E. To convert a magnetic azimuth to grid azimuth, subtract G-M angle. If you have a magnetic azimuth of 270 degrees, and the G-M angle is 8 degrees, your d. Conversion. True north is usually represented by a star (Figure 6-1). Determine the grid coordinates to the desired accuracy. hbbd``b` @ b*? Subtract the GM angle to convert a grid azimuth into a magnetic azimuth. The graphic below demonstrates for both East & West Declination. How to convert magnetic azimuth to grid azimuth. endobj A glance at the completed diagram shows whether the given azimuth or the desired azimuth is greater, and thus whether the known difference between the two must be added or subtracted. The magnitude of the correction angle depends upon its location within the grid and its latitude. The north that is established by using the vertical grid lines on the map. WebConvert the Magnetic Azimuth of 65 to a Grid Azimuth. This is easy to remember. Thus to convert from a magnetic bearing to a Grid North reference you would subtract 8 23. The azimuth is the most common military method to express direction. Figure 6-19. This is the convention for any plane coordinate system, so that north is always up, and always the same direction. Figure 6-16. But which equation yields the correct back azimuth? What is sunshine DVD access code jenna jameson? In either case, the listed Declination, or GM Angle on the map (which may or may not be correct due to Magnetic North Pole movement) is for the center of the map, and depending on the whats under or on top of the surface, the Declination degree may be distorted during your trip. (c) Examine the declination diagram on the map and determine the direction of the magnetic north (right-left or east-west) relative to that of the grid-north prong. (5) Repeat 3 and 4 using a second known position. (3) Determine the magnetic azimuth to the unknown position using the compass. A protractor is used to measure the angle between grid north and the drawn line, and this measured azimuth is the grid azimuth (Figure 6-4). Magnetic North - based on the earth's magnetic field, and is used to describe compass direction. The magnetic north is usually symbolized by a line ending with half of an arrowhead (Figure 6-1). Azimuth and A = Azimuth, When using it. 3 0 obj<>>>/MediaBox[0 0 612 792]>> For your convenience, you can use a UTM Universal Transverse Mercator AKA USGS 7.5 minute map. WebAdd the GM angle to convert a magnetic azimuth into a grid azimuth. Intersection is the location of an unknown point by successively occupying at least two (preferably three) known positions on the ground and then map sighting on the unknown location. Military personnel need a way of expressing direction that is accurate, is adaptable to any part of the world, and has a common unit of measure. 100 - 80 = 20 Susan is 20 degrees off course. Pakistan ka ow konsa shehar ha jisy likhte howy pen ki nuk ni uthati? Such procedure is important when working with a map for the first time. CONVERTING GRID AND MAGNETIC AZIMUTHS HOW AND Theyre ok to use; theyre typically in 1:24,000 scale, and you need to ensure your map tools correspond in scale. Determine the grid coordinates to the desired accuracy. 8 0 obj endobj No mathematical equation is necessary because the compass itself has the declination already accounted for by your adjustment. This needs to be taken into account when navigating with a map and compass. endstream endobj 1784 0 obj <>stream WebIn this example, the known azimuth is 270 magnetic. Using a protractor, draw a line for the back azimuth on the map from the known position back toward your unknown position. Ok, but your longitude lines on your map dont follow magnetic north/south, depending on your location. (2) Put your finger on the grid north line, now move it to the magnetic north line. To convert degrees to mils, multiply degrees by 17.78. c. Grad. While this seems a simple task, misunderstandings surrounding the relationship between these references can cause a target to be missed. The first step to converting magnetic azimuth to grid azimuth is to determine the declination angle. To convert this UTM Grid North direction to a True North direction, you must apply the grid convergence to the calculated UTM Grid North direction. Author and/or Instructor: Jan Van Sickle, Senior Lecturer, John A. Dutton e-Education Institute, College of Earth and Mineral Sciences, The Pennsylvania State University; V3 Consultants, Lakewood, CO. For example, when you convert the geographic coordinates latitude N 30 00' 00" and longitude W 95 00' 00" to UTM coordinates (using the Hayford Inter-national - 1924 Ellipsoid), the computer will display the following results: UTM Coordinates: Hemisphere = North Zone = 15. *r\6}ZM{ru s/])7ZiV?.kBh%2`43`1(C`BE&q]I~u_ NB^'zNyv degrees nor less than 0 degrees as that range is the range of a Several field-expedient methods to determine direction are discussed in Chapter 9, paragraph 5. To determine the back azimuth all that is necessary is the (2) Without Notes. endstream endobj 1782 0 obj <>stream This protractor represents the azimuth circle. An azimuth is defined as a horizontal angle measured clockwise from a north base line. There is an angular difference between the grid north and the magnetic north. This gives you a grid azimuth of 77 degrees. A circle equals 6400 mils divided by 360 degrees, or 17.78 mils per degree. Now, if you want to convert a MAZ to GAZ using the example above (in that you have a MAZ of 180, simply add the 15 degrees declination to the 180, and you have a correct GAZ. There is true north (the northern axis around which the earth rotates), magnetic north (the direction compasses point, which changes slightly every year) and grid north (the somewhat arbitrary point where all of your grid lines would converge if your map could extend all the way to the North Pole. If you know who Lars Ulrich is, you can convert your azimuths. In the last post onMagnetic Declination, the impact it has on azimuth/bearing accuracy was described. A relationship can be established between degrees and mils. All the norths are parallel in the plane systems; this is, of course, unrealistic. The conversion (whether to add or subtract) depends on whether your map has an. Their values and rates of change can be obtained from Computer programs like GEOMAG or "world magnetic variation charts" or "isogonic charts" which are issued by all major hydrographic institutes in the world once every five years (1980, 1985, '90, etc.). ' vuxcwxXONIq$eC CRFRERH>QF4J#[~CO]U26#iB(V]vLa`'xLa1?Ro~& Figure 6-13. 4. I'll be doing it. The degree scale is graduated from 0 to 360 degrees; each tick mark on the degree scale represents one degree. endobj 1790 0 obj <>/Filter/FlateDecode/ID[<2B0C2CAC99B5C942A1B86AECE94C0B5C>]/Index[1778 23]/Info 1777 0 R/Length 68/Prev 337901/Root 1779 0 R/Size 1801/Type/XRef/W[1 2 1]>>stream In the jpg below, you can see the declination window at 6 oclock on the compass, or specifically, at Zero degrees. The declination diagram (Figure 6-8) shows the angular relationship, represented by prongs, among grid, magnetic, and true norths. GM Angle= 7W 2. (3) The G-M angle diagram should be constructed and used each time the conversion of azimuth is required. the back azimuth, and 3) the correct back azimuth must be in the So, its good to check the on line or other sources for up to the date declination numbers. Since the location of magnetic north does not correspond exactly with the grid-north lines on the maps, a conversion from magnetic to grid or vice versa is needed. In Colorado, the central meridian is 105 degrees, 30 minutes West Longitude, as shown here, on the left you have station D266 and on the right, station Fink. It can be expressed as right, left, straight ahead, and so forth; but then the question arises, To the right of what? This chapter defines the word azimuth and the three different norths. hb```"?f" !E5r|x:s9DvD*\^b"/mKG@@al>;/UbD-m- 1?(RA)@'7$Z4 ER#cJCg((`R``A*x stream FM 3-25.26 Map Reading and Land Navigation - 550 Cord With these three references it is a simple matter to determine whether declination and/or convergence need to be added or subtracted to switch from one system to the other. (6) Repeat 3, 4, and 5 for a second position and a third position, if desired. 4 0 obj <>stream hTak0+VtHpfePAKcH`#IqIz;KYAA"&8$@,(.Q5{u>-q 1"ora-H>:PB6GDE]>>^M&i6)}}}qfWY@vk This circle is divided into 360 degrees or 6400 mils (Appendix G). An azimuth is defined as a horizontal angle measured clockwise from a north base line. Another unit of measure, the mil (abbreviated ), is used mainly in artillery, tank, and mortar gunnery. e. Applications. None of your azimuths need conversion until such time as you use a different compass one that cant be adjusted similarly. The straight edge method is used when a compass is not available. For mils, if the azimuth is less than 3200mils, add 3200 mils, if the azimuth is more than 3200 mils, subtract 3200 mils. This equationmustbe memorized if you dont have a declination adjustable compass in order to stay accurate and end up on or near the coordinate youre aiming for on the last leg of your navigation. The magnetic azimuth is determined by using magnetic instruments, such as lensatic and M2 compasses. This method can be used at night. When was AR 15 oralite-eng co code 1135-1673 manufactured? WebThe GM angle is used to convert magnetic azimuth to grid azimuth and vice versa: Grid azimuth - determined with a protractor and is measured from grid north. Intersection, using map and compass. endobj b. Mil. The University of Akron : YOU BELONG HERE! : The University WebThe Azimuth Calculator is an incredibly simple tool you can use to determine the azimuth between two specific points on earth. As the request is for the back azimuth, then what is wanted is Figure 6-9. To convert a magnetic azimuth to a grid azimuth, subtract the G-M Angle. If youre not using that type of compass, youll always have both Grid and Magnetic Azimuths to deal with when navigating. a. Flying a plane for instance. What is the cast of surname sable in maharashtra? Then, what exactly is a grid azimuth? Conversely, if its West, Magnetic North is West of your location. That's why I believe the adding and subtracting methods are the wrong solution that can be completely avoided. Azimuths are conventionally measured in a clockwise direction from north with 0 degrees corresponding with north, 90 degrees east and 180 degrees south. You are using an out of date browser. The rules for converting azimuth angle to true azimuth are summarised in the following table: Examples: If latitude is 55 o N, LHA is 145 o and azimuth angle is 120 o then true azimuth is 360 o Z i.e. If you plot your grid azimuth on a map and it reads (for example), 180 degrees (GAZ), and you know your local declination is 15 degrees East, and you wish to convert your GAZ to a MAZ, simply subtract the Declination of 15 degrees and youll have a 165 MAZ, or magnetic azimuth that you can use with your compass. On the Earth they are not parallel with each other. %%EOF (b) To use a magnetic azimuth in the field with a compass, first change the grid azimuth plotted on a map to a magnetic azimuth (Figure 6-11). Is Grid North the same as magnetic north? The other choice, Ab = A + 180 = 223 + 180 = 403 degrees, ^ni`H2pI35%S8lKXoboAJXT/k]3 @[J Plotting an azimuth on the map. Depending on what your doing it can matter a lot. TO CONVERT A GRID AZIMUTH TO A MAGNETIC Save my name, email, and website in this browser for the next time I comment. Convert a magnetic azimuth of 347 to a grid azimuth (using a 5Westerly G-M Angle) Answer: 347 - 5 = 342 Answer : 347 - 5 = 342 9. Grid north may be symbolized by the letters GN or the letter y (Figure 6-1). 2 0 obj Disclosure: Some of the links above are affiliate links. (3) Note that the protractor is cut at both the top and bottom by the same north-south grid line. (2) Thatll be covered in one of the next posts on this subject. b. Grid and Geodetic Azimuths | GEOG 862: GPS and GNSS for It explains in detail how to determine the grid and the magnetic azimuths with the use of the protractor and the compass. xr0A{K;M64%X GqJ8u_~E ,E}\x6%aX@Bl8p WebTo Convert Azimuth Angle to True Azimuth. Given this knowledge and the variable definitions Ab = Back H[k0e0Zu(fW9QKq:.LJ)~OBhmUEz]@F|;xv?H'F07@F{d;F#: F8hMg$/[?Y% FC4s~ujTzF8[4ZOEOi[nkJ . When using an azimuth, the point from which the azimuth originates is the center of an imaginary circle (Figure 6-2). 7 0 obj Notice that, in both cases, that grid north is exactly parallel with the central meridian. Figure 6-7. (c) Convert a grid azimuth to a magnetic azimuth when the G-M angle is greater than a grid azimuth (Figure 6-12). (d) Remove the protractor and draw a line connecting the known point and the mark on the map. Figure 6-17. 11K views 8 years ago How to convert from a grid azimuth to a magnetic azimuth. <> Therefore, there is a value, shown here in blue, called convergence. <> knowledge that 1) the back azimuth is the opposite direction of the There are several types of protractorsfull circle, half circle, square, and rectangular (Figure 6-5). { yBeDS#5HXM5B^*`Flm5^TQR!j.AzS!OZhkO\%[mk|lq#N. Doesn't matter if you're in the northern or southern hemisphere. A rule to remember when solving such problems is this: Nomatter where the azimuth line points, the angle to it is always measured clockwise from the reference direction (base line). Magnetic Declination models are updated every year. The grad is divided into 100centesimal minutes (centigrads) and the minute into 100 centesimal seconds (milligrads). c. Field-Expedient Methods. Using the laser range finder to determine the range enhances your accuracy in determining the unknown positions location. The surface location to target direction will therefore be referenced to Grid North. Convert user entered true azimuth to magnetic azimuth c. Determine the magnetic azimuth from your location to the distant known point. True Copyright 2023 ScienceAlert.quest | Powered by Astra WordPress Theme. range of zero to 360 degrees. WebPlease note that the sum of the grid azimuths (in red) at station Fink and station D266 is 360 degrees. The most common unit of measure is the degree () with its subdivisions of minutes () and seconds (). Please note that the sum of the grid azimuths (in red) at station Fink and station D266 is 360 degrees. ^z].;@ If you're using a regular map with a declination diagram this will always work. Magnetic readings are obtained with magnetic instruments, such as lensatic and M2 compasses. 2282 0 obj <> endobj The answer is that you can use a compass or an app like Google Maps on your phone to find out the grid azimuth. (2) The user should re-read the azimuth between the azimuth and north-south grid line to check the initial azimuth. When using the protractor, the base line is always oriented parallel to a north-south grid line. endstream endobj 2283 0 obj <>/Metadata 139 0 R/Pages 2280 0 R/StructTreeRoot 171 0 R/Type/Catalog>> endobj 2284 0 obj <>/MediaBox[0 0 612 792]/Parent 2280 0 R/Resources<>/Font<>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI]>>/Rotate 0/StructParents 0/Tabs/S/Type/Page>> endobj 2285 0 obj <>stream Converting to a magnetic azimuth on a map. Add the GM angle to convert a grid azimuth into a magnetic azimuth. (c) Keeping the index at this point, align the 0- to 180-degree line of the protractor on the vertical grid line. When working with the UTM system, the calculated direction between two UTM coordinates is referenced to Grid North. This is because 2 degrees and 362 degrees are located at the same point on the azimuth circle. It may not display this or other websites correctly. 0 Draw an arc from the grid prong to the magnetic prong and place the value of the G-M angle (Figure 6-9). Web(1) Look at the declination diagram and determine the direction between the line representing grid north and the line representing magnetic north. "'pGX. <> The chosen sign convention displays Grid North as "x" number of degrees east or west of True North. Swarovski ATC Compact Spotting Scope Review, Helping Mule Deer Thrive: Muley Fanatic Foundation, Growing Big Mule Deer with Wildlife Prof Randy Larsen. WebTo convert a magnetic azimuth to a grid azimuth, add the value of the G-M angle to the magnetic azimuth. Azimuths Surveying | What Is Bearings Surveying Ab = A - 180 = 223 - 180 = 43 degrees Grid North - based on a specific coordinate system and is used to define the relative direction of a line. xUMo1+1vmR6!j?__wrVxuzsei8Vmq.a+Qgl_9lz(A#l$ fQUzp6`Y+F,aeBBa[[c ^`;x1zKEyH9 NYtK,|m7-oF=HI)''UG~PycHNu-3r+|Q!vmR0T KiU)QHc|j'szMV+: s BH4/&`N3qgTR--H\Bg,R7d,B)th|1u"Uf0#bOzM&Z6fFmtQcX825Qb-Kyu ,F!bW\{JI6=aGc9MX'z_R0K}y%!> Find out how to get your bearings with this beginner-friendly tutorial and discover some of our favorite things nearby!. a. ?101rT$ > ` This north base line could be true north, magnetic north, or grid north. H=k0w14}slPZHZ:u_-XC]}>2FD8\70}@YC"/QRpP>eEF^fxFh ''LN =j*'U80 This angle is the difference between the north and the magnetic Using it is pretty simple: Place the center over the point on the map youre using to determine which azimuth youre going to travel on, square the protractor to a. Considerations for Downhole Survey Azimuths The conversion (add or subtract) is governed by the direction of the magnetic-north prong relative to that of the north-grid prong. This means how to measure a direction - or azimuth - on your map and HMk@azp*@4X6{ I really hate to stir the pot but--. Report Date: 071-COM-1016 Convert an Azimuth Status: c. Grid Convergence. Magnetic _____ 4) What is the method of intersection when a compass is unavailable? endstream That explanation on drawing lines on the map is definitely very useful. For greater accuracy, the desired method of resection would be to use three or more well-defined locations. Web(a) To plot a magnetic azimuth on a map, first convert it to a grid azimuth (Figure 6-13). Back Azimuth and Backsighting Always align this line with the vertical lines on a map (Figure 6-9). To express direction as a unit of angular measure, there must be a starting point or zero measure and a point of reference These two points designate the base or reference line. hbbd``b`@) Dl;@D#` n%"~1Ll %` ( The azimuth is the most common military method to express direction. We used the earlier GPS's called sluggers. DIRECTION B181996 STUDENT HANDOUT - USMC OFFICER endobj Convergence is the difference between geodetic north and grid north. When an azimuth is plotted between point A (beginning) and point B on a map, it is called a grid. When using the map and compass method (Figure 6-18). <>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI] >>/MediaBox[ 0 0 612 792] /Contents 4 0 R/Group<>/Tabs/S/StructParents 0>> xUM0#hWgK G!(l9Rq[L1yfzYjz`W^7]>o_vz{a}Kt;8X 9ngA>A))(&J%qWI H-5dEC{,O^fa< nY&j!5bA w}C|3nq{ceUxc0P }*%9M4.e$$""U rQ1md6G+ a :mB>8a/7Z's?9hd-VyH"a.9QEhd?SGq9~*OO.fM&:CEY) Theyre not essential for shooting an azimuth or bearing (from hear on out referred to as either a Grid Azimuth (GAZ) or Magnetic Azimuth (MAZ)), but they are very, very useful is plotting (determining) positions on a map to within various levels of accuracy (read distance from the actual object being plotted). How do you convert Magnetic North to grid north? MSL201L07 Intermediate Map Reading Quiz.docx When measuring azimuths on a map, remember that you are measuring from a starting point to an ending point. 2287 0 obj <>/Filter/FlateDecode/ID[<01E97BD82B4A724EA381572D5ADBF101><24C8F5536AE732469D3285819F05CE2D>]/Index[2282 15]/Info 2281 0 R/Length 48/Prev 360229/Root 2283 0 R/Size 2297/Type/XRef/W[1 2 1]>>stream 1800 0 obj <>stream Land Navigation 4 The shortest easterly or westerly G-M angle. When I was taking a land nav course in the Army I was told this would vary depending on what part of the world you were in. The G-M angle value is the angular size that exists between grid north and magnetic north. H1k0F{t'B8)-t*d_JS'>!'nh6z B)b|mxG>]LW]^~Hlqg}/JT~Cn~ v&-?OM. Azimuths UTM Grid North is said to be "X" number of degrees either east or west of True North. This value will be written in the map margin (in both degrees and mils) beside the diagram. Once the degree is in the center of the indicator, youre set. Therefore, b. E:ICHfO3di:z|sPKP#2~=u!3)_%BMk;"TVeWm9e4=5_5u=-8Cl6jY2*{d~[2fn3P7xkd. %PDF-1.5 % How do you calculate Grid North to magnetic north? b. Grid-Magnetic Angle. The computation of the grid correction angle or angle of convergence will require special mathematical techniques depending on the type of projection of the curved earth's surface on to the flat grid. 6 0 obj Simply refer to the conversion notes that appear in conjunction with the diagram explaining the use of the G-M angle (Figure 6-8). Map reading and the ability to navigate is a fundamental skill This listing indicates a grid convergence of 1o 00' 00". A grid correction converts azimuth readings between the True North systems and the specified grid system. With the rise of technology, true maps, compasses, and land nav will be a thing of the past. % Look up "LARS." It is an arc, indicated by a dashed line, that connects the grid-north and magnetic-north prongs. The angle of correction is the angle between the meridians of longitude and the Northings of the grid system at a specified point. They are certainly not parallel with one another and certainly not parallel with the central meridian. In this post, were going to look at the how and why of converting grid (or map) azimuths/bearings to magnetic azimuths/bearings and vice versa. The azimuth or bearing is a line you draw through the four cardinal directions. Proceed as follows: a. Orient the map using a compass or by terrain association. Your %PDF-1.5 a. yg! $RC ku,B:d k5(*(ig0;5o!` QuM^4oG-9Q[bG}1g_iulBewm|J""F]||0 (4) Convert the magnetic azimuth to grid azimuth. If you are just navigating to hunt or recreate I would recommend not getting wrapped around the axle on this. Converting to a grid azimuth on a map. 1 0 obj Webc. The military protractor, GTA 5-2-12, contains two scales: one in degrees (inner scale) and one in mils (outer scale). The magnetic declination correction is the angle between the horizontal component of the earth's magnetic field lines and the lines of longitude. How to convert magnetic azimuth to grid azimuth, The how to convert magnetic azimuth to grid azimuth is a question that may be asked in the context of travel. How to convert magnetic azimuth to grid azimuth, The how to convert magnetic azimuth to grid azimuth is a question that may be asked in the context of Geomagnetism a. endstream If you have a map and a compass, the one of most interest to you will be between magnetic and grid north. words, an object moved in the direction of 223 degrees (Southwest On medium-scale maps, the declination information is shown by a note in the map margin. WebThe University of Akron : YOU BELONG HERE! (2) To plot an azimuth from a known point on a map (Figure 6-7), (a) Convert the azimuth from magnetic to grid, if necessary. Have students construct an azimuth-back azimuth line through each point until each end of the line hits a map margin. To start, what is your goal? stream Draw an arrow pointing east (azimuth of 90) for an arbitrary borehole azimuth reference. endstream endobj startxref (6) Move to a second known point and repeat steps 1, 2, 3, 4, and 5. If you are surveying or doing something other than land nav for hunting, this may matter. Declination is the angular difference between any two norths. How To Convert Magnetic Azimuth To Grid Azimuth _:-"U-?Y E_t=++k This is a direct result of the grid north lines being parallel with each other. Web1995 G-M ANGLE MILS) 5040 TO CONVERT A MAGNETIC AZIMUTH TOA GRID AZIMUTH ADD G-M ANGLE 0-95 ro GIVE A STANDARD REFERENCE ON THIS SHEET TO NEAREST 100 METERS tifying 100,000 meter point lies: ICAL grid line to LEFT LARGE figures labeling e top or bottom margin. What north and how? endobj This is a direct result of the geodetic north lines converging. To convert a magnetic azimuth to grid azimuth, subtract G-M angle. If you have a magnetic azimuth of 270 degrees, and the G-M angle is 8 degrees, your grid azimuth will be 262 degrees. % Theyll either have tick marks on them that you can use to provide your own grid (as I have done and commenters have suggested (Tip: Use very thin map marking pens and dont use red ink red disappears when using a red light) or complete grid lines. 260 180= 80 Step 2. Did Billy Graham speak to Marilyn Monroe about Jesus? All the convergence angles west of the Central Meridian are negative. Who's going to be the first hunting 'celebrity' or Youtube personality to put their foot down and stop using cellular cameras? (c) Convert a magnetic azimuth when the G-M angle is greater than the magnetic azimuth (Figure 6-15). This value is expressed to the nearest 1/2 degree, with mil equivalents shown to the nearest 10 mils. This north base line could be true north, magnetic north, or grid north. Known= 270 mag 3. Converting azimuths with westerly G-M angle.