If you moved left you should add the angle between grid and magnetic; if you moved right, you should subtract. How do you convert Magnetic North to grid north? endobj If it were the other way around (adding the GM angle instead of subtracting in a western state) you would just be INCREASING the difference between your grid and magnetic orientations, rather than making them the same. Declination diagram with arbitrary line. (3) Measure the magnetic azimuth to one of the known positions from your location using a compass. All the convergence angles east of the Central Meridian are positive. Using LARS, convert to a grid azimuth. (2) Locate and mark your position on the map. For a better experience, please enable JavaScript in your browser before proceeding. b. e. Applications. True North. When using the map and compass method. Draw an arrow pointing east (azimuth of 90) for an arbitrary borehole azimuth reference. (3) Lay a straight edge on the map with one end at the users position (A) as a pivot point; then, rotate the straightedge until the unkown point is sighted along the edge. True north is usually represented by a star (Figure 6-1). Thus we ADD the variation (12 degrees) to give the Grid Bearing [A rhumb line appears as a straight line on a Mercator projection map. 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). ( d) To measure an azimuth, turn your entire body toward the object and point the compass cover directly at the object. When using the map and compass method (Figure 6-18). TERMINAL LEARNING OBJECTIVES 2. ENABLING With this in mind, the following procedure is suggested: True North azimuth will equal 90; Magnetic azimuth will equal 90 plus/minus declination; Grid azimuth will equal 90 plus/minus grid convergence. 9 0 obj<>>>/MediaBox[0 0 612 792]>> 92 301 w 30 401 N 91 201 28 40' 91 201 25 40'. WebThe University of Akron : YOU BELONG HERE! Personally, I prefer maps that use the MGRS (Military Grid Reference System) which is similar to the UTM, but scaled in 1:25,000 & 1:50,000, which is what I learned in during active duty. SOUTH IS 180. This is the grid direction line (azimuth). Luckily, with the use of WebStep 1. endstream endobj startxref The John A. Dutton Institute for Teaching and Learning Excellence is the learning design unit of the College of Earth and Mineral Sciences at The Pennsylvania State University. Draw an arrow for Grid North using an exaggerated angle east or west of True North showing the grid convergence angle (be sure of the sign convention of the grid convergence value used, for example does a west convergence angle put Grid North west of True North or visa versa?). Did Billy Graham speak to Marilyn Monroe about Jesus? A line from 0 to 180 degrees is called the base line of the protractor. <>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI] >>/MediaBox[ 0 0 612 792] /Contents 10 0 R/Group<>/Tabs/S/StructParents 1>> This angle is the difference between the north and the magnetic When using it. Figure 6-14. (3) Lay a straightedge on the map using a known position as a pivot point. This is easy to remember. Converting Magnetic Azimuth to grid Azimuth | Rokslide Forum 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. Determine the grid coordinates to the desired accuracy. The magnetic north is usually symbolized by a line ending with half of an arrowhead (Figure 6-1). to arrive at the starting point.