n Diagram
65 Magnetic North 20 degrees East 21 degrees west 0 degrees Declination Across Canada
66 CONVERTING BEARINGS Whenever you take a bearing from a map and want to follow it with a compass, you must take into account the magnetic declination. The same holds true when you want to plot a bearing taken from your compass, onto a map.
67 CONVERTING BEARINGS The declination for the searcher maps used by ESGSAR is 21 o West. During a search, bearings are always MAGNETIC. During a search, bearings given by the command centre (via radio and on taskings) include declination.
68 CONVERTING BEARINGS For West Declinations (ie. the Maritimes): To convert a grid bearing (taken from a map) to a magnetic (compass) bearing: Add Declination To convert a magnetic bearing (taken from a compass) to a grid (map) bearing: Subtract Declination
69 CONVERTING BEARINGS EXAMPLE: Converting grid (map) bearing to a magnetic (compass) bearing. Declination: 21 degrees West. Grid bearing: 60 degrees Magnetic bearing = Grid bearing + 21 Magnetic bearing = 81 degrees
70 CONVERTING BEARINGS EXAMPLE: Converting magnetic (compass) bearing to a grid (map) bearing. Declination: 21 degrees West. Magnetic bearing: 90 degrees Grid bearing = Magnetic bearing - 21 Grid bearing = 69 degrees
71 CONVERTING BEARINGS EXERCISE Convert the following bearings: 1. Declination: 21 o W 2. Declination: 21 o W Magnetic bearing: 264 o Grid bearing: 167 o Grid bearing:??? Magnetic bearing:??? 3. Declination: 21 o W 4. Declination: 21 o W Grid bearing: 69 o Magnetic bearing: 10 o Magnetic bearing:??? Grid bearing:???
72 CONVERTING BEARINGS EXERCISE ANSWERS 1. Declination: 21 o W 2. Declination: 21 o W Magnetic bearing: 264 o Grid bearing: 167 o Grid bearing: 243 o Magnetic bearing: 188 o 3. Declination: 21 o W 4. Declination: 21 o W Grid bearing: 69 o Magnetic bearing: 10 o Magnetic bearing: 90 o Grid bearing: 349 o
73 DETERMINING BEARINGS FROM A MAP To follow a route in the field between two points on a map, the direction (bearing) between these points must be determined first. This can be accomplished by using the compass as a protractor to determine the bearing.
74 DETERMINING BEARINGS FROM A MAP The following 5 steps outline the procedure for determining a bearing with a compass: 1. With a sharp pencil, lightly draw a line between the departure and destination points. 2. Align the long edge of the compass along the line with the direction of travel arrow point towards the destination point.
75 DETERMINING BEARINGS FROM A MAP 3. Holding the compass in this position, rotate the compass housing until the meridian lines on the base are aligned with the north-south grid lines on the map, with the orientating arrow pointing north. 4. Read the bearing on the compass housing at the index pointer. This is the grid bearing. 5. Add the declination(21) to the grid bearing to determine the magnetic bearing.
76 Determining A Bearing From the Map Line of Travel Drawn on Map Index Pointer Read at 14 (grid bearing) Meridian Lines = 35 Degrees Magnetic Bearing
77 DETERMINING BEARINGS FROM A MAP EXERCISE Using the provided Searcher Map, determine the magnetic bearings for the following: A. From SCHOOL to ESGSAR BUS. B. From ESGSAR BUS to CAMP. C. From CAMP to waypoint #4. D. From waypoint 4 to SCHOOL. E. From ESGSAR BUS to SCHOOL.
78 DETERMINING BEARINGS FROM A MAP ANSWERS A) SCHOOL to ESGSAR BUS: 20 magnetic B) ESGSAR BUS to CAMP: 110 magnetic C) CAMP to Waypoint #4: 262 magnetic D) Waypoint 4 to SCHOOL: 274 magnetic E) ESGSAR BUS to SCHOOL: 200 magnetic
79 TAKING A COMPASS BEARING To determine the bearing of a particular object or direction in the field, perform the following steps: 1. Hold the compass steady and level at chest height, and point the direction of travel arrow in the direction of an object or in the direction that you want to travel. This can also be done using the sighting mirror. 2. Rotate the compass housing until the orienting arrow is under and parallel to the coloured end of the magnetic needle (Put the Red in the Bed). 3. The bearing is now set on the compass and may