Archive for the ‘Map Orientation’ Category
Map Orientation!
Map/Compass/Ground Orientation!
A needed preliminary step to map/ground association is to orient the map with the lay of the land. After orientation, if you plot your location on the map, and while doing it see a hill top 2000 yards to the northwest, you should be able to look up and see that same hill top to your right-front at 2000 yards.
The method used to orient the map with the ground depends on what you’re doing. If all you want is a quick analysis, determine north (compass) and point the top of your map in that direction, and map is generally oriented. But, if you’re intention is to determine/plot directions or azimuths on the map and accuracy is critical, the method used should be exact, deliberate and allow no errors:
- Place the map on a flat surface;
- Open compass and place it (straightedge) parallel with a North/South grid-line.
- Keeping the compass aligned, as directed above, carefully rotate the map/compass (together) until the magnetic arrow is below the fixed black index line of the compass (almost oriented);
- To further compensate for the small Grid/Magnetic (GM) angle change, rotate map and compass in the direction of the magnetic arrow in the declination diagram. Whether movement is right or left, rotate the map/compass that small amount (degree/mils) indicated by the G/M angle. The number of degrees/mils of rotation will be reflected under the fixed index line of the compass.
The map and compass are now oriented in accordance with map’s Declination Diagram.