Magnetic Declination and Navigation

Magnetic Declination is the angle between True North and Magnetic North.

Compasses read Magnetic North because they are magnetic and align with the Earth's magnetic field.

To find Magnetic Declination, subtract or add the smaller number from Magnetic North if it is West or East of True North, respectively.

<p>Grid North is usually the closest to True North, but not as close as Magnetic North.</p> Signup and view all the answers

<p>Contour lines shaped like V's around a stream indicate the direction of stream flow. The point of the V shows the direction.</p> Signup and view all the answers

<p>A survey control mark is a specific point on a quadrangle map that provides the exact elevation of a location.</p> Signup and view all the answers

<p>There are 4 graticule tick marks on a quadrangle map.</p> Signup and view all the answers

<p>The sectors are named as follows: Sector 1 NW, Sector 2 N, Sector 3 NE, Sector 4 W, Sector 5 C (center), Sector 6 E, Sector 7 SW, Sector 8 S, Sector 9 SE.</p> Signup and view all the answers

<p>The graticule tick marks align with the latitude and longitude marks on the quadrangle map.</p> Signup and view all the answers

<p>The picture in the text shows a benchmark survey marker.</p> Signup and view all the answers

<p>A benchmark survey marker gives the exact elevation of a location.</p> Signup and view all the answers

<p>Because the elevation of mountains changes with tectonic plates.</p> Signup and view all the answers

<p>There are 4 graticule tick marks on a quadrangle map.</p> Signup and view all the answers

<p>The graticule tick marks divide the map into 9 different sectors.</p> Signup and view all the answers

<p>The sectors are: Sector 1 NW, Sector 2 N, Sector 3 NE, Sector 4 W, Sector 5 C for center, Sector 6 E, Sector 7 SW, Sector 8 S, Sector 9 SE.</p> Signup and view all the answers

<p>The graticule tick marks align with the latitude and longitude marks on the quadrangle map.</p> Signup and view all the answers

<p>The graticule tick marks show the latitude and longitude of a quadrangle.</p> Signup and view all the answers

<p>The map below is a quadrangle of East Amarillo.</p> Signup and view all the answers

<p>The graticule tick marks align with the latitude and longitude marks on the quadrangle map.</p> Signup and view all the answers

<p>A survey control mark gives the exact elevation of a location.</p> Signup and view all the answers

<p>The purpose of Magnetic Declination is to determine the difference between True North and Magnetic North.</p> Signup and view all the answers

<p>Magnetic North is the direction indicated by compasses, while True North is the actual direction of North.</p> Signup and view all the answers

<p>To calculate Magnetic Declination, subtract or add the declination angle from the bearing, depending on whether Magnetic North is to the west or east of True North.</p> Signup and view all the answers

<p>Magnetic North is usually the farthest from True North, while Grid North is usually the closest to True North.</p> Signup and view all the answers

<p>By observing the contour lines shaped like V's around a stream, the direction of stream flow can be determined based on the direction in which the point of the V is facing.</p> Signup and view all the answers

<p>If the contour line V points to the northwest, it indicates that the stream is flowing to the southeast.</p> Signup and view all the answers

<p>If the contour line V points to the southeast, it indicates that the stream is flowing to the northwest.</p> Signup and view all the answers

<p>The declination diagram is used to determine whether Magnetic North is to the west or east of True North, and to determine the number of degrees to subtract or add when calculating Magnetic Declination.</p> Signup and view all the answers

<p>The declination angle is added or subtracted from the bearing in order to adjust for the difference between Magnetic North and True North.</p> Signup and view all the answers

<p>The major difference between Magnetic North and True North is that Magnetic North is based on the direction indicated by compasses, while True North is the actual direction of North.</p> Signup and view all the answers