Navigation

• What is a compass?

  • A compass is a lightweight magnet, generally a magnetized needle, on a free rotating pivot. This allows the needle to better react to nearby magnetic fields. Since opposites attract the southern pole of the needle is attracted to the Earth's natural magnetic north pole.

• What is the magnetic declination in general? What is it in San Ramon?

  • Magnetic declination, or magnetic variation, is the angle on the horizontal plane between magnetic north and true north. This angle varies depending on the position on the Earth's surface and changes over time. In San Ramon, it is -12.86 (West).

• How do you orient a map?

1. Lay your map out on a relatively flat, smooth surface

2. Turn your compass dial so that North is at the index pointer on top

3. Place your compass on your map with the edge of the base plate parallel to the north-south meridians [A (geographic) meridian (or line of longitude) is half of an imaginary great circle on the Earth's surface, terminated by the North Pole and the South Pole, connecting points of equal longitude, as measured in angular degrees east or west of the Prime Meridian] on the map. Notice the orienteering lines and direction-of-travel arrow are all parallel with the map lines

4. Turn the map and compass together until the compass needle is "boxed" in the orienting arrow (Red in the Shed)

5. Now, the map is oriented to the real world. If you know where you are on the map, you should be able to look in any direction and see the objects represented on the map in the same direction.

• How do find directions without a compass

1. Using a stick and two rocks…

- Take a stick and place it upright so you can see its shadow; the taller, the better

- Make sure the shadow is on clear, level ground

- Mark the ground at the edge of the shadow with something small like a pebble

- Wait 10 or 15 minutes then mark the edge of the shadow again

- Make a straight line between the marks; this is a rough East-West line

- The first mark is the West mark and the second mark is the East mark

2. Using two sticks at night

Lie down and drive one stick into the ground at eye level

- Drive a second, taller stick into the ground behind it so that the tips of the sticks line up with a bright star

- Watch the star for a few minutes; if it seems to move…

• • Up you are facing East

  • Down you are facing West

  • Right you are facing South

  • Left you are facing North