compass basics (jan 08) compressed 2

7/29/2019 Compass Basics (Jan 08) Compressed 2

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Map & Compass so easy a

caveman can do it!


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Compass BasicsOpening Comments

Terms of a compass

Boxing a needle

Get a bearing (you to a point)

Get a bearing (a point to you)

Orienting a map

Get a bearing on a map (from you to a point)

Get a bearing on a map (from a point to you)

Note: We will do practice exercises very slowly


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Demonstrate effects of metal on compass Note: There are many ways to teach map and compass. For the

purpose of this course, there is only one way (as given in yourcourse handout).

Every person in this course needs to learn Map & Compass. People

have become separated from friends and loved ones in thewilderness. Everyone who goes out in the wilderness needs to havebasic Map & Compass skills.

Do not think that a GPS will save you in the wilderness. Good GPSskills and great mapping skill go together hand-in hand.

Bring compass that the course provides !!!

Do not jump ahead during the lecture

let me walk you througheach slide!

Opening Comments


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Map & Compass Terms

Bearing The direction of a point relative to yourposition.

Declination The angular difference betweenTrue North and Magnetic North on the surface of

the earth (once you orient your map, you donthave to worry about declination again).

True North - Your map is based on True North(or Grid North). Envision a north axis (top) of the

earth as it spins, or North Pole. See next slide. Magnetic North The red end of your compassneedle points to Magnetic North. See slide afternext.


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Super-imposed Grid Lines showing

Grid North or True NorthGrid North here


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Magnetic North - determined that the average position of the North Magnetic Pole in 1994was located on the Noice Peninsula, southwest Ellef Ringnes Island, at 78.3 degrees North,104.0 minutes West. The yearly motion of the pole has increased, and is now 15 kilometers

per year. Geological Survey of Canada

True Northgrid line


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Needle

(red end)outside ofbox

Boxing a needle

(This displays a needle not boxed)


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Needle(red end)boxed

Boxing a Needle - (This displays a boxed needle)

Big note Sometimes you will box the needle by moving your feet,sometimes by moving the compass dial, and sometimes by moving themap.

Your bearing isread here: 320 -(note the white lineunder the number)


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Big Concept How to box a needle !!!I will demo first, then the next slides will walk you thru it.

A. Demo how to hold compass and view adistant object

Demo how to hold a compass at waist level and

adjust dial to box compass (used when getting abearing from you to a distant point).

B. Demo how to hold a compass at waist leveland box needle by moving feet (used when

setting a bearing on a compass and determininga direction of travel).

(give me a bearing (1 thru 360 )


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1st Exercise Find the bearing from you to a mountain peak in thedistance.

1. Hold compass up and point Direction of Travel arrow at (areato be named):

2. Bring compass down to waist level. Make sure compass islevel so that the needle floats freely. Box arrow by moving thedial:

3. Example of not boxed :

4. Read your bearing at the Bearing Index Point

This is the Direction of Travel arrow.

Note the small triangle on the tipcenter this on the peak !!!

Not boxed

Move dial tobox as shown

Bearing Index Point(White line under N)


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2nd Exercise someone tells you to follow abearing of 90 or 270 from your current position.

1. Stand up.

2. Hold compass at waist level and keep compass level.

3. Move the dial on your compass until 90 (or E) appears atthe Bearing Index Point.

4. Box the needle by moving your feet to the left or right.

1. Stand up.2. Hold compass at waist level and keep compass level.

3. Move the dial to 270 (or W) at the Bearing Index Point

4. Box the needle by moving your feet to the left or right.


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Step 1. Align Directionof Travel Arrow and

Arrow Box oncompass.

Align Direction ofTravel arrow andArrow Box to bepoint in samedirection by movingthe compass dial.

Orienting a map(Student Exercise)


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Step 2.Aligncompasson side ofmap asshown

(side is

highlightedin greenon yourmap).

Note: Needle isnot boxed at thistime.

Orienting a map cont.


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Step 3. Grabcorner of mapand move left

or right to boxneedle. Note: Needle is

boxed.

Orienting a Map cont.

1st Big Visual Check

all 3 arrows arepointing in samedirection


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Step 4.Grab cornerof map and

move untilmagneticneedle ofcompass isabout 13 tothe right ofthe ArrowBox. Themap is noworiented.

2nd Big Visualcheck: themagnetic arrowshould be to the

right of the boxarrow in the samemanner as thediagram below

Important

Your Map is noworiented for declination


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Obtain a bear from you to a peak

(on a map)

Orient your map as per previous exercise.

Importantafter you orient your map,do not move your map !!! We orient the

map to adjust for magnetic declination.Features on the map are now oriented toyou as they are on the ground. Do notpick up the map and walk around with ittrying to find things.

Follow next slides.


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Obtain a bear from you to a peak (on a map)

1. Draw a line from yourposition to your Point ofInterest # 1 on map 2. Aligncompass on line as shownwith Direction of Travelarrowpointing at Point of

Interest.

Point of interest Direction Arrowalways pointstowards Point of Interest

Note: needle isnot boxed yet

You are here


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Obtain a bear from you to a peak (on a map) cont.

4. Read your Bearing at yourBearing Index Point thebearing is 290 from you to

the peak. (a little inaccurateas pictured).

3. Rotate dial to box needle


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Last concept - Obtain a bear from a peak to you(on a map)

1. Draw a line from yourPoint of Interestto your

position. 2. Align compasson line as shown withDirection of Travel arrowpointing at your position

3. Rotate dial to boxneedle, as shown

4. Read your Bearing atyour Bearing Index Pointthe bearing is 110 fromthe peak to you.

Bonus

Based on the reading from the previous slide, how can youdetermine the 2nd bearing without putting the compass on the map?


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Questions

Question: If the bearing from you to a peak is 200, what is thebearing from peak to you?

Answer - 20. If the bearing to the peak is greater than 180,

subtract 180. If the bearing is less than 180, then add 180 tothe bearing (Look at your compass to get a visualization)

Question: What is the best way to find where you are on amap?

Answer: Always know where you are at ! Track yourmovement on the map from the moment you park yourcar. Do not try to hike for a few hours and figure thingsout later.


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Advanced PracticeTrianglization - Locating yourself by sighting 3 points

(without using a GPS).

We will not demonstrate in this class (field exercise only). Orient your map on the ground. Must identify 3 good points of reference, widely separated. Next slide will

demonstrate.

Standing up and using the compass to sight on each of the reference points,determine bearing from you to each reference point/peak. Use straight edge and compass to draw a line from each peak/reference

point using those bearings. Note: You must put the straight edge on thepeak (with the Direction of travel arrow pointing at the peak) and box thearrow with the bearing you got for that peak/reference point.

A triangle (as shown in next slide) will form where the 3 bearings intersect. You are located somewhere within that triangle. The more peaks that you sight and add, the smaller the triangle will become.


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Trianglization


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The 3 Biggest Secret to Map & Compass

2. Practice3. Practice

1. Practice

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