Date post: | 17-Dec-2015 |
Category: |
Documents |
Upload: | ellen-thornton |
View: | 213 times |
Download: | 0 times |
1FieldLN.PPT
LAST REVISED: 9 JULY 2008 Citizens Serving Communities
Field Expedient Direction Finding
Developed by the
National Emergency Services Academy
2FieldLN.PPT
LAST REVISED: 9 JULY 2008 Citizens Serving Communities
Objectives
• Learn various methods to determine direction without the use of a compass– Stick and shadow method– Watch method– Sun– Stars – Natural
3FieldLN.PPT
LAST REVISED: 9 JULY 2008 Citizens Serving Communities
Stick and Shadow
• The sun rises in the east and sets in the west- but not quite…– Rarely does the sun rise directly in the
those directions (90 or 270 degrees)– You can still use the shadow tip
method to determine direction– Start by finding a stick you can drive
in or prop up on the ground.
4FieldLN.PPT
LAST REVISED: 9 JULY 2008 Citizens Serving Communities
1. Place a stick or branch in the ground at a level spot where a distinctive shadow will be cast.
Shadow Tip Continued
2. Mark the shadow tip with a stone, twig, or other means. This first shadow mark is always west.
5FieldLN.PPT
LAST REVISED: 9 JULY 2008 Citizens Serving Communities
Shadow Tip Continued
3. Wait 10 to 15 minutes until the shadow tip moves a few inches. Mark the new position of the shadow tip in the same way as the first.
4. This second shadow mark is always east. Draw a straight line through the two shadow- tip marks to obtain an approximate west- east line.
6FieldLN.PPT
LAST REVISED: 9 JULY 2008 Citizens Serving Communities
Shadow Tip Continued
Now, to determine your north- south line, stand with the first mark (west) to your left. The other directions are north to the front, east to the right, and south behind you.
Remember- the stick must be vertical in the ground.
7FieldLN.PPT
LAST REVISED: 9 JULY 2008 Citizens Serving Communities
The west part of the east-west line is 0600 hours and the east part is 1800 hours. The north-south line becomes noon and the shadow of the stick becomes the hour hand.
Tell time with your shadow?
8FieldLN.PPT
LAST REVISED: 9 JULY 2008 Citizens Serving Communities
Shadow Tip Continued
• Accuracy varies depending on latitude and time of day
• Early morning and late evening are the least accurate; Close to noon is the most accurate
• The closer you are to the equator- the more accurate
• If readings are taken throughout the day, errors tend to cancel each other out
9FieldLN.PPT
LAST REVISED: 9 JULY 2008 Citizens Serving Communities
Watch Method
• Must have a non-digital watch• Not as accurate as shadow stick methodIn the northern hemisphere:
1. Hold the watch with the hour hand pointing to the sun
2. Imagine a line running through the 12 and true south is midway between the hour hand and the 12.
10FieldLN.PPT
LAST REVISED: 9 JULY 2008 Citizens Serving Communities
Star Method
At night, you can find north by locating the North Star, Polaris. First, find the big dipper. The last two stars of the dipper’s cup point directly at Polaris about 5 times the distance between those two stars. Facing Polaris, you are looking north with east on your right and west on your left.
12FieldLN.PPT
LAST REVISED: 9 JULY 2008 Citizens Serving Communities
Other Clues…
• Not precise- and it takes practice, but…– Plants generally grow towards the sun– Moss often grows on the side away from the sun or
on the damper side of the tree but can be influenced by other factors
– Leaves on trees usually thicker on the sunny side– The rings of a tree stump are usually closer together
on the side closest to the poles
13FieldLN.PPT
LAST REVISED: 9 JULY 2008 Citizens Serving Communities
Make Shift Compass
• A needle from a sewing kit can be fashioned into a makeshift compass
• Magnetize the needle by rubbing it with silk or a magnet
• Hang with a thread to let the needle point to magnetic north
• You could also float it on some cork or similar material
14FieldLN.PPT
LAST REVISED: 9 JULY 2008 Citizens Serving Communities
• These presentations were made by the National Emergency Services Academy for the purpose of advancing, refreshing, or reviewing information for search and rescue training.
• Products shown are for illustration purposes only. The National Emergency Services Academy, Civil Air Patrol, or the United States Air Force does not endorse, guarantee, or recommend any specific company, service, business, or product.
• Presentations are designed to be used with qualified instructors familiar with your local area.