A bare bone ppt on Triangulation oldschoolyard.com

2. Triangulation:
to locate yourself on a map by comparing your
topographic map to what you are looking at, and
identifying terrain features that you are sure you
can recognise for real and on the map

3. Position Fixing – Triangulation or
Resection
1. Used when you’re
unable to fix your
position
2. Find 3 prominent
features
3. Take a magnetic
bearing of the
features
4. Convert these to a
grid bearing
5. Change to a back
bearing
6. Plot all bearings on
map
7. Your position is where
the back bearings
intersect.

4. Features
Magnetic bearings
Grid bearings
Back bearings
Draw bearings on your map
Triangle of Error (GR)

5. Finding
Myself
Goes
Better
Drawing
Triangles

6. Features
• Identify Three easily recognisable features that
you can see in real life and on the map
• The further apart the 3 features the better
• for each feature, it helps if there is an exact
point you can take a bearing off

7. Magnetic Bearings
• Your bearings must be taken as precisely as
possible from each feature
• Using an exact point like a cliff edge or mountain
peak helps to maintain accuracy

8. Grid Bearings
• find the Magnetic Variation for your area
• Usually subtract this number from your
Magnetic Bearings to create Grid Bearings (for
each bearing!)
• GMAMGS when Mag North is West of True
North (like it is for us in SW WA)

9. Back Bearings
• Create a back bearing by finding the exact
opposite direction (in degrees) of you Grid
Bearings (do this for each grid bearing)

10. Drawing the Back Bearings
• As accurately as possible draw a line on your
topographical map along the back bearing (for
each back bearing)
• Make sure you start the line at the point your
compass originally aimed at

11. Triangle of Error
• You should be left with
three lines that
intersect in a triangle
• This is the Triangle of
Error and you now
know your position is
within this triangle!
• Give a 6 digit GR for
your final answer
All images sourced from Google image search and are used for education purposes only