Thread: Navigation with compass and map

some notes for you @Myk...

Basics
Compass points at Magnetic
Bearing: a horizontal angle measured clockwise from north
Compass bearing + deviation = magnetic bearing
Magnetic bearing + variation = true bearing.
True Virgins Make Dull Companions, Add Whiskey (T, V, M, D, C, A, W)
True, Variation, Magnetic, Deviation, Compass, Add Westerly

Compass
Direction of travel arrow: on base plate
Orienting arrow: red arrow on base of dial
Orienting lines: parallel lines on base of dial

Orienting map with compass
Turn dial so that N is lined up with direction of travel arrow
Compass on map, long edge parallel to map N/S lines, dial N to map N
Turn map for mag. var.

Obtaining grid bearing from terrain
Direction of travel arrow at feature
Turn dial for mag. var.
Read bearing
Follow bearing, ensure mag. needle points to mag. var.

Obtaining grid bearing from map
Find pos on map
Compass on map, long edge toward destination
Direction of travel arrow at destination
Turn dial orienting lines parallel, dial N to map N
Read bearing
Turn yourself for mag. var.
Direction of travel arrow points at destination
Ensure mag. needle points to mag. var.

Identifying feature using grid bearing (known pos.)
Direction of travel arrow at feature
Turn dial so needle at mag. var.
Compass on map, long edge on pos., direction of travel arrow at feature
Turn base plate until orienting lines parallel (edge still on pos)
Feature will lie along long edge

Obtaining position by triangulation
Identify feature and take grid bearing (B)
Plot bearing on map. Turn base plate until orienting lines parallel (edge still on feature)
Position lies along the line
If not on known ridge, river etc, take second bearing (pref 90 deg.)
Three bearings: pos within triangle

Travel on a bearing
Compass horizontal, direction of travel arrow ahead
Turn yourself for mag. var.
Adjust direction so mag. needle keeps pointing at mag. var.

Back bearing
Differs 180 deg. from bearing you are using
Leave compass set on bearing
Turn yourself 180 deg, white end of needle pointing at mag. var.

Detour around obstacle (back bearing)
Leave compass set on bearing
Locate marker where course meets obstacle
Travel around obstacle
Take back bearing, do not adjust compass
If directly opposite marker, back on line of travel
Turn around till compass needle re-set on original bearing

Detour around obstacle (right angle)
Leave compass set on bearing
Turn L or R 90 deg, pace out distance
Turn back on original bearing, pace distance
Turn toward original line of travel (90 deg), pace distance
Turn back onto original bearing and continue