Compass Resection: Pinpoint Your Location
In groups of three, students learn to work out where they are by taking bearings on two or three visible landmarks and drawing back bearings on the map. It is a real backcountry navigation skill practiced around campus while moving between stations.
How to play
- Choose 4 numbered observation points, each with at least three clear landmarks that appear on the map (a tower, a building corner, a light pole, a lone tree).
- Take 4 minutes to teach the technique: point the compass at the landmark, read the bearing, add or subtract 180° and draw the line on the map from that landmark.
- Form groups of three with three jobs: bearing taker, plotter and checker; rotate jobs at each point.
- Groups jog to the first point, take two bearings, plot the lines and mark an X where they cross (about 3 minutes per point).
- After each point, the checker takes a third bearing to verify; if the three lines form a small triangle, the fix is good.
- After all 4 points, each group compares its X marks with the answer map and measures each error in meters.
Rules
- Stand at least 2 m (6 ft) away from light poles, fences and phones so they don't pull the needle.
- The group with the smallest total error across the four points wins.
- Travel between points on paths and never cross areas with traffic.
Variations
Easier
Use just one landmark plus a known linear feature (a path or a wall) to fix the position.
Standard
Two bearings to fix the position and a third to check at each point.
Harder
Don't name the landmarks: the group must identify them on the map on its own.
Adaptations
- Limited mobility: place observation points in accessible areas and let the student take the plotter or checker role.
- Visual impairment: use a compass with large markings and an enlarged map, with a partner describing the landmark.
- Advanced level: add magnetic declination correction and require an error under 20 m (65 ft).
Learning goals
- Take accurate compass bearings on visible landmarks.
- Calculate the back bearing and plot it correctly on the map.
- Appreciate how this technique helps in a real situation of being lost.
Equipment for a class of 25
- topographic maps: 9
- compasses: 9
- pencils: 9
Teacher tip
The most common mistake is forgetting to add or subtract 180° when plotting; have students write it down before drawing the line. Bring spare pencils and erasers.
PatioLab has "Compass Resection: Pinpoint Your Location" and 2499 more activities ready to drag into your lesson and run from your phone in the gym.
More activities like this
More main activities for High School
1-2-3-2-1 Running Pyramid Intervals
An interval workout where the fast segments build from 1 to 3 minutes and back down, with half that time as jogging recovery.
1-on-1 Self-Pass Volleyball
One-on-one games on narrow 10 x 20 foot courts where each player must self-pass before sending the ball over.
10-20-30 interval running in pairs
The 10-20-30 method strings together 30 seconds of easy jogging, 20 at a moderate pace and 10 at top speed, in five-minute blocks.
1v1 Ball Volley Matches
1v1 ball volley: singles games on a small court with a low net, hitting the ball over the net and allowing one bounce.
2-on-1 Fast Break with a Chasing Defender
Two attackers push a fast break against a defender waiting at the basket while a second defender chases from behind with a few yards' head start against them.
2-on-1 Through Three Defensive Zones
Pairs of attackers cross the court through three zones, each with a defender who cannot leave it, and finish with a shot on goal.