MAP READING & RESECTION
Conditions: You have a requirement to determine your current location during tactical operations.
Understanding This Task
Resection is the method of finding your unknown location by shooting back-azimuths to two or more known points and plotting where the lines intersect on the map.
Key conversion: Magnetic azimuth to grid azimuth requires applying the G-M angle. Then convert to back-azimuth (+/- 180 degrees).
100% accuracy required on terrain features, colors, and contour lines.
Common NO-GO Mistakes
- Not applying G-M angle when converting azimuths
- Confusing spur and ridge, or draw and valley
- Wrong map color associations
- 6-digit grid accuracy required
Task Basis: 071-COM-1015, 071-COM-1000, 071-COM-1001
Video Resources
- 100% accuracy on terrain features, colors, and contour lines.
- Resection = back-azimuths from 2+ known points.
- Apply G-M angle when converting magnetic to grid azimuth.
PERFORMANCE MEASURES
0/7 GO- 1
Determine location using resection
- Orient map on flat surface using compass.
- Identify at least 2 well-defined points on ground and mark on map.
- Determine magnetic azimuth to each point.
- Convert magnetic azimuth to grid azimuth (apply G-M angle).
- Convert to back-grid azimuth (+/- 180 degrees).
- Plot back azimuths using protractor. Draw lines.
- Intersection of lines = your location.
- Determine 6-digit grid coordinates.
- 2
Identify major terrain features (5)
- Hill, Saddle, Valley, Ridge, Depression
- 3
Identify minor terrain features (3)
- Draw, Spur, Cliff
- 4
Identify supplementary terrain features (2)
- Cut, Fill
- 5
Identify map colors (6)
- Blue = water/hydrography
- Black = cultural (manmade) features, labels
- Green = vegetation with military significance
- Brown = relief features, elevation, contours
- Red = cultural features on older maps
- Red-brown = cultural + relief on red-light readable maps
- 6
Identify contour line types (3)
- Index, Intermediate, Supplementary
- 7
Identify 22 topographic symbols
From the Ranger Handbook (TC 3-21.76)
Supplementary context — not tested directly, but builds deeper understanding.
Terrain Features in Tactical Operations: The Ranger Handbook uses terrain features throughout its tactical guidance — understanding them is not just a test requirement but a fundamental Ranger skill:
- ORP placement (Ch. 7, para 7-15): The objective rally point typically lies 200-400 meters from the objective, or at a minimum one major terrain feature away.
- Dissemination (Ch. 7, para 7-32): After reconnaissance, the element moves to a position at least one terrain feature or one kilometer away to disseminate information.
- Terrain models (Ch. 2, para 2-27): During planning, the terrain model highlights prominent terrain features the patrol encounters during movement. A second model of the objective area is prepared for briefing actions on objective.
- Withdrawal (Ch. 7): After contact, the PL moves the platoon to a safe location no less than one kilometer or one terrain feature away from the objective.
Map Reading Reference: The Ranger Handbook references TC 3-25.26 (Map Reading and Land Navigation) as the primary manual for detailed map reading procedures, resection, intersection, and terrain association techniques.
Source: TC 3-21.76, Chapters 2 and 7, April 2017