S-130 Map and Compass 4 — Questions and Answers
Question 1: On a topographic map, V-shaped contour lines pointing downhill (away from the summit) indicate what terrain feature?
- A drainage channel
- A spur or ridge (Correct answer)
- A cliff
- A plateau
Correct answer: A spur or ridge
V-shaped contours with the point of the V directed downhill (away from high ground) represent a spur or ridge extending outward from higher terrain.
Question 2: In the UTM coordinate system, what are the two components that define a location within a grid zone?
- Latitude and longitude
- Easting and Northing (Correct answer)
- Township and Range
- Azimuth and Distance
Correct answer: Easting and Northing
UTM coordinates use Easting (distance east of the zone's central meridian) and Northing (distance north of the equator) to pinpoint a location.
Question 3: Why should a wildland firefighter avoid placing a compass near a metal radio or vehicle when taking a bearing?
- Metal reflects sunlight and obscures the dial
- Metal objects can deflect the compass needle, causing an inaccurate reading (Correct answer)
- Radios emit heat that damages the compass
- Metal objects block the map's magnetic field
Correct answer: Metal objects can deflect the compass needle, causing an inaccurate reading
Ferrous metal and electronic devices create local magnetic fields that deflect the compass needle and produce false readings.
Question 4: A map legend shows a symbol that looks like a small tree cluster in green. What does this most likely represent on a USGS map?
- A designated campsite
- A forested or wooded area (Correct answer)
- A fuel break
- A wilderness boundary
Correct answer: A forested or wooded area
Green vegetation symbols on USGS topographic maps indicate areas with significant tree or shrub cover.
Question 5: What is 'triangulation' as applied to compass navigation in the field?
- Measuring the distance between two peaks
- Using bearings to two or more known landmarks to determine your unknown position (Correct answer)
- Dividing a section of map into triangles for area estimation
- Calculating slope angle using three contour lines
Correct answer: Using bearings to two or more known landmarks to determine your unknown position
Triangulation involves taking compass bearings to two or more identifiable landmarks and plotting the back bearings on a map to find where they intersect — your location.
Question 6: On a standard baseplate compass, what is the purpose of the orienting arrow (sometimes called the 'shed')?
- It indicates the direction of travel
- It is aligned with the compass needle to set and follow a bearing (Correct answer)
- It shows the magnetic declination correction
- It measures map distance
Correct answer: It is aligned with the compass needle to set and follow a bearing
The orienting arrow (housing arrow) is rotated to align with the magnetic needle once a bearing is set, allowing the traveler to follow the bearing without re-reading the dial.
Question 7: In wildland fire, terrain features that channel wind — such as chimneys and saddles — can be identified on a topographic map by looking for:
- Widely spaced contour lines
- Constrictions or low points between high ground (Correct answer)
- Blue water feature symbols
- Dashed supplementary contour lines only
Correct answer: Constrictions or low points between high ground
Saddles (low points between peaks) and drainage channels (chimneys) appear on topo maps as low points flanked by higher contour rings — classic wind-channeling terrain.
S-130 Map and Compass 4
On a topographic map, V-shaped contour lines pointing downhill (away from the summit) indicate what terrain feature?