PS PS Map Projections & Cartography 2 — Questions and Answers
Question 1: What is the angular difference between grid north and true (geodetic) north called?
- Meridian convergence (mapping angle) (Correct answer)
- Magnetic declination
- Grid variation
- Azimuth correction
Correct answer: Meridian convergence (mapping angle)
Meridian convergence (also called the mapping angle or gamma) is the angular difference between true north and grid north at a given point.
Question 2: Which contour line is drawn heavier (darker) to aid map reading and appears at every fifth contour interval?
- Index contour (Correct answer)
- Intermediate contour
- Supplementary contour
- Depression contour
Correct answer: Index contour
Index contours are drawn in a heavier line weight at every fifth contour interval and are typically labeled with their elevation.
Question 3: What symbol on a topographic map indicates a closed depression (a low point surrounded by higher terrain)?
- Hachured contour lines (Correct answer)
- Dashed contour lines
- Blue shading
- Dotted contour lines
Correct answer: Hachured contour lines
Depression contours are drawn with hachure marks (short tick marks) pointing inward toward the low point to distinguish them from normal contours.
Question 4: What is the Universal Transverse Mercator (UTM) system's standard zone width in degrees of longitude?
- 6 degrees (Correct answer)
- 3 degrees
- 9 degrees
- 12 degrees
Correct answer: 6 degrees
The UTM system divides the world into 60 zones, each spanning 6 degrees of longitude, from 80°S to 84°N latitude.
Question 5: What is the false easting assigned to the central meridian in each UTM zone to avoid negative easting values?
- 500,000 meters (Correct answer)
- 1,000,000 meters
- 250,000 meters
- 0 meters
Correct answer: 500,000 meters
UTM assigns a false easting of 500,000 m to the central meridian of each zone so that all points within the zone have positive easting values.
Question 6: What is the map scale classification for a map with a representative fraction of 1:1,200?
- Large scale (Correct answer)
- Small scale
- Medium scale
- Micro scale
Correct answer: Large scale
Maps with representative fractions of 1:600 to 1:12,000 are considered large-scale maps, with 1:1,200 being among the most detailed used in surveying.
PS PS Map Projections & Cartography 2
What is the angular difference between grid north and true (geodetic) north called?