GIS Cartography and Visualization 3 — Questions and Answers
Question 1: What is a 'datum shift' in GIS cartography?
- A change in map projection
- A positional offset between features referenced to different geodetic datums (Correct answer)
- A change in map scale
- An error in digitizing coordinates
Correct answer: A positional offset between features referenced to different geodetic datums
A datum shift occurs when coordinates are transformed between two datums (e.g., NAD27 to NAD83), causing positional offsets of meters to hundreds of meters.
Question 2: Which type of map is most appropriate for showing the movement of goods between cities?
- Choropleth map
- Flow map (Correct answer)
- Dot density map
- Cartogram
Correct answer: Flow map
Flow maps use lines of varying width or direction to represent the volume and direction of movement between geographic locations.
Question 3: What does CMYK stand for in map printing?
- Cyan, Magenta, Yellow, Black (Correct answer)
- Contrast, Mix, Yield, Key
- Color, Mode, Year, Kind
- Cyan, Maroon, Yellow, Khaki
Correct answer: Cyan, Magenta, Yellow, Black
CMYK (Cyan, Magenta, Yellow, Key/Black) is the subtractive color model used in professional map printing.
Question 4: A cartogram distorts geographic space to be proportional to:
- Population or another thematic variable (Correct answer)
- True physical distance
- Elevation
- Time zones
Correct answer: Population or another thematic variable
A cartogram replaces true geographic area with a statistical variable such as population, GDP, or disease cases.
Question 5: Which contour line connects points of equal elevation on a topographic map?
- Isohyet
- Isobar
- Isohypse (Correct answer)
- Isochrone
Correct answer: Isohypse
An isohypse (topographic contour line) connects all points at the same elevation above a reference datum.
Question 6: What map element provides the ratio between map distance and real-world distance?
- North arrow
- Legend
- Scale bar (Correct answer)
- Neatline
Correct answer: Scale bar
A scale bar is a graphical representation of the ratio between distances on the map and corresponding distances on the ground.
Question 7: Which projection type is commonly used for navigational charts because it makes rhumb lines appear as straight lines?
- Albers Equal-Area
- Mercator (Correct answer)
- Azimuthal Equidistant
- Sinusoidal
Correct answer: Mercator
The Mercator projection preserves angles (conformal) and represents lines of constant compass bearing (rhumb lines) as straight lines.
GIS Cartography and Visualization 3
What is a 'datum shift' in GIS cartography?