CFP Geographic Information Systems 3 — Questions and Answers
Question 1: A fisheries manager is combining a benthic substrate layer with a water depth layer to identify spawning habitat. What GIS operation is being used?
- Map overlay (intersect/union) (Correct answer)
- Network analysis
- Point interpolation
- Temporal joining
Correct answer: Map overlay (intersect/union)
Map overlay operations like Intersect or Union combine multiple spatial layers to produce composite habitat classifications based on multiple attributes.
Question 2: What does NDVI (Normalized Difference Vegetation Index) derived from satellite imagery indicate in riparian buffer assessments?
- Water turbidity levels
- Vegetation greenness and density (Correct answer)
- Stream flow velocity
- Sediment load estimates
Correct answer: Vegetation greenness and density
NDVI uses near-infrared and red bands to quantify vegetation density and health, useful for assessing riparian buffer condition.
Question 3: Which GIS approach is used to determine fish passage barriers by identifying stream reaches where gradient exceeds a threshold value?
- Kernel density mapping
- Longitudinal profile analysis with attribute queries (Correct answer)
- Thiessen polygon generation
- Land cover reclassification
Correct answer: Longitudinal profile analysis with attribute queries
Longitudinal profile analysis extracts stream gradient from DEMs and attribute queries flag reaches exceeding barrier thresholds for fish passage.
Question 4: In GIS telemetry studies, what statistical spatial method is most commonly used to estimate a fish's home range?
- Inverse Distance Weighting
- Kernel Density Estimation (KDE) (Correct answer)
- Ordinary Kriging
- Nearest Neighbor analysis
Correct answer: Kernel Density Estimation (KDE)
Kernel Density Estimation is the standard method for estimating home range utilization distributions from GPS or acoustic telemetry point data.
Question 5: A fisheries GIS dataset uses WGS84 as its datum. What does this primarily define?
- The map scale and resolution
- The reference ellipsoid and origin for coordinate measurements (Correct answer)
- The color scheme for thematic mapping
- The file format for spatial data storage
Correct answer: The reference ellipsoid and origin for coordinate measurements
WGS84 (World Geodetic System 1984) defines the reference ellipsoid, origin, and orientation used to describe positions on the Earth's surface.
Question 6: Which GIS network analysis function would best help identify the fastest boat route to access remote sampling stations on a river system?
- Shortest path (least-cost) routing (Correct answer)
- Watershed delineation
- Interpolation
- Buffer analysis
Correct answer: Shortest path (least-cost) routing
Shortest path or least-cost routing through a network dataset finds the optimal route between points based on travel time or distance impedance.
Question 7: What GIS metadata element is most critical to document when sharing a fisheries spatial dataset with other agencies?
- The map legend color choices
- Coordinate reference system, data source, and collection date (Correct answer)
- The GIS software version used
- The file size of the dataset
Correct answer: Coordinate reference system, data source, and collection date
Coordinate reference system, provenance, and date are essential metadata so other users can correctly project, interpret, and assess the currency of the dataset.
CFP Geographic Information Systems 3
A fisheries manager is combining a benthic substrate layer with a water depth layer to identify spawning habitat.
What GIS operation is being used?