Geographic Information Systems Flashcards
7 cards from real SAF practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Geographic Information Systems flashcards as text
Which map projection is most commonly used for large-scale forestry operations in the contiguous United States?
Answer: Albers Equal-Area Conic
Albers Equal-Area Conic preserves area relationships, making it ideal for measuring forest extent across the contiguous US.
In a GIS forest inventory, what does a 'topology rule' primarily enforce?
Answer: Spatial relationships between features such as no gaps or overlaps
Topology rules enforce spatial integrity by ensuring features relate correctly, such as stand polygons having no gaps or overlaps.
A forester needs to identify all stands within 300 meters of a perennial stream. Which GIS operation is most appropriate?
Answer: Buffer
A buffer operation creates a zone of specified distance around a feature, in this case 300 m around stream lines.
What is the primary advantage of using a geodatabase over a shapefile for managing a large forest inventory?
Answer: Support for topological rules, domains, and relationship classes
Geodatabases support topological rules, attribute domains, subtypes, and relationship classes that shapefiles cannot enforce.
When performing a spatial join in a forestry GIS, what is the key distinction between 'one-to-one' and 'one-to-many' join types?
Answer: One-to-many retains all matching records while one-to-one keeps only the first match
A one-to-many join retains all matching records from the join layer, while a one-to-one join keeps only the first (or summarized) match per target feature.
Which remote sensing index is most commonly used to detect forest stress and declining canopy health?
Answer: NDVI (Normalized Difference Vegetation Index)
NDVI uses near-infrared and red bands to quantify vegetation greenness, making it the standard index for monitoring canopy health.
In LiDAR-derived data used for forestry, what does 'point cloud density' (points per square meter) primarily affect?
Answer: The accuracy of canopy height models and tree detection
Higher point cloud density allows finer resolution canopy height models and improves individual tree detection accuracy.