Technology & Digital Tools Flashcards

What does 'georeferencing' a scanned historical map or aerial photo accomplish in a GIS workflow?

Answer: It assigns real-world geographic coordinates to the image so it aligns with other spatial data

Georeferencing assigns control points linking pixel locations to known geographic coordinates, enabling spatial alignment with other GIS layers.

Which component of a GPS receiver is responsible for differentiating signals from multiple satellites to improve positional accuracy?

Answer: The internal clock maintaining precise timing for signal travel-time calculations

GPS positioning relies on precise timing of signal travel from satellites; the receiver's internal clock enables accurate distance calculations to each satellite.

A forester wants to estimate above-ground biomass across a 10,000-acre watershed. Which remote sensing approach provides the most efficient landscape-scale estimate?

Answer: Airborne LiDAR-derived canopy height models combined with allometric equations

Airborne LiDAR canopy height models cover entire landscapes and, when combined with allometric equations, provide statistically robust biomass estimates.

In GIS topology, what does a 'sliver polygon' represent and why is it problematic for forest stand maps?

Answer: A tiny erroneous polygon created at the boundary of two overlapping layers due to minor digitizing mismatches

Sliver polygons are artifacts from slight boundary mismatches between overlaid layers and can create false stand entries with invalid attributes.

Which USFS national program provides standardized, plot-based forest inventory data at a state and national scale, and integrates with digital databases accessible to foresters?

Answer: FIA (Forest Inventory and Analysis)

The USFS Forest Inventory and Analysis (FIA) program conducts annual plot-based inventories and provides public database access for analysis.

What is the main difference between supervised and unsupervised classification in remote sensing image analysis?

Answer: Supervised classification uses field-validated training samples to define classes; unsupervised classification groups pixels by spectral similarity without predefined classes

Supervised classification requires analyst-defined training areas for each class; unsupervised clustering algorithms group spectrally similar pixels without prior class definitions.

A forester needs to share stand-level GIS data with a state agency using a different GIS platform. Which open, interoperable format is the best choice for broad compatibility?

Answer: GeoPackage (.gpkg) or GeoJSON

GeoPackage is an OGC open standard supported by virtually all GIS platforms, and GeoJSON is universally readable — both avoid proprietary format lock-in.