Geographic Information Systems Flashcards

In precision agriculture, what does the term 'variable rate technology' (VRT) refer to?

Answer: Adjusting input application rates spatially across a field based on GIS prescription maps

VRT uses GPS and GIS prescription maps to automatically adjust seed, fertilizer, or pesticide application rates as equipment moves through different field zones.

What type of GIS analysis would a farmer use to determine the flow path of surface water across a field after a heavy rain event?

Answer: Watershed and flow direction analysis using a DEM

Flow direction analysis derived from a DEM calculates the path water takes downslope, identifying drainage channels and low-lying areas prone to pooling.

Which file format is most commonly associated with storing vector GIS data in a widely compatible format?

Answer: .shp (Shapefile)

The Shapefile (.shp, with associated .dbf, .shx files) is one of the most universally supported vector GIS formats, readable by nearly all GIS software.

A GAP auditor reviews a grower's GIS records and notes that field maps lack a north arrow and scale bar. Why is this a concern?

Answer: Without orientation and scale, maps cannot be accurately interpreted or used for distance and area measurements

A north arrow and scale bar are essential cartographic elements that allow map users to determine direction and measure real-world distances, making the map interpretable.

What is the main purpose of georeferencing a scanned paper farm map in GIS?

Answer: To align the scanned image to real-world coordinates so it can be used with other spatial data

Georeferencing assigns spatial coordinates to a raster image, allowing it to be overlaid and analyzed alongside other geo-referenced data layers.

Which GIS interpolation method is commonly used to create a continuous soil nutrient surface map from point sample data?

Answer: Kriging or IDW (Inverse Distance Weighting)

Kriging and IDW interpolate values at unsampled locations based on measured sample points, producing a smooth surface map of nutrient levels across a field.

Under GAP traceability requirements, a GIS field ID linked to harvest records allows a produce buyer to do which of the following?

Answer: Trace a product lot back to the specific field where it was grown

Linking a unique field ID from GIS to harvest and shipping records enables traceback to the exact growing location, a core requirement of produce traceability programs.