Geographic Information Systems Flashcards
7 cards from real CEP 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 federal agency maintains the National Hydrography Dataset (NHD) used extensively in environmental GIS applications?
Answer: USGS
The U.S. Geological Survey (USGS) maintains the National Hydrography Dataset, which maps streams, rivers, lakes, and other water bodies across the United States.
In GIS, what does the term 'attribute join' accomplish?
Answer: Links non-spatial tabular data to spatial features using a common field
An attribute join links a table of non-spatial data to a spatial layer by matching records through a common field, such as joining census data to census tract boundaries.
What type of error occurs in GIS when digitized boundaries between adjacent polygons do not perfectly align, creating spurious thin slivers?
Answer: Sliver polygon error
Sliver polygons are thin, erroneous artifacts created when boundaries from two datasets don't perfectly align, often resulting from digitizing the same boundary from different sources.
Which GIS analysis would best help an environmental planner delineate wetland buffers required under state regulations?
Answer: Buffer and intersect operations
Buffer operations create zones at specified distances from wetland boundaries, and intersecting those zones with parcel data identifies regulated areas requiring permits.
What distinguishes LiDAR data from traditional aerial photography in GIS applications?
Answer: LiDAR provides three-dimensional point cloud data enabling detailed terrain and structure modeling
LiDAR uses laser pulses to measure precise distances and creates dense three-dimensional point clouds that can distinguish ground surface, vegetation structure, and built features.
In GIS metadata, what does 'positional accuracy' describe?
Answer: How closely the recorded location of a feature matches its true location on Earth
Positional accuracy describes the degree to which the geographic coordinates stored in a dataset correspond to the actual location of features on the ground.
Which type of GIS analysis is used to identify statistically significant clusters of high or low values across a study area?
Answer: Hot spot analysis (Getis-Ord Gi*)
Hot spot analysis using the Getis-Ord Gi* statistic identifies statistically significant spatial clusters of high values (hot spots) and low values (cold spots).