GPS and Field Data Collection Flashcards
6 cards from real GISP practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 GPS and Field Data Collection flashcards as text
What quality control step is essential after importing field-collected GPS data into a GIS to verify positional accuracy?
Answer: Comparing collected features against high-accuracy reference data or orthoimage backdrops
Overlaying field-collected GPS data against accurate reference imagery or orthophotos allows visual and statistical assessment of positional accuracy before the data is incorporated into production datasets.
GNSS (Global Navigation Satellite System) is a broader term that encompasses which constellation systems beyond the US GPS system?
Answer: GPS (US), GLONASS (Russia), Galileo (EU), and BeiDou (China)
GNSS is the generic term for all satellite navigation constellations worldwide, including the US GPS, Russia's GLONASS, the European Union's Galileo, and China's BeiDou (Compass) systems.
During GPS post-processing, what is the purpose of applying an antenna phase center correction?
Answer: To account for the offset between the physical antenna mount point and the true signal measurement point
The antenna phase center is not at the physical top of the antenna but at a frequency-dependent offset point; applying phase center corrections ensures that measurements reference the true geometric center of signal reception.
In a field data collection plan for a large-area utility inventory, which data model best supports collecting lines, points, and related attributes with topological relationships enforced?
Answer: Geodatabase feature dataset with a geometric network or utility network
A geodatabase feature dataset with a geometric or utility network enforces topology, connectivity, and attribute domains, making it the appropriate model for utility inventory data requiring relational integrity.
What is the recommended minimum mask angle (satellite elevation cutoff) used in most GPS survey configurations to reduce atmospheric error and multipath?
Answer: 15 degrees
A 15-degree elevation mask is commonly used to exclude low-elevation satellites whose signals travel a longer atmospheric path, increasing ionospheric and tropospheric delays and multipath susceptibility.
When using a total station in conjunction with a GIS field workflow, what is the key advantage over GPS-only data collection in forested or urban canyon environments?
Answer: Total stations use line-of-sight angle and distance measurements independent of satellite signals
Total stations measure horizontal angles, vertical angles, and slope distances using optical line-of-sight, allowing precise surveying in environments where satellite signal reception is blocked or degraded.