GIS - Geographic Information System Geospatial Data Acquisition Questions and Answers

Question 1

A key distinction between active and passive remote sensing systems is their source of energy. Which of the following data acquisition technologies is considered an active remote sensing system?

Accepted Answer

LiDAR (Light Detection and Ranging)

Answer

Landsat 9 OLI/TIRS

Answer

MODIS (Moderate Resolution Imaging Spectroradiometer)

Answer

Aerial photography with a standard digital camera

Question 2

A GIS analyst is working with a raw aerial image of a mountainous region. When overlaying vector road data, the analyst notices significant misalignment, with roads appearing displaced from their true ground positions, especially in areas of high relief. What process is required to correct these geometric distortions caused by terrain variation and sensor tilt?

Accepted Answer

Orthorectification

Answer

Georeferencing

Answer

Rasterization

Answer

Spatial interpolation

Question 3

A survey team needs to capture highly accurate elevation data for a small, densely vegetated watershed to support a detailed hydrological modeling project. They require a method that can penetrate the forest canopy to map the bare earth terrain beneath. Which of the following acquisition methods would be most suitable for this task?

Accepted Answer

Airborne LiDAR survey

Answer

Structure from Motion (SfM) photogrammetry

Answer

Collecting points with a standard consumer-grade GPS unit

Answer

Digitizing contour lines from an existing topographic map

Question 4

An unmanned aerial vehicle (UAV) is used to conduct a survey for a new construction project. To achieve centimeter-level accuracy without requiring a constant, real-time data link between the UAV and a base station, the surveyor records raw GNSS data on both the UAV and a stationary base. The data is corrected after the flight. What is this GNSS data collection technique called?

Accepted Answer

Post-Processed Kinematic (PPK)

Answer

Differential GPS (DGPS)

Answer

Autonomous GNSS

Answer

Real-Time Kinematic (RTK)

Question 5

Which of the following is a primary data source for creating a global Digital Elevation Model (DEM) with near-global coverage, famously collected during a Space Shuttle mission in 2000?

Accepted Answer

Shuttle Radar Topography Mission (SRTM)

Answer

The National Map (TNM)

Answer

Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER)

Answer

Geostationary Operational Environmental Satellite (GOES)

Question 6

Structure from Motion (SfM) is a photogrammetric technique used to create 3D models and point clouds from overlapping 2D images. Which of the following is a critical requirement for a successful SfM data acquisition?

Accepted Answer

Capturing a series of images with significant overlap from multiple perspectives.

Answer

Using a camera with an integrated laser scanner.

Answer

Ensuring all photographs are taken from the exact same location.

Answer

Taking all photos at precisely the same time of day to ensure consistent lighting.