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Airborne LIDAR Topographic Surveying


Quiz Questions

1._________________ is an active sensory system that uses light, laser light, to measure distances.
LIDAR
Remote sensing
2. LIDAR mapping technology is capable of collecting elevation data with an accuracy of 15 cm and horizontal accuracies within 1/1000th of the flight height.

True
False
3.In order to achieve accuracies, LIDAR systems do not rely on the Global Positioning System (GPS) and an inertial reference system (IRS).
True
False
4.An interfaced _______________________________ records the pitch, roll, and heading of the platform.
Intensive Measurement Unit (IMU)
Inertial Measurement Unit (IMU)
5.A kinematic airborne GPS system locks on to at least four navigation satellites and registers the spatial position of the aircraft.
True
False
6.Figure 11-2 illustrates a _______________________________.
LIDAR sensor in aircraft
Generalized schematic of a LIDAR system
7.Corridor mapping is not an application of a LIDAR system.
True
False
8.The New Orleans District has used LIDAR to map sections of levee along the Mississippi River allowing them to create cross sections and identify floodwall structures near the levees and areas on the levee needing repair. They have also used the same system for planning of levee construction projects.
True
False
9.Data collection from a LIDAR system cannot be used to plan and monitor areas for depositing dredge material.
True
False
10.The Federal Emergency Management Agency (FEMA) is not a partner with the state of North Carolina for the first statewide floodplain mapping project.
True
False
11.The ____________________________ measures the LIDAR system orientation in roll, pitch, and heading.
GPS (Global Positioning System)
IMU (Inertial Measurement Unit)
12.The control stations must be within 30 to 40 km of the project area. In some cases, the base station is set adjacent to the aircraft at takeoff and landing.
True
False
13.Successful processing of LIDAR data normally does not requires both system calibration and quality control data collection.
True
False
14.A cross flight line is a line that is ____________________________ to and intersects the job flight lines.
Parallel
Perpendicular
15.The primary function of the cross flight is to detect systematic errors such as a false increase in elevation of data away from nadir or line to line, detection of anomalies in individual lines, and to demonstrate the repeatability of results.
True
False
16.To provide the maximum information content, the cross lines should not intersect the primary job lines in clear open areas with no vegetation.
True
False
17.Figure 11-4 illustrates _____________________________.
Airport calibration control scheme
First and last return sensors
18.Since positioning of the LIDAR sensor will be performed relative to the ground control stations used, proper setup and configuration of the GPS antennas and receivers is very important.
True
False
19.Once the system is configured and f light lines are established, the operator does not need to monitor the progress of the data collections to ensure data are being received back to the sensor.
True
False
20.During data processing, a quality control review must examine the data for anomalies, systematic errors, or any potential horizontal or vertical bias.
True
False
21.Figure 11-6 illustrates ___________________________.
DGPS processed trajectory of aircraft
Raw LIDAR data
22.Surface model generation is not accomplished by assigning colors or shades of gray to reflectance intensity from the sensor pulses.
True
False
23.If one control point is closer to the project site than the other, then it is expected that there will be slight differences in the two DGPS trajectory solutions.
True
False
24.GPS data collected on a moving platform such as an all terrain vehicle or car across the collection area, can be post processed and used for comparison to the LIDAR X,Y, Z data.
True
False
25.____________________data collection can offer scheduling and cost advantages over labor-intensive air photo mapping because it offers rapid data collection and fast post processing.
GPS

LIDAR