CET FINAL EXAM
The use of technology has improved throughout the years. The instruments now have faster processing, more accurate readings, and lighter and more compact. This paper will investigate how these technologies are being use for the assessment of the damages of Super Storm Sandy. Two equipment instruments, LIDAR and Ground Penetrative Radar (GPR) will be covered in the assessment. The following questions will be answered with respect to said equipment:
1. Reestablishment of the limits of the shore line
2. Location of streets and foundations of houses destroyed/moved by the storm
3. Analysis of buildings moved/damaged by the storm in determining whether a building is structural sufficient or needs to be demolished.
4. Safety of the boardwalk and its infrastructure.
a. Structural integrity of the boardwalk, its foundation and the associated structures located on and along the Boardwalk.
b. The safety and condition of the infrastructure that supports the Boardwalk and its features with respect to the fire that occurred after last summer that destroyed the rebuilt Boardwalk.
LIDAR (Light Detection and Ranging) is a remote sensing method that uses light in the form of a pulsed laser to measure distances to the Earth. These light pulses – combined with other data recorded by the airborne system – generate precise, three-dimensional information about the shape the Earth and its surface characteristics. There are two types of LIDAR, topographic, and bathymetric. Topographic LIDAR uses a near-infrared laser to map the land while bathymetric LIDAR uses water-penetrating green light to measure seafloor and riverbed elevation. LIDAR can be used to map the limits of the reestablished shore line by having the ability to collect data from the air. The sensor used in this method, combines the measurements that were collected with position and orientation data generated from an integrated GPS and Inertial Measurement Unit systems, scan angles, and calibration data. These groups of elevation points create a point cloud. Each point has the following information: latitude, longitude, and height that represent a particular point on the Earth surface thus creating contours and models of the land (National Ocean Service).
This method can be very useful when one is required to estimate the change of the position of the shoreline due to Super Storm Sandy. In Estimation of Shoreline Position and Change using Airborne Topographic Lidar Data, authors Hilary F. Stockdon, Asbury H. Sallenger, Jr., Jeffery H. List and Rob A. Holman investigated the change of the shoreline of the Outer Banks of North Carolina for the Journal of Coastal Research. They were able to conclude that their estimate fell within a root mean square difference of 2.9 meters when compared to measurement obtained by a ground based GPS vehicle survey system. A mean 95% confidence interval for shoreline position was plus or minus 1.4 meters. This technique displays a high accuracy reading...