In August 2005, Hurricane Katrina devastated the Gulf Coast of the United States, leaving in its wake an unprecedented loss of life and property damage. Among the critical infrastructure the storm affected was the levee system that controls the Mississippi River’s flow around the city of New Orleans.

During the aftermath of this most destructive storm, a surveying firm was approached by a client seeking a survey of the existing levee system to be carried out with an accuracy standard of 3 to 5 cm. First they sought airborne light detection and ranging (LIDAR) data (i.e., surveying the levees from an aircraft flying overhead using an airborne laser scanner), correctly assuming this would be the fastest way to gather accurate topographic position data.

The survey firm informed the client of another option, mobile LIDAR mapping. Like airborne mapping, terrestrial mobile mapping exploits the same technology, but instead of the LIDAR equipment being installed in an aircraft, it is mounted on a ground survey vehicle such as a car, van, or truck. Assured that terrestrial mobile mapping would be just as cost-effective as airborne mapping, they decided to test this method. Monitoring through LIDAR technology helps engineers assess the current state of the levee systems. A number of indicators can be checked, such as subsidence monitoring around flood walls. Change-detection in the physical levees is another vital application.

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