USGS - science for a changing world

Data Series 921

Ground-Based Lidar Beach Topography of Fire Island, New York, April 2013

Skip Links

Project Summary
Survey Overview and Acquisition
Data Processing
References Cited


The high-resolution lidar data of the coastal zone at Fire Island, N.Y., were collected by the USACE-FRF team and are only one component of a larger dataset collected using the CLARIS platform. CLARIS is a vehicle-mounted system that integrates a terrestrial lidar scanner and X-band radar with precise motion and position information. For further information or questions regarding the CLARIS or for additional data not included in this report, please contact the USACE-FRF.

Riegl VZ-1000

Surface elevation data were captured using the Riegl VZ-1000 terrestrial laser scanner mounted on a 4x4 vehicle. This is the key piece of equipment used in this type of data acquisition. The terrestrial scanner images the topography by emitting a rapid series of infrared laser pulses across the beach and continuously measuring surface contact distance. Together with accurate scanner positional data, these measurements are used to create a 3-dimensional (3-D) point cloud of the surface.

POS-LV 220

Position data during the lidar scan were recorded using the Applanix POS-LV 220, a fully integrated system composed of an L1/L2 phase global positioning system (GPS) receiver, an inertial measurement unit (IMU), and a distance measuring instrument (DMI).

The GPS data were collected through the two global navigation satellite system (GNSS) Zephyr* antennas and internal GPS receivers. The 3-D motion of the vehicle (yaw, pitch, roll) was recorded by the IMU, and the DMI measured the vehicle wheel rotations. All information from these sensors were then merged during post-processing to maintain sub-decimeter positional accuracy. Additionally, prior to beginning the survey the laser scanner was bore-sighted with respect to the IMU to account for subtle mounting differences between the two sensors, a process which can reduce data measurement error.

Various CLARIS instruments mounted atop the mobile CLARIS unit
Figure 4. Various CLARIS instruments mounted atop the mobile CLARIS unit including 2 GNSS Zephyr antennas (outer masts), Riegl laser scanner (right of center), and marine radar antenna (top center). [larger version]

*Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

Accessibility FOIA Privacy Policies and Notices logo U.S. Department of the Interior | U.S. Geological Survey
Page Contact Information: Contact USGS
Page Last Modified: Monday, November 28, 2016, 08:32:00 PM