Training to Use New Lidar (Light Detection and Ranging) Scanner in Santa Cruz, California

By Helen Gibbons Jan. / Feb. 2013

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A newly acquired terrestrial lidar (light detection and ranging) scanner was the focus of training at the U.S. Geological Survey (USGS) Pacific Coastal and Marine Science Center in Santa Cruz, California, in December 2012. USGS technicians and scientists learned how to operate the new instrument during a 4-day workshop organized by Deputy Center Director for Marine Operations George Tate and geographer Joshua Logan.

Above: (Left to right) USGS geologist Amy Draut, Riegl USA instructor Bret Bienkowski, USGS geographer Josh Logan, and USGS physical scientist Jackson Currie observe data collected by the new lidar scanner (to left of group) at Younger Lagoon in Santa Cruz, California. Photograph by Tom Reiss, USGS. [larger version]

Lidar scanners use laser light to measure distances, producing highly accurate three-dimensional maps and images of terrain. USGS scientists make extensive use of lidar to study landscape change, employing both airborne lidar scanners (for example, see lidar maps of coastal change caused by Hurricane Sandy) and ground-based lidar scanners (read about ground-based lidar to track rapid coastal change in USGS Fact Sheet 2006–3111; see Virtual Fly-Through Along the Lower Elwha River for an example of ground-based lidar used to document the shape of the Elwha River, Washington, before removal of two large dams).

The newly acquired scanner—a RIEGL VZ-1000—is a ground-based unit that can be mounted on a tripod for surveying coastal terrain from positions on land or mounted on a moving platform, such as a boat or car, for conducting surveys while underway.

Riegl USA representative Bret Bienkowski taught the December workshop, beginning with an introduction to the lidar scanner and its software. On the second day of the training, participants took the instrument into the field, scanning terrain at Younger Lagoon, about 1 mile southwest of the Pacific Coastal and Marine Science Center, for comparison with data from previous surveys. The rest of the workshop focused on post-processing, data flow, and data management.

Above: Scan by the new lidar scanner at Younger Lagoon in Santa Cruz, California, on December 11, 2012. Shaded swath from left of center to lower right corresponds to swath of yellow data in image below. True colors (tans, greens, and so on) are created by combining lidar data with imagery from a high-resolution digital camera attached to the scanner. Image courtesy of Josh Logan, USGS. [larger version]

Above: Lidar data collected December 11, 2012 (yellow), in comparison with lidar data collected October 29, 2010 (red), showing change in beach profile. Spot marked by vertical arrow was 1.08 meters higher at time of 2012 survey than at time of 2010 survey. Such measurements are possible because the points in each lidar data set have precise x, y, and z coordinates. Image courtesy of Josh Logan, USGS. [larger version]

The addition of the scanner to the Pacific Coastal and Marine Science Center instrument pool will complement existing lidar capabilities. The instrument will not only save the center considerable equipment-rental expenses in future work but also provide additional capabilities important to center scientists, such as:

• The ability to scan from a moving vessel, allowing center personnel to conduct topographic surveys concurrently with bathymetric surveys and thus collect co-registered elevation data from coastal land and adjacent seafloor. (Read about such mapping tested by the USGS in the Gulf of Mexico in July 2011, USGS Scientists Develop System for Simultaneous Measurements of Topography and Bathymetry in Coastal Environments.)
• The ability to detect and record "multiple returns" for each laser pulse emitted. When the laser light reflects off multiple objects (for example, several pieces of vegetation and the ground behind it), the scanner can record the location of each object. Processing software can distinguish between these multiple returns, which can assist in filtering out vegetation data from ground-surface data.
• The ability to collect geographically registered data sets by using a Geographic Positioning System (GPS) interface, a built-in electronic compass, and an inclinometer.

The first scientific use of the new lidar scanner will likely be continued surveying along the Elwha River to document the changes caused by dam removal. Stay tuned!

New Video Shows a Virtual Fly-Through Along the Lower Elwha River, Washington, Using Recently Acquired Ground-Based Lidar Data Mar. / Apr. 2012

USGS Scientists Develop System for Simultaneous Measurements of Topography and Bathymetry in Coastal Environments Sept. / Oct. 2011

Coastal Change Hazards: Hurricanes and Extreme Storms USGS

Land-Based Lidar Mapping—a New Surveying Technique to Shed Light on Rapid Topographic Change USGS

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Jan. / Feb. 2013

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in this issue:

cover story:
Water-Quality Dynamics in Barnegat Bay-Little Egg Harbor Estuary

Hurricane Sandy Disrupts Estuary Study, Provides Additional Research Opportunities

USGS Scientists Collaborate in Coastal Groundwater Study

Tracking Pacific Walrus: Expedition to the Shrinking Chukchi Sea Ice

USGS Contributes to Success of St. Petersburg Science Festival

South Korean Geoscientists Visit the USGS in California

Strategic IODP Planning Workshop for Ultra-Deep Drilling into Arc Crust

Training to Use New Lidar Scanner

Remembering Asbury "Abby" Sallenger

Research Vessel Named for Retired USGS Scientist

A Passion for Educational Outreach—Profile of Carol Reiss

Jan. / Feb. 2013 Publications