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Light Detection and Ranging (LiDAR)

   

   EarthExplorer browse images are
   displayed as a 2-dimensional color
   shaded representation of point
   cloud data as shown by this coverage
   over Lake County, Illinois (2007).

LIDAR (Light Detection and Ranging) is a remote sensing technology that collects 3-dimensional point clouds of the Earth’s surface. This technology is being used for a wide range of applications including high-resolution topographic mapping and 3-dimensional surface modeling as well as infrastructure and biomass studies. Airborne LIDAR instrumentation uses a laser scanner with up to 400,000 pulses of light per second. The laser transmits pulses and records the time delay between a light pulse transmission and reception to calculate elevation values. These values are integrated with information from the aircraft’s Global Positioning System (GPS) and orientation (pitch, roll, and yaw) data from inertial measurement technology to produce point cloud data. Each data point is recorded with precise horizontal position, vertical elevation, and other attribute values. 

Point cloud data represent the elevation of landscape features including crops, forests, roads, railways, airports, bare earth, mountains, valleys, lakes, rivers, glaciers, buildings, and other urban development. Topographic LIDAR instruments use wavelengths in the near-infrared regions of the spectrum with a Nominal Pulse Spacing (NPS) of 3 meters or finer. Since LIDAR can be reflected from any object the laser pulse strikes, up to five returns are collected per pulse. The multiple returns are recorded and each point is assigned a classification to identify landscape features.
The intensity of the reflected energy is also captured and can be analyzed to
provide additional information on terrain characteristics.

LiDAR Products

LIDAR discrete-return point cloud data are available through EarthExplorer in the American Society for Photogrammetry and Remote Sensing (ASPRS) LAS format. The LAS format is a standardized binary format for storing 3-dimensional point cloud data and point attributes along with header information and variable length records specific to the data. Millions of data points are stored as a 3-dimensional data cloud as a series of x (longitude), y (latitude), and z (elevation) points.

The LIDAR collection has been acquired by the USGS through contracts, through partnerships with other Federal, state, tribal, or regional agencies, from direct purchases from private industry vendors, and through volunteer contributions from the science community. Product specifications such as nominal pulse spacing, area of coverage (footprint), file size, and projection will vary by project since the data come from a variety of sources. The USGS EROS Center manages and distributes LIDAR point cloud data dating back to 2000 for projects from across the United States.    

Data Limitations: LIDAR data products presented through EarthExplorer are considered public information and may be distributed or copied. While the USGS makes every effort to provide accurate and complete information, the USGS provides no warranty, expressed or implied, as to the accuracy, reliability, or completeness of furnished LIDAR point cloud data. Please note that the USGS does not control and cannot guarantee the relevance, timeliness, or accuracy of these outside materials.

Additional Information:

Data Use and Citation Policies

For information on how to cite USGS data plus guidance on usage restrictions,
please see our Data Citations and Use page at https://lta.cr.usgs.gov/citation.

Contact Information for User Assistance

Long Term Archive User Services
U.S. Geological Survey (USGS)
Earth Resources Observation and Science (EROS) Center
47914 252nd Street
Sioux Falls, SD 57198-0001

Phone Number: 605-594-6151
Toll Free: 800-252-4547
Fax: 605-594-6589

Email:lta@usgs.gov
Web: https://lta.cr.usgs.gov

Business Hours: Monday thru Friday, 8:00 a.m. to 4:00 p.m., Central Time