The Colorado Geological Survey is actively involved in the acquisition of LiDAR data within Colorado. We are cooperating with other State and Federal agencies with the ultimate goal of completing a LiDAR survey of the entire state. Please read below for more information on the uses and benefits of LiDAR.
CGS LiDAR of the San Luis Valley
What is LiDAR?
LiDAR stands for "light detection and ranging." The state-of-the art technology utilizes the projection of millions of laser signals to the ground from a specially equipped aircraft. The result is extremely detailed ground elevation data for areas of Colorado. The data from these LiDAR reflections are collected by measuring the time it takes for the aircraft to receive each of the millions of laser reflections. The resulting data is then combined and converted into an elevation image that looks exactly like the terrain below the aircraft, including buildings, trees, roadways, creeks, and rock outcrops. Also, using powerful software the "raw" lidar data can be processed to generate a number of useful end products, including an accurate "bare-earth" terrain model in which trees, vegetation, and manmade structures have been edited out.
How does it work?
LiDAR systems vary by manufacturer, but all use the following instrumentation: a laser source and detector; a scanning mechanism and controller; airborne GPS and IMU equipment; a high-accuracy, high-resolution clock for timing laser emissions, reflections, GPS/IMU, and scan-angle measurements; high performance computers; and high capacity data recorders. With these components, lidar data collection is possible:
How is the data used?
- A pulse of laser light is emitted and the precise time is recorded
- The reflection of that pulse from the surface is detected and the precise time is recorded
- Using the constant speed of light, the time difference between the emission and the reflection can be converted into a slant range distance (line-of-sight distance)
- With the very accurate position and orientation of the sensor provided by the airborne GPS and inertial measurement unit (IMU) data, the XYZ coordinate of the reflective surface can be calculated
Lidar offers many advantages over traditional photogrammetric methods for collecting elevation data. These include high vertical accuracy, fast data collection and processing, robust data sets with many possible products, and the ability to collect data in a wide range of conditions.
Because of LiDAR's ability to "see" through vegetation, the CGS will use the data to map unknown young faults, more accurately locate previously mapped faults, and determine the potential for geothermal energy in these faulted areas. The data will also be used for creating highly detailed maps of other geologic hazards, such as landslides, rockfall, and areas prone to flooding.
USGS - LIDAR Viewer
Colorado Geological Survey