Light Detection and Ranging elevation data (Lidar) is an optical remote sensing technology that can measure the distance to, or other properties of a target by illuminating the target with light pulses from a laser and measuring the time and intensity of the pulse return to the sensor. Laser pulses from the sensor can exceed 150,000 pulses per second. Aircraft position (X,Y,Z) is measured twice a second while aircraft attitude (pitch, roll, yaw) is measured 200 times per second. Currently this is the most accurate type of elevation data available. There are two main types of Lidar collections, Terrestrial and Airborne. Airborne Lidar is most commonly used and available from UGRC.

Lidar point clouds can be classified so that each point in the cloud is designated a land cover type (ex. ground, water, road, building, vegetation, etc.) in addition to an elevation value. The vendor for the 2013-2014 Wasatch Front Lidar project, Watershed Sciences Inc. (WSI) now a Quantum Spatial company, has provided the samples below that show some of what can be done with the collected Lidar data. Please note that while the sample data below contains LAS point cloud data that are fully classified, the point clouds delivered for most projects only have the following classifications (including intensity & return number), yet further classification of the point cloud is possible.

Standard Classification Codes

Code 1

Processed, but unclassified

Code 2

Bare-earth ground

Code 7

Noise

Code 9

Water

Code 10

Ignored Ground (Breakline proximity)

Code 11

Withheld