A brief introduction to the concept of LiDAR imagery.

1. Josiah Parry April 12, 2016
Intro to LiDAR?
What is LIDAR?
LiDAR (Light Detection and Ranging) is
a remote sensing method that creates
images from an optical laser system.
LiDAR is most commonly used on
planes and helicopters.
LiDAR works on the same principals
as sonar. It emits laser pulses and
returns to the light sensor whenever it
encounters a surface. A return records
geospatial information. LiDAR can have
multiple returns for each laser; the ?irst
return is always the most important.
There are generally as many returns as re?lective
surfaces in a path. Following this principle, the ?irst
return is generally vegetation, and the last return
contains—most of the time—bare-earth terrain
models. These returns generate information that can
be used to create three-dimensional point data. Unlike
most imaging techniques where information can only
be understood as latitude an longitude coordinates,
we can obtain elevation from our returns. LiDAR
records the elevation at which the return was sent,
and this is where our third (Z) coordinate originates.
For each point that is collected a measure of
intensity is taken. Intensity is a measure based partly
on the re?lectivity of the object encountered during the
return. Intensity can be used to create grayscale imagery.
Remote Sensing Application 1