LiDAR Explained Simply: What Is It and How Does It Work Using LiDAR Drone Mapping?

LiDAR stands for Light Detection and Ranging. The simplest way we explain it is that LiDAR uses laser light to measure the world around us, using LiDAR drone mapping.

Our LiDAR unit is a DJI Zenmuse L2. While the drone is flying, the L2 is sending out laser pulses and measuring the time it takes for that light to hit something and return to the sensor. From those measurements, we can determine where objects and surfaces are in three-dimensional space.

And it's doing this incredibly fast. The L2 has a laser pulse emission frequency of 240,000 pulses per second. In multiple-return mode, it can produce as many as 1.2 million points per second, with up to five returns from a single laser pulse.

The easiest way to understand those returns is to picture us flying over a wooded property.

A regular aerial camera looking down is primarily going to photograph the tree canopy. That's useful if you want to see what the property looks like from above, but it doesn't necessarily tell you what's happening on the ground underneath those trees.

LiDAR is different.

A laser pulse may encounter the top of the vegetation, while other laser energy can travel through openings in the leaves and branches and reach surfaces farther below. Because the L2 can record multiple returns, we can collect information from different levels of that vegetation and, importantly, collect points from the ground beneath it.

That's why you'll sometimes hear people say that LiDAR can see things the human eye can't see.

It doesn't literally see through solid trees or objects. Instead, the laser pulses can find openings between leaves, branches and vegetation and reach the ground below. During processing, we can separate much of that vegetation from the ground data.

Once you essentially take those trees and brush out of the picture, you can get a much clearer look at the actual terrain underneath.

And that's where LiDAR gets really interesting.

Suddenly, we may be able to see the actual shape of the land—the slopes, depressions, ditches, drainage areas, embankments, old roads or other terrain features that were very difficult to recognize when you were simply looking at a wooded property.

The end result is what's called a point cloud. Think of it as millions of individual measured points that, when put together, create a highly detailed three-dimensional representation of the area we flew.

So when somebody asks us the difference between taking drone photographs and collecting LiDAR, we usually put it this way:

A camera is excellent at showing you what something looks like. LiDAR helps us understand the shape and structure of what's actually there—including terrain that may be hidden beneath vegetation.

And that's also why we don't automatically recommend LiDAR for every project. It's a powerful tool, but the first question should always be:

What are you trying to find out?

Once we know that, we can determine whether LiDAR is actually the right tool for the job.