A Complete Guide To What Is Lidar: Light Detection And Ranging

Ever imagined that you can calculate how far everything is away from you? Yes, LiDAR (Light Detection and Ranging) does this for you. Excited to know what is LiDAR? What are its types and what magic it can perform in this era of modern technology? Let’s have a quick look!

What is Lidar (Light Detection and Ranging)?

Basically, LiDAR is a distance technology. It is the latest disruptive technology having its use in various fields and now in the construction industry as well. From an aircraft or a helicopter, the lidar system actively sends light energy to the ground. The signal hits the ground and returns to the sensor.

It measures the time for the emitted light to return back to the sensor, and in the end, it gets a changeable distance to the Earth.

What are the types of Lidar?

There are basically two types of Lidar: Airborne and Terrestrial Lidar systems.

Let’s take a close look at each type one-by-one.

 

1    1. Airborne Lidar

The Light Detection and Ranging is an exciting technology to know. In the Airborne Lidar, the system installs on the wing of an aircraft or helicopter. The infrared lights are emitted towards the ground, and it returns to the moving airborne lidar sensor. There are two main types of airborne sensors: Topographic and Bathymetric Lidar

2    2. Topographic Lidar

The Topographic Lidar marks its presence to obtain surface models that are useful in many applications such as forestry, urban planning, landscape ecology, coastal engineering as well as survey assessment, etc.

3  3. Bathymetric Lidar

Bathymetric Lidar is a type of airborne lidar that is water penetrating. Many of the bathymetric lidar systems use in collecting elevation and water depth which provides an airborne lidar survey of the land-water interface.

Traditionally, in Bathymetric Lidar systems, the infrared light reflects back to the aircraft from the land and water surface. While the additional green laser travels through the water column and therefore measures the exact distance. To establish water depths and shoreline elevations it uses the analysis of two different pulses. 

The Bathymetric information has its significance near coastlines, in harbors and near shores and boundaries of rivers. The Bathymetric information is also helpful in locating objects on the ocean floor.

Now let’s move on to the next type of Lidar: Terrestrial Lidar

4     4.Terrestrial Lidar

In this Lidar system, there are two main types: Mobile and Static

In the case of mobile, as the name suggests, the lidar system is fixed on a moving vehicle. Whereas, in the case of static, the lidar system is fixed on a tripod or on a stationary device. Both the lidar sensors comprise eye-safe lasers.

The Terrestrial Lidar compiles very dense and highly exact points which allow accurate identification of objects. These compact point clouds are used to manage facilities, conduct highway and railway surveys and even use in creating 3D city models for exterior and interior spaces.

Following is the brief look at Mobile and Static Lidar

5    5.Mobile Lidar

It is the collection of lidar point clouds from a moving base. Mobile Lidar systems include any number of lidar sensors fixed on a moving vehicle. These types of systems mounts on vehicles, trains and even on ships. The Mobile systems consist of a Lidar sensor, cameras, GPS (Global Positioning System), and an INS (Inertial Navigation System) same as like of Airborne Lidar systems.

The Mobile Lidar data is not only useful in analyzing the road infrastructure but also helps in locating the trespassing overhead wires, light poles and various road signs near roadways or rail lines.

6     6. Static Lidar

It is the gathering of lidar point clouds from a static location. Typically, in static lidar, a portable laser-based imaging and ranging sensor are placed on a tripod. These systems collect the lidar point clouds from inside as well as the exterior of the building. The typical application of static lidar systems is engineering, mining, surveying, and archeology.

Lidar Data is precious GIS resource

The Light Detection and ranging, i.e., LiDAR is accurate and covers the large areas on the ground. You can also visualize bare ground elevation, canopy heights, light intensity and much more. Anyone who is looking for understanding landscape topology should, therefore, use LiDAR.

With its tremendous working capabilities, LiDAR is a behemoth of a data set to work with. It uses LAS file format to store the LiDAR files as a point cloud data and hence, streamlines smooth exchange between vendors and customers with no loss of information.

LiDAR Applications

The Light Detection and Ranging make use of lasers to measure the elevation of features like forests, buildings as well as of the plain earth.

It is somewhat similar to sonar (Sound waves) or radar (Radio Waves) as it also sends a pulse and measures the exact time it takes to return. LiDAR is difficult from sonar and radar as it uses light to measure the accurate time as well as distance.

The LiDAR applications are impressive and are undoubtedly growing in GIS systems.

Following are some LiDAR Applications:

Forestry, Archaeology, land use mapping, flood modeling, transportation planning, architecture, oil and gas exploration, public safety, automated vehicles, military, and conservation also make use of Lidar.

We try our best to explain the Light Detection and Ranging. Hope this guide is helpful for you.