LiDAR 101
The Gisica Ltd offers its customer’s a wide variety of image and LiDAR processing services. For those of us who are not very familiar with LiDAR technology, this article aims to give the basic 101 course on LiDAR and its applications. To that end, we have written a simple explanation of what LiDAR is all about. We have also gathered a list of different fields that use LiDAR technology and provide short examples how they profit from it.
WHAT IS LiDAR?
LiDAR is a method that is used to measure distances with the help of laser light. Originally, the term LiDAR came from the combination of the words light and radar. The target is illuminated with laser light and the time it takes for the laser light reflection to return to the sensor gives us the measurement. The laser return time and wavelengths can be used to give us data to create a 3D representation of the target in question. This can be used further in terrestrial, airborne or even mobile applications.
The first LiDAR prototype was built in 1961 by Hughes Aircraft Company. The company had created its first laser a year earlier. The first application for LiDAR was used in meteorology to measure clouds and pollution. However, it took over 10 years before LiDAR was used in the modern form. Eventually, LiDAR became known. In 1971, during the Apollo 15 mission, astronauts used LiDAR to successfully map the surface of the moon.
As the uses for LiDAR technology have broadened and the technology has evolved, the meaning behind the term “LiDAR” has slightly changed. Nowadays, LiDAR means laser imaging, detection and ranging.
WHAT IS LiDAR USED FOR?
After the successful mapping of the moon’s surface, there have been countless different uses for LiDAR technology. The technology is constantly evolving and new ways of using LiDAR technology are being discovered. Here we have picked a few industry fields that have profited from LiDAR.
MAPPING AND CARTOGRAPH
LiDAR is commonly used to create high-resolution maps. This feature is used in various different fields such as in surveying, geodesy, geomatics, archeology and forestry to mention a few. LiDAR technology provides a great overview and makes features visible that might have been overlooked before.
AGRICULTURE, FORESTRY MANAGEMENT AND PLANNING
In agriculture and forestry, LiDAR is used to create 3D elevation maps of a certain area. LiDAR technology can be used to recognize areas which require more fertilizers or water. In forestry, LiDAR can be used to identify trees that have a broken tip or should be removed due to safety risks.
These uses save cost of labor, time and money. LiDAR technology is also considered a safer option. For example, after a storm, it is safer to use a drone to capture a forest area than to send people to survey damages. There exists a risk that an unstable tree could suddenly fall and hit someone.
ARCHAEOLOGY AND BUILDING CONSTRUCTION
In archaeology LiDAR is used to aid in the planning of field campaigns, mapping features beneath forest canopy, and providing an overview of broad, continuous features that may be indistinguishable from the ground. Archeologists can also use LiDAR to create a high-resolution Digital Elevation Model (DEM) that reveals micro-topography which is often hidden by vegetation. Thanks to LiDAR, Roman roads, forts and Iron Age enclosures, even more recent history such as trenches, and POW camps have been discovered.
In construction, LiDAR has played a large industry role. Steep costs and minimal tolerances are some of the features common in this industry. The use of LiDAR has reduced costs as LiDAR enables the creation of accurate 3D Models of the existing space. It also makes it easier to perform accurate quality assurance and to spot errors in the very early stage.
MODELLING POLLUTION
The first application for LiDAR was to use it as a tool to measure clouds and pollution. LiDAR can be used to detect carbon dioxide, Sulphur dioxide and Methane, as the LiDAR wavelength is considerably short. It can operate in ultraviolet, visible region or near infrared.
The information gathered with LiDAR can be used to create a pollutant density map from a certain area. This map can help decision-makers to make better plans and create healthier cities, for example.
HYDROGRAPHIC SURVEY
Hydrographic Survey means the science of measuring features affecting maritime navigation, marine construction, dredging, offshore oil exploration and drilling. In these activities it is important to know the exact position of the coastline and shallow waters. The technique used to measure these is called Bathymetric LiDAR.
The way Bathymetric LiDAR works is to let green light of the LiDAR penetrate water. From this information one can create an accurate 3D model of the underwater terrain. For example, the underwater information gathered from a river enables to understand the depth, width and flow of the water. This information is used to monitor flooding.
AUTONOMOUS VEHICLES
LiDAR is the eye of autonomous vehicles. LiDAR is used to create an accurate 3D representation of the surrounding area by measuring the speed of light and the distance covered by it. The 3D representation monitors the distance of other vehicles and surroundings. With this information, the autonomous vehicle’s command system can take over the brakes, slow down, stop the vehicle and allows the car to accelerate when the road is clear.
SPACE EXPEDITIONS
Since the successful use of LiDAR technology in a space expedition in 1971, space agencies are still using LiDAR for various tasks. For example, NASA uses LiDAR as the key technology to safely land their lunar-landing vehicles and robotics.
LiDAR IN THE NEAR FUTURE
Now that we know the basics about LiDAR and how it is used, you may be wondering what will happen next.
As LiDAR is incredibly accurate and the details gathered from the point clouds have become an essential component of many applications, it is safe to assume that LiDAR is here to stay.
As LiDAR data supply can have multiple uses across industries, it makes it an incredibly cost-effective way of providing highly accurate raw data. When LiDAR technology became commercially available during the 1990s, it was considered expensive and cumbersome. During recent years LiDAR technology has become a vital tool to cut expenses. The LiDAR sensors have become less expensive as demand has increased.
It has been forecast that LiDAR will become as widespread as other geographic information systems, such as mapping and aerial photography, in the coming years.
The incredible accuracy and detail of LiDAR makes it an essential component of many applications that help inform local authorities and other land management organizations in their areas of responsibility. One LiDAR data supply can have multiple uses across many departments ranging from flood mapping, urban modelling, renewable energy, construction, infrastructure planning to archaeology. These multiple applications make LiDAR an incredibly cost-effective way of working.
As the technology became cheaper, the number of LiDAR applications have rapidly expanded. The use of LiDAR within a wide scope of organizations, including local governmental agencies, is growing rapidly. The growth is fueled by increased awareness of LiDAR’s potential benefits. Eventually, LiDAR will become as widespread as other Geographic information, such as mapping and aerial photography. LiDAR is an evolving, up and coming technology. Stay tuned for more LiDAR news.
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