What Are The Different Types Of LiDAR And What Are They Used For?
LiDAR technology is at the core of several different industries and innovations. By bouncing light pulses off of objects, buildings, and surfaces, LiDAR systems measure distances and dimensions.
This technology is used mostly for surveying. For example, LiDAR can be used to survey the topography of natural landscapes and built-up environments.
But there are different types of LiDAR, which vary slightly in the way they work and collect data. Before starting a project, it’s a good idea to learn about the types of LiDAR — so you can choose the right LiDAR for the right application.
Here’s everything you need to know about the types of LiDAR out there.
With airborne LiDAR, the laser scanning system is fixed to an aircraft like a helicopter or drone. Light pulses are sent from the aircraft to the ground, to measure the distances and dimensions of the landscape below.
Advantages of LiDAR Data
Airborne LiDAR systems can scan as long as the aircraft is in the air — and with no real time limitation, you have the opportunity to examine miles and miles of land. So this type of LiDAR is often the best option for scanning projects covering large areas.
Using an aircraft — especially a larger aircraft — can be more costly than using terrestrial LiDAR. But for larger projects, airborne LiDAR could be more cost-effective. This is because airborne LiDAR can cover more ground in a shorter space of time than terrestrial LiDAR — saving time and budget.
Airborne LiDAR also doesn’t have to avoid obstacles on the ground — whereas terrestrial LiDAR systems have to navigate around obstacles like power lines, trees, and signs.
Types of Airborne LiDAR
There are two types of Airborne LiDAR: topographic and bathymetric. While both of these types work in the same way — scanning what lies below from an aircraft — each has different capabilities.
Topographic LiDAR systems scan surfaces, calculating how high above sea level different points on the ground are by collecting the elevation values of the points. The data collected from this laser scanning technique is used for urban planning projects, such as highway or railroad planning, housing developments, and infrastructure.
The point cloud data collected from topographic LiDAR can create topographic maps of the scanned area. Topographic maps show the contouring of the surface through lines and colours. They can depict where land or man-made structures rise and fall, to produce an accurate representation of the landscape.
While topographic LiDAR scans just about any in-land surface, bathymetric LiDAR is more suited to scanning through water.
Bathymetric LiDAR systems are equipped with two lights: an infrared light and a green laser. The infrared light is used to scan water or land surfaces (the shoreline for example), while the green laser can cut through water to scan river and ocean beds. So technically, bathymetric LiDAR can be used to gather coordinates from both land and sea — although those working on coastal projects usually favor it.
Terrestrial LiDAR systems aren’t attached to an aircraft — instead, they’re fixed to a moving vehicle or a tripod on the ground. Rather than scanning down, terrestrial LiDAR systems often scan in several directions with the use of mirrors. This allows them to capture data from all around.
Advantages of Terrestrial LiDAR
It’s often easier to collect contour details from the ground with terrestrial LiDAR than it is to use a drone. So terrestrial LiDAR can work with an airborne system to give a fuller picture. The airborne LiDAR collects a birds’ eye scan of a large area, and then terrestrial LiDAR is used to gain a detailed look at specific sites.
Terrestrial LiDAR can also be used to scan areas airborne lasers can’t reach, such as in buildings or under tree canopies.
Because this laser scanning system is often used in built-up areas with people, the lasers are eye-safe — so there’s no risk of harming anyone with the light.
Types of Terrestrial LiDAR
Mobile LiDAR systems are mounted to moving vehicles such as cars, trains, and boats. Rather than just using one laser, they can have several so they can scan multiple angles at the same time.
This type of LiDAR is a good option for scanning roads and railroads. As the system moves down transport corridors, the LiDAR scanners will scan the road or railroad’s condition, signs, and power lines.
Mobile LiDAR is often used for 3D mapping, as it collects a more dense database of points (coordinates), which can create more detailed 3D images and maps.
Static LiDAR is the only type of LiDAR that isn’t moving. Instead, it’s attached to a static tripod and used to either scan the entire surrounding area or focus on a specific region. Static LiDAR can scan in all directions, including upwards.
The tripod can be moved to different locations once scans are complete, to ensure comprehensive coverage of an area. So the static system — although stationary during scans — is portable.
Static LiDAR is usually used for scanning building interiors or specific outside areas. So it’s a popular tool for engineering, architecture, archaeology and mining projects.