Laser Scanning vs LiDAR: Key Differences and Applications

In surveying, construction, and 3D mapping, laser scanning and LiDAR (Light Detection and Ranging) are revolutionary technologies, known for their ability to capture detailed data and create intricate and accurate representations of physical environments — all with a high degree of accuracy. Both instruments use laser technology, however, they do have some distinctive differences and […]

In surveying, construction, and 3D mapping, laser scanning and LiDAR (Light Detection and Ranging) are revolutionary technologies, known for their ability to capture detailed data and create intricate and accurate representations of physical environments — all with a high degree of accuracy. Both instruments use laser technology, however, they do have some distinctive differences and are each better suited to different applications. In this article, we’ll delve into the mechanisms of both laser scanning and LiDAR, and break down their similarities and differences.

What Is Laser Scanning?

Laser scanning is a method of capturing precise, three-dimensional data of objects, structures, or environments. By systematically collecting millions of data points from a physical space, laser scanners generate a “point cloud” – a dense array of points that can be used to construct a digital 3D model. This model replicates the dimensions and geometry of the scanned object or area, allowing surveyors and engineers to analyse and measure features in great detail.

Laser scanning is a valuable technology, used in industries such as surveying, where high precision, speed, and detail are critical. Because it can create accurate, high-resolution 3D models, 3D scanning is ideally suited for use in construction, architecture and urban planning.

How Does Laser Scanning Work? 

Laser scanning uses a laser emitter that sends out pulses of laser light towards a surface. The laser beams then reflect off the surface and return to the scanner, where the time taken for the pulses to travel back is recorded. This process, known as “time of flight,” is used to calculate the distance between the scanner and the target. By rotating the laser scanner in a 360-degree arc and continuously pulsing, the scanner captures data points from multiple angles, covering a wide field of view to form a comprehensive 3D representation of the environment.

3D scanning is often used in construction projects, historical preservation, and industrial design, where exact measurements are required for the sake of safety, as well as structural integrity.

What is LiDAR?

LiDAR (Light Detection and Ranging) is a remote sensing technology often used for large-scale data collection. Unlike laser scanning, which is more focused on close-range detail, LiDAR can be positioned on aerial, terrestrial, and mobile systems, to gather spatial data over large areas. It is highly valuable in fields such as topographic mapping, environmental management, and infrastructure planning.

What Does LiDAR Stand For? 

LiDAR stands for ‘Light Detection and Ranging’. As a form of remote sensing, LiDAR emits its own penetrating laser light pulses and does not depend on ambient light, meaning it can be used both during the day and night.

How Does LiDAR Work? 

Similar to 3D scanning, LiDAR works by emitting pulses of laser light and measuring the time taken for the light to bounce back from a surface. These “time of flight” measurements calculate distances with precision. However, LiDAR systems are often capable of emitting thousands or even millions of pulses per second, creating a rapid and comprehensive scan of large environments. This results in large-scale point cloud datasets, which can be processed to create 3D digital models of the area.

Uses of LiDAR 

LiDAR is used in topographic mapping, floodplain modelling, forestry, and city planning, among other professions. One of its significant advantages is its ability to permeate vegetation, allowing it to capture the ground surface even in heavily forested areas. This capability has made it a very useful tool in environmental management.

LiDAR’s flexibility in terms of how it can be used, and its adaptability to different environmental conditions mean, it is highly useful in large-scale projects that require speedy and accurate spatial data acquisition.

What Are the Differences between Laser Scanning and Lidar?

Although laser scanning and LiDAR are sometimes used interchangeably due to their shared dependence on laser pulses, they actually serve different purposes based on their scale, platform, and typical application. Below, we explore some of the main differences and similarities between these technologies.

Is Laser Scanning the Same as LiDAR? 

No, laser scanning and LiDAR are slightly different. Laser scanning is primarily focused on creating highly detailed, small-scale 3D models, meaning it is often used for close-range applications where intricate detail is necessary, such as documenting building interiors or industrial components. LiDAR, meanwhile, excels in large-scale mapping, and is often used to cover vast outdoor areas like forests, rivers, or whole urban landscapes. LiDAR is therefore more versatile for mapping terrain, while laser scanning is ideal for projects requiring close-up precision.

Can LiDAR Be Used as a 3D Scanner? 

Yes, LiDAR can be used as a 3D scanner, especially for large-scale mapping and topography. However, for close-range applications that require more precise and intricate details, 3D laser scanning is often the preferred option due to its higher resolution. LiDAR’s strength lies in its ability to quickly capture extensive datasets over large distances, while laser scanning has an advantage when it comes to representing detail at a smaller scale.

Terrestrial Laser Scanning vs LiDAR

Terrestrial applications of both laser scanning and LiDAR enable high-resolution mapping of structures and landscapes. However, their specific functionalities vary, as do their best-use cases:

Terrestrial Laser Scanning (TLS) 

Terrestrial laser scanning is highly effective for detailed, close-range projects, such as documenting the layout of buildings, monitoring structural changes over time, or capturing minute architectural details. Typically, TLS systems are set up on tripods and scan from a fixed location, covering a specific area in a single sweep. This approach allows for in-depth, precise data collection, making TLS a popular choice in construction, building inspections, and heritage conservation.

Terrestrial LiDAR 

Terrestrial LiDAR, which may be mounted on vehicles or stationary platforms, is designed to capture broader landscape data. Unlike TLS, terrestrial LiDAR is often mobile, allowing it to survey extensive areas, such as railways, road networks, or industrial facilities, with high efficiency. It’s particularly useful for large-scale projects where a comprehensive overview is more important than minute details.

Airborne Laser Scanning vs LiDAR

One of the main advantages of LiDAR is its suitability for aerial applications. Airborne laser scanning allows rapid data collection across vast areas, significantly benefiting industries such as environmental monitoring and urban planning.

Airborne Laser Scanning (ALS) 

Airborne laser scanning is used on aircraft, helicopters, or drones to capture topographical data from above. This approach allows ALS to map large areas efficiently, including hard-to-reach areas like mountain ranges or flood zones. ALS can also penetrate foliage, meaning it can be used for forestry studies and conservation projects. It’s often used in creating Digital Elevation Models (DEMs), which are essential for flood modelling, hydrological studies, and land-use planning.

Airborne LiDAR 

Similar to ALS, airborne LiDAR provides an aerial mapping solution but can cover even larger areas with higher point density, especially when used in conjunction with advanced sensor technologies. It is often used to generate topographic maps, assess vegetation height and density. It can also study and analyse urban infrastructure. Airborne LiDAR systems, typically positioned on planes or helicopters, can achieve a high level of accuracy over wide regions, providing useful data for large-scale environmental or infrastructural projects.

Limitations of Laser Scanning

While laser scanning is widely relied on for its precision, it has certain limitations that make it less suited to some projects. These include:

  • Range constraints – Laser scanning is typically limited to short to mid-range distances (up to around 360m with the more advanced instruments), which makes it less effective for large-scale or wide-area applications. Its strength is in capturing detailed models of smaller, confined spaces rather than expansive landscapes.
  • Sensitivity to ambient conditions – Laser scanners can be affected by external factors, such as sunlight, rain, or fog, which can impact their accuracy. For this reason, laser scanning is often more effective indoors or in controlled environments where ambient conditions can be managed.
  • Data size and processing requirements – Laser scanning generates very large data files, which demand substantial storage space and processing power. This can make data management a challenge, especially on projects that require frequent scans and checks. However, cloud-sharing platforms are making the sharing of these datasets far more straightforward.

Limitations of LiDAR

Although powerful for extensive data collection, LiDAR technology also has a few drawbacks:

  • Cost considerations – LiDAR systems and the associated data processing can be expensive, often requiring specialised equipment and software. This makes LiDAR a considerable investment, which is especially a drawback for smaller projects with less substantial budgets.
  • Data complexity and processing needs – LiDAR datasets are often expansive and complex, requiring high-powered software and technical expertise for effective analysis. The volume of data can be challenging for organisations without the necessary resources for extensive processing.
  • Resolution and detail constraints – While LiDAR can effectively capture wide-scale environments, it sometimes lacks the granular detail required in close-range applications. This makes it less ideal for projects that demand high-resolution data in small, confined areas. In these cases, laser scanning is preferred. 

Conclusion

Laser scanning and LiDAR are both game-changing technologies that have transformed surveying, construction, and environmental management. When it comes to choosing between laser scanning and LiDAR, the better option depends on the project’s specific needs, including the required scale, level of detail, and budget. Laser scanning is better suited to projects that require detailed, close-range 3D modelling, particularly in confined environments or for precise architectural analysis. LiDAR, by contrast, excels in large-scale mapping and is better suited to vast, outdoor environments, such as forests, urban areas, and infrastructure networks.