Cutting Through the Noise: The Different Types of Laser Scanning and What They Deliver

11th November, '25

Laser scanning has become one of the most powerful tools in modern surveying. But while many people have heard of it, fewer truly understand the different types of laser scanning available – or how each one can transform raw environments into actionable data.

At Tri-Tech, we draw on three core laser scanning methods: terrestrial, SLAM and UAV-based LiDAR.

Terrestrial laser scanning (TLS):

The ‘Tripod Scanner’ that most people picture when they hear the term terrestrial scanning. Mounted in a static position, these scanners capture a 360 sweep of its surroundings by firing millions of laser pulses per second. These pulses reflect off surfaces and are recorded as data points, building up a dense point cloud of the environment.

Advantages

Unmatched accuracy; millimetre precision across static or semi-static sites.

Ideal for capturing fine architectural or structural detail

Produces datasets robust enough for heritage preservation and BIM workflows

Outputs

High-resolution point clouds

Measured building survey drawings

BIM-ready 3D models

Structural condition reports

SLAM Scanners:

Unlike static terrestrial scanners, SLAM scanners are more mobile and can be handheld or mounted to other equipment. Using this scanner, surveyors are able to walk through a space while continuously scanning, due to continuous positioning recalibration that builds a live 3D data set.

Advantages

Speed - entire buildings or overgrown areas can be captured in a fraction of the time

Works in complex, obstructed or confined spaces (tunnels, industrial plants, etc)

Flexible - can we used both indoors and outdoors

Outputs

Rapid point clouds

As-built 3D models for facilities or asset management

Quick surveys for planning or renovation projects

UAV/ Drone based Laser scanning (LiDAR)

LiDAR sensors mounted on UAVs fire pulses of light towards the ground, measuring the time it takes for the signal to return. By repeating this thousands of times per second while the drone flies over, the system builds a highly accurate model of the landscape.

Advantages

Coverage at scale - perfect for large, open or inaccessible sites

Penetrates through vegetation to map the bare earth beneath

Reduces risk by capturing data from the air instead of putting surveyors in hazardous terrain

Outputs

Extensive point clouds

Digital Terrain Models (DTMs) and Digital Surface Models (DSMs)

Volumetric analysis e.g. stockpiles, excavation progress

Change detection monitoring over time

WHY the right scanner matters

Our expertise lies in operating these tools, and knowing when to deploy each one or combine them. For example:

A heritage site might require TLS for millimetre-precise detail on facades, supplemented by SLAM for interior corridors.
A Quarry may benefit from UAV LiDAR for overall coverage, tied into a TLS control network for ultimate accuracy.
A city redevelopment could integrate all three methods to create a complete, multi-layered data set.

The outputs are as diverse as the methods themselves: from BIM-ready models and measured survey drawings to terrain maps and volumetric calculations, laser scanning gives clients the confidence that every decision is grounded in data.

Laser Scanning is rewriting how we plan, preserve and build. But the real value isn’t just in the technology, it’s in choosing the right approach for the right project. By tailoring our methodology, we give clients the clarity they need to plan confidently, save time, reduce risks and ultimately deliver projects that succeed.