What Is LiDAR and Why Do We Use It?
Seeing Beyond What the Eye Can See
When most people think of drone surveying, they picture aerial photographs. Photography is useful and has its place, but there are situations where an image alone doesn’t tell the whole story. That’s where LiDAR comes in.
LiDAR (Light Detection and Ranging) uses laser pulses to accurately measure the shape and position of the ground and everything on it. By collecting over a million measurements every second, it lets us build highly detailed three-dimensional models of the land. LiDAR is one of several tools our UAV team uses alongside standard drone photography. See how the two compare in our drone surveying article.
Video: Mark Rober / CrunchLabs — demonstrating LiDAR technology.
How Does LiDAR Work?
LiDAR fires laser pulses at the ground and measures how long each pulse takes to bounce back to the sensor. Since the speed of light is a known constant, the system can calculate the precise position of millions of individual points in space. The result is called a point cloud, a three-dimensional dataset of millions of measured points representing ground surfaces, buildings, vegetation, fences, roads, powerlines, and other structures. Every point carries a real-world coordinate, so it can be measured and analysed rather than just looked at.
Why Not Just Use Aerial Photography?
Photography and LiDAR are often used together, but they do different jobs. A photograph shows what something looks like. LiDAR measures where it actually is. A photo might show a paddock covered in long grass; LiDAR can often see straight through that vegetation to the actual ground surface underneath and model the real terrain. This distinction matters a lot for topographic surveys, flood modelling, engineering design, subdivision planning, infrastructure projects, and earthworks calculations, all of which depend on knowing the true shape of the ground, not just what it looks like from above.
What Makes LiDAR Different?
The biggest advantage of LiDAR is sheer volume and density of information. A single survey can generate hundreds of millions of points across a site, which lets us build:
Detailed terrain models — an accurate picture of existing ground levels across large areas, critical for subdivisions, drainage design, earthworks, and infrastructure planning.
Contour plans — LiDAR data processes cleanly into contour maps, making slopes, falls, and drainage patterns much easier to read and design around.
Vegetation analysis — LiDAR can separate vegetation from the terrain underneath it, which is useful on sites where standard aerial imagery simply can’t show the ground.
Asset mapping — roads, buildings, culverts, fences, and powerlines can all be captured within a single dataset, rather than surveyed separately.
When Do We Use LiDAR?
Not every project needs it, but it earns its place when the site is large (conventional methods alone can take a long time to cover big areas efficiently), when there’s moderate vegetation cover (where photography struggles to show the actual ground), when detailed topographic information is required for engineering or planning, or when fast data collection matters and there’s a lot of ground to cover in a short window.
What Do We Actually Get From It?
The final deliverable is almost never a raw point cloud. Most clients don’t need (or want) millions of individual points, they need something usable. Depending on the project, LiDAR data gets turned into topographic survey plans, contour maps, feature surveys, surface models, earthworks calculations, and engineering or subdivision planning information. The goal is not just to collect data. It’s to produce information that is useful for design and analysis.
Is LiDAR Always the Best Option?
No. It’s a powerful tool, but not the right one for every job. Smaller sites are often surveyed more efficiently with conventional methods. Dense vegetation can still limit results, if laser pulses can’t reach the ground, LiDAR can’t show you what’s there. LiDAR is not an X-ray. And for cadastral surveys, LiDAR doesn’t replace traditional surveying techniques. That’s a different discipline requiring its own precision and methodology. As with any survey technology, the right tool depends on what the project actually needs.
The Important Bit: The Data Is Only the Beginning
Modern drone mounted LiDAR systems make collecting LiDAR data easier than ever, but owning a sensor doesn’t automatically produce useful information. The real value comes from establishing accurate survey control, verifying that accuracy, processing the data correctly, removing errors and noise, interpreting the results, and producing outputs actually suitable for design, consent, engineering, and construction. The sensor collects the information. The surveyor makes sure it can be trusted, that’s the difference between a visually impressive model and a dataset you can actually build a decision on.
Get in Touch
If you’re planning a project and want to know whether LiDAR is the right fit for your site, get in touch. We’ll talk you through what it can offer for your specific project and how we ensure the results are accurate enough to build on.