LiDAR (Light Detection and Ranging) uses laser pulses to measure distances and build a precise 3D point cloud of the surveyed area. Where it separates itself from photogrammetry is what it does on vegetated land: the laser can return multiple measurements from a single pulse — top of canopy, mid-canopy layers, and the ground beneath. That last return is how LiDAR recovers bare-earth elevation data through dense hedgerows, tall crops, scrub, and woodland edges.
For any survey where you need to know what the actual ground surface is — drainage design, earthworks calculations, flood modelling, solar farm siting, forestry management — photogrammetry on vegetated land cannot provide that data regardless of how many ground control points are used. LiDAR is the correct tool. Our LiDAR sensor delivers up to five returns per laser pulse and achieves 4 cm vertical accuracy at 150 m altitude.
On hardscape — roads, ploughed fields, construction sites — photogrammetry achieves around 2 cm accuracy and is often faster and more cost-effective. We will tell you which method suits your site before any work begins — or read our guide to choosing the right drone survey for a detailed comparison.
Pre-design topographic surveys for road schemes, drainage networks, flood defence works, and linear infrastructure corridors. On any site with hedgerows, scrub, or uncut verges, a photogrammetric DTM records the vegetation surface — not the ground. LiDAR gives you the bare-earth profile needed to design drainage gradients, calculate earthworks volumes, and tie corridor surveys to Ordnance Datum. As-built surveys of completed earthworks verify cut-and-fill against design intent. Coastal and riverbank profiles capture the true toe of the bank where photogrammetric models are systematically too high.
Field drainage design requires accurate bare-earth topography of the ground beneath the crop, the hedgerow, and the drainage ditch. LiDAR recovers that data on a single flight. Ditch profiles, field-margin slopes, and invert levels that a photogrammetric survey cannot reach through tall vegetation are all captured and classified in the point cloud. For land levelling assessments, soil movement calculations require the true ground surface — not the top of whatever is growing on it. LiDAR is also used for pre-drainage feasibility assessments across larger holdings where fall and catchment boundaries are not immediately obvious from a visual inspection.
A single LiDAR sortie over a forested block returns both the canopy surface and the bare earth beneath it simultaneously. The canopy height model — the difference between the two — gives tree height, density, and volume estimates across the block without ground-truthing every stand. Bare-earth data provides the access road topography and drainage profile needed for harvesting and replanting planning. For coupe boundary surveys, LiDAR resolves the ground surface beneath dense edge vegetation where photogrammetry cannot penetrate. Change detection across repeat surveys tracks canopy growth and identifies areas of die-back or wind damage.
Pre-construction site assessments for solar farms and wind turbine foundations depend on knowing the true ground surface to model drainage, calculate cut-and-fill, and identify areas with problematic gradients. Where the site carries vegetation — rushes, gorse, scrub, or rough grazing — photogrammetry records the vegetation, not the ground, and the error accumulates across the site. LiDAR resolves this on a single flight. Drainage catchment analysis across large energy sites requires bare-earth data tied to the wider catchment — particularly where planning submissions require hydraulic modelling to demonstrate no increase in runoff.
Five returns per laser pulse — our LiDAR sensor recovers ground elevation through hedgerows, tall crops, scrub, and woodland edges where photogrammetry records only canopy height.
A single LiDAR sortie delivers a classified point cloud (LAS/LAZ), digital terrain and surface models, and contour plans at your specified interval.
Our LiDAR sensor captures a 20 MP georeferenced colour orthomosaic on the same flight as the LiDAR scan — no second flight, two spatially consistent datasets.
Combined system accuracy (sensor + RTK + IMU) is 4 cm vertical at 150 m altitude. On hardscape with GCPs, photogrammetry achieves around 2 cm — we recommend the right method for your site.
The sensor's 75° vertical field of view captures the full face of a chimney, retaining wall, or pier from a single flight line at a safe standoff — no multiple passes at varying altitudes.
At 150 m altitude and 15 m/s, our LiDAR sensor covers 2.5 km² per battery — practical for corridor mapping, large farm surveys, and catchment-scale flood modelling.
When the laser hits a tree canopy over open ground, it doesn't return a single reading. It returns up to five: one from the top of the canopy, one or more from mid-canopy layers, and one from the ground. That last return is the bare-earth point — the actual ground surface beneath the vegetation. With a spot size of 4×12 cm at 100 m, our sensor recovers ground points through denser cover than older LiDAR systems allowed. For Irish field surveys with hedgerows, drainage ditches, and uneven scrub, this directly determines whether a usable DTM can be produced.
The sensor also pairs a 20 MP 4/3" RGB mapping camera on the same rigid mount — meaning a single flight delivers both the classified point cloud and a georeferenced colour orthomosaic, spatially consistent with each other and requiring no additional registration work.
The key question is what your site is covered with. On hardscape — roads, buildings, gravel, ploughed fields — photogrammetry achieves around 2 cm accuracy and is often the faster, more cost-effective option. On softscape — tall grass, crops, ferns, hedgerows, forestry — photogrammetry records the top of vegetation, not the ground beneath. Actual ground level may be 10–30 cm lower and is unknowable from the photogrammetric dataset, regardless of how many GCPs are used.
For any project requiring true bare-earth topography — drainage design, earthworks calculations, flood modelling, solar farm siting — LiDAR is the correct instrument. We will confirm the right method for your site before any survey is commissioned.
Every LiDAR survey produces a classified point cloud in LAS/LAZ format, a digital terrain model (DTM) of the bare-earth surface, a digital surface model (DSM) including above-ground features, contour plans at your specified interval, and a survey report with accuracy statement. Where the mission profile includes the LiDAR system's RGB camera, a georeferenced colour orthomosaic is also included. All data is tied to Irish Transverse Mercator (ITM) and Malin Head Ordnance Datum.
LiDAR survey costs depend on site area, accessibility, and required accuracy. We will confirm the right approach and provide a fixed-price quote before any work begins. Contact us to discuss your project.
Summary: Use LIDAR for vegetated areas to get an accurate picture of the bare earth, use photogrammetry if vegetation isn't an issue and you want high-resolution imagery.
LIDAR and photogrammetry are both remote sensing technologies that can be used to create 3D models of the terrain. LIDAR is generally more accurate when it comes to complex terrain, especially when it is heavily vegetated. LIDAR may be more expensive and so may not be the best option for projects with limited budgets or tight timelines. Photogrammetry may be a more cost-effective option that is better suited for projects that require high-resolution imagery or detailed texture mapping. However, there are certain situations where one technology may be more appropriate than the other. Here are some factors to consider when deciding whether to use LiDAR or photogrammetry:
LiDAR is generally considered to be more accurate than photogrammetry, especially when it comes to vertical accuracy. If you need highly precise measurements of elevation, such as for engineering or construction purposes, LiDAR may be the better choice.
LiDAR is better suited for surveying areas with complex terrain, such as dense forests or urban environments, where it can penetrate through vegetation and capture detailed data on the ground surface. Photogrammetry, on the other hand, may struggle in areas with a lot of obstructions or limited visibility.
LiDAR equipment and services are generally more expensive than photogrammetry, which uses cameras and software to create 3D models. If budget is a concern, photogrammetry may be the more cost-effective option.
LiDAR can capture data quickly and efficiently, making it a good choice for projects that require a fast turnaround time. Photogrammetry may require more time for processing and may not be as efficient for large-scale projects.
Finally, consider the specific data requirements of your project. LiDAR can capture information on vegetation, buildings, and other structures that may not be visible with photogrammetry. Photogrammetry may be better suited for projects that require high-resolution imagery or detailed texture mapping.
LiDAR is the correct choice wherever the survey objective requires knowing the true ground surface — not just the surface of whatever covers it. Common applications include:
Pre-design topographic surveys for roads, drainage, and flood defence. Corridor mapping for linear infrastructure. As-built surveys of completed earthworks. Coastal and riverbank profiling where vegetation cover makes photogrammetric DTMs unreliable.
Field drainage design, land levelling assessments, and boundary surveys across farms with tall crops, hedgerows, and drainage features. LiDAR recovers the ditch and field-margin topography that would otherwise be lost in the canopy.
Canopy height models, tree density mapping, and harvesting block planning. LiDAR returns both canopy height and bare-earth data simultaneously, giving forestry managers both the timber volume estimate and the access road topography in a single flight.
Pre-construction site assessments for solar farms and wind turbine foundations where vegetation cover prevents photogrammetric ground modelling. Drainage catchment analysis for large energy sites.
The sensor's 75° vertical field of view allows the full face of a chimney, retaining wall, or pier to be captured from a single flight line at safe standoff — producing a dimensioned point cloud of vertical structures without multiple altitude passes.
Complex surveys and inspections require more than just a pilot. Our engineers can help you scope your requirements and indentify the right approach.