LiDAR vs. Photogrammetry: Which Does Your Project Need?

What Are LiDAR and Photogrammetry?

Photogrammetry builds 3D measurements from overlapping photos; LiDAR measures distance directly with laser pulses. Both ride on drones. Both produce point clouds and surface models. The physics behind each is different, and that difference — not marketing — should decide which method your project pays for.

Photogrammetry is measurement from photography. A drone flies a grid over the site and takes hundreds of overlapping pictures. Software finds the same features in multiple photos and triangulates their positions, much the way your two eyes judge depth. The result is a georeferenced 3D model of everything the camera could see.

LiDAR (Light Detection and Ranging) is an active sensor. It fires laser pulses at the ground — hundreds of thousands per second — and times each return. Distance comes straight from the speed of light. The result is a point cloud measured directly, with no photos required and no dependence on surface texture or lighting.

How Does Each Method Work From a Drone?

A photogrammetry flight captures overlapping photos on a preplanned grid; a LiDAR flight sweeps a laser scanner across the site while an inertial unit tracks the sensor's every movement. The hardware is different, and so is the processing that follows.

For photogrammetry, the drone flies parallel lines with high overlap between frames, so every point on the ground appears in many photos. Each image is tagged with an RTK- or PPK-corrected position. Processing software matches millions of features across the photo set, reconstructs the camera positions, and builds a dense point cloud, a surface model, and an orthomosaic — a map-accurate aerial photo of the whole site.

For LiDAR, the payload pairs a laser scanner with a GNSS receiver and an inertial measurement unit. After landing, the flight trajectory is corrected (PPK) and every laser return is placed in real-world coordinates. Many pulses return more than once — part of the energy reflects off a leaf, part continues to the ground — which is how LiDAR maps terrain under vegetation. The point cloud is then classified: ground, vegetation, structures, everything else.

Where Does Photogrammetry Win?

Photogrammetry wins on open sites where the camera can see the ground — and it usually wins on cost. If your project is cleared dirt, stockpiles, pavement, or an active construction pad, photogrammetry is normally the right call, and paying for LiDAR adds little.

It also wins wherever the picture itself is the product. Photogrammetry is the only one of the two that produces a true orthomosaic: one map-accurate aerial image of the entire site. That image is the backbone of construction progress monitoring, stockpile documentation, and as-built visual records. LiDAR gives you geometry; photogrammetry gives you geometry plus the photographic evidence a PM can put in front of an owner.

Texture and color matter too. A colorized photogrammetric point cloud looks like the real site, which makes review meetings faster. And because the payload is a camera rather than a laser scanner, drone mapping with photogrammetry generally costs less to fly and process. That cost gap holds across the industry, so on open ground the cheaper option is usually also the correct one.

Where Does LiDAR Win?

LiDAR wins wherever vegetation hides the ground. A camera cannot photograph dirt it cannot see, so photogrammetry over brush, timber, or crops maps the top of the canopy, not the terrain beneath it. LiDAR pulses slip through gaps in foliage, and enough last returns reach the soil to build a true bare-earth DTM.

That single capability drives most LiDAR work: drainage studies, cut-and-fill on wooded parcels, floodplain terrain, and site planning before clearing. Across the Gulf South territory we serve — Texas, Louisiana, and Mississippi — pine, hardwood, and heavy understory cover much of the land, and LiDAR is often the only practical way to get usable ground data without clearing first.

LiDAR also owns corridors and thin structure. Long, narrow targets — pipelines, transmission lines, roadways, levees — fly efficiently with a scanner, and LiDAR picks up wires and poles that photogrammetry routinely misses. It captures canopy height and density for vegetation-encroachment work, and it shrugs off shadows, low sun, and bland surfaces that give photo-matching software trouble. Our LiDAR scanning service page covers what a corridor or terrain deliverable includes.

What Drives Accuracy for Both Methods?

Accuracy comes from positioning, ground control, and flight planning — not from the sensor alone. The same aircraft can produce excellent or useless data depending on how the flight is corrected and checked, so both methods live or die on the same fundamentals.

RTK and PPK corrections tighten the drone's GNSS position from meter-level to centimeter-level, either live in flight (RTK) or after landing (PPK). Ground control points — targets measured on the ground — anchor photogrammetry to the site and let LiDAR be verified. Independent checkpoints, held out of processing, are how any dataset should be tested. skyZenith flies RTK/PPK-positioned aircraft on every mapping and scanning mission.

With that discipline, typical industry results for drone photogrammetry with RTK/PPK and ground control run around 1–3 cm horizontal and 2–5 cm vertical. Typical industry results for drone LiDAR run roughly 3–10 cm vertical, with point densities from tens to several hundred points per square meter depending on altitude and sensor. Treat those as planning figures, not promises — every site, flight, and processing chain is different, and the checkpoints tell the real story.

One boundary worth stating plainly: we deliver mapping and scanning data that supports survey and engineering workflows. Boundary determination, control, and anything else that constitutes surveying stays with your licensed surveyor.

How Do the Deliverables Differ?

Photogrammetry delivers photo-based products; LiDAR delivers classified point clouds and bare-earth terrain. Knowing which files land in your inbox is often the clearest way to pick a method.

From photogrammetry, expect a GeoTIFF orthomosaic, a digital surface model (DSM), a colorized point cloud, and contours cut from the surface. These feed quantity takeoffs, progress documentation, and design overlays directly in CAD and GIS.

From LiDAR, expect a classified LAS/LAZ point cloud — ground, vegetation, structures — plus a bare-earth DTM and contours (DXF/SHP) generated from ground points only. That ground classification is the deliverable photogrammetry cannot honestly produce on a vegetated site.

Our process is the same either way: fly under FAA Part 107, fully insured, with RTK/PPK corrections; process; and deliver engineering-ready files your engineer or surveyor can drop straight into their workflow.

Decision Checklist: Which Should You Choose?

Choose photogrammetry for open sites and visual records; choose LiDAR for vegetated ground, corridors, and canopy; use both when one flight cannot answer every question. Run your project through this list:

• Can you see the ground in an aerial photo? Mostly yes — photogrammetry.
• Do you need an orthophoto or a visual progress record? Photogrammetry.
• Do you need bare-earth terrain under brush or timber? LiDAR.
• Is the target a long corridor — pipeline, powerline, levee, roadway? LiDAR.
• Do you need wires, poles, or canopy structure captured? LiDAR.
• Tight budget on a cleared site? Photogrammetry, and put the savings into ground control.
• Need terrain under trees and a visual record? Fly both; the datasets overlay cleanly.

If the cheaper option covers your deliverables, we will say so — an orthomosaic and DSM answer more construction questions than most people expect. If the site is wooded or the corridor is long, LiDAR earns its cost quickly. Send the site and the deliverables your engineer needs through our quote form or to info@skyzenithdrones.com, and we will recommend one method, the other, or both.