LiDAR, photogrammetry, and magnetometry: when to use each technology in the field

Not every drone survey answers the same question.

In industrial, oilfield, maintenance, or construction operations, it is common to talk about drones as if they were one single solution. But the drone is only the platform. What matters is which sensor is used, which data is captured, and which decision the team needs to support.

LiDAR, photogrammetry, and magnetometry can all be part of the same field intelligence workflow, but each technology observes the site in a different way.

One helps explain the geometry and elevation of the terrain.

Another generates measurable visual maps.

Another detects signals associated with buried metallic infrastructure.

The right question is not: which technology is better?

The right question is: what do I need to know about the site before acting in the field?

The common mistake: asking for a drone survey without defining the decision

In many cases, the problem starts before the flight.

A team needs to excavate, intervene on a line, build a work pad, review an installation, mobilize machinery, or document an area. Then someone asks for a drone survey as if that alone were enough.

But a survey only has value if it is connected to a decision.

It is not the same to need:

• a visual map of the area
• a 3D terrain model
• a high-precision point cloud
• a volume measurement
• an identification of buried metallic anomalies
• a GIS layer for planning
• a pre-excavation review
• construction progress documentation
• a validation of site conditions

Each question requires a different technology or a combination of technologies.

That is why teams need to define the operational problem before they talk about drones.

Photogrammetry: when you need to see, measure, and document the site

Photogrammetry uses aerial imagery to generate measurable products such as orthomosaics, 3D models, and maps of the surveyed area.

It is one of the most useful technologies when teams need a visual representation of the site.

It can help answer questions such as:

• What does the area look like today?
• Where are the access points, equipment, structures, or visible constraints?
• What is the surface condition of the terrain?
• How can the site be documented before or after an intervention?
• What changes are visible between two dates?
• How can a clear view of the site be shared with operations, engineering, or contractors?

Photogrammetry is especially useful for documentation, visual planning, progress tracking, time-based comparison, and base map generation.

In an oilfield or industrial context, it can support:

• documenting well locations
• reviewing right-of-way corridors
• supporting mobilization planning
• generating orthomosaics for operational areas
• recording conditions before and after work
• improving coordination across teams

Its main strength is that it converts imagery into measurable visual maps and models.

But it has an important limitation: it mainly shows what is visible from above.

If the risk is buried or hidden beneath vegetation, structures, or the terrain itself, photogrammetry alone may not be enough.

LiDAR: when you need precision in terrain, elevation, and geometry

LiDAR uses laser pulses to measure distance and generate high-precision point clouds.

Unlike a simple image, LiDAR can produce a detailed geometric representation of terrain, structures, elevations, and surfaces.

It is useful when the team needs to answer questions such as:

• What is the real shape of the terrain?
• What elevations exist across the area?
• How does the surface change in a work zone?
• Where are the slopes, embankments, depressions, or topographic constraints?
• Which structures or physical elements need to be modeled precisely?
• How can a point cloud be generated for engineering, design, or planning?

LiDAR can be especially valuable in projects where topographic and geometric precision is critical.

In industrial or oilfield operations, it can support:

• terrain modeling
• location planning
• slope and access review
• volume measurement
• facility documentation
• point cloud generation
• integration with engineering or GIS workflows
• analysis of physical site conditions

Its main strength is spatial precision.

But LiDAR does not answer every question either. It can explain a great deal about the surface and geometry, but it does not necessarily identify a buried metallic line or a ferromagnetic anomaly below the ground on its own.

That requires another data layer.

Magnetometry: when you need to detect signals from buried metallic infrastructure

Magnetometry measures variations in the magnetic field.

When buried ferromagnetic materials are present, such as steel, pipelines, casing, abandoned wellheads, metallic remnants, or undocumented infrastructure, they can generate detectable anomalies.

In oilfield operations, aerial magnetometry can help answer questions such as:

• Are there signals of buried metallic infrastructure?
• Are there alignments compatible with buried pipelines or lines?
• Are there metallic anomalies in the area where excavation is planned?
• Could there be casing remnants or abandoned wellheads?
• Which zones require review or validation before intervention?
• Where should teams be more careful before mobilizing equipment?

Magnetometry is especially useful when the problem is not visible on the surface.

It can support work such as:

• excavations in mature fields
• pre-intervention reviews for pipelines or lines
• well pad preparation
• identification of metallic anomalies
• review of areas with incomplete drawings
• support for maintenance, integrity, or construction teams
• reduction of uncertainty before intervention

Its strength lies in detecting signals associated with ferromagnetic materials.

But teams also need to be clear about its limits: magnetometry does not see everything that is buried. It does not detect non-ferromagnetic materials such as PVC, concrete, fiber optic lines, or certain non-metallic elements in the same way.

And an anomaly should not be interpreted as an absolute identification without technical context and validation.

Its value lies in generating anomaly maps and zones of interest that help prioritize review before action begins.

When to use each one

One simple way to understand the distinction is this.

Photogrammetry

Use it when you need to see, measure, and visually document the site.

LiDAR

Use it when you need geometric precision, elevation, terrain modeling, structure modeling, or point clouds.

Magnetometry

Use it when you need to detect signals associated with buried metallic infrastructure or ferromagnetic anomalies.

Each technology responds to a different layer of reality.

Photogrammetry looks at the visible surface.

LiDAR measures the geometry of the site.

Magnetometry detects magnetic signals associated with ferromagnetic materials.

In real projects, the greatest value often appears when these technologies are combined correctly.

Practical example: before an excavation in a mature field

Suppose a team needs to excavate or intervene in an area inside a mature oilfield.

The available documentation may be incomplete. The terrain may have changed. There may be aging lines, casing remnants, metallic debris, or buried infrastructure that does not appear clearly in the drawings.

In that case, each technology can contribute something different.

Photogrammetry can generate an orthomosaic and document visible site conditions.

LiDAR can help explain elevations, slopes, access routes, surfaces, and terrain geometry.

Magnetometry can detect ferromagnetic anomalies that suggest possible buried metallic infrastructure.

Combining those layers can help operations, engineering, maintenance, or contractors understand the site better before mobilizing equipment or starting work.

It does not eliminate all risk.

But it does reduce uncertainty.

And in field operations, reducing uncertainty before action can prevent delays, rework, damage to existing infrastructure, and decisions made with incomplete information.

It is not about capturing more data, but the right data

One of the most common mistakes in digital and technical projects is assuming that more data always means better decisions.

Not always.

More data can become more noise if it is not connected to an operational question.

A drone survey should begin with the decision the team needs to support.

For example:

If the question is what the area looks like visually, photogrammetry is probably enough.

If the question is what the exact terrain geometry is, LiDAR may be the better option.

If the question is whether buried metallic infrastructure may exist, magnetometry is the most relevant layer.

If the question combines several of those needs, the solution may require several technologies.

The key is to design the survey from the decision backward, not from the sensor forward.

From technology to field intelligence

At StrataIntel, we do not see these technologies as isolated services.

We see them as acquisition layers that can become field intelligence.

That distinction matters.

A drone can capture imagery.

A sensor can capture signals.

Software can process data.

But the value appears when that information is organized into deliverables an operational team can actually use:

• anomaly maps
• orthomosaics
• terrain models
• point clouds
• GIS layers
• prioritized zones
• technical reports
• coordinates for points of interest
• recommendations for field review

The objective is not to produce more complex files.

The objective is to help teams make better decisions before excavation, intervention, construction, maintenance, or equipment mobilization.

How to choose the right technology

Before selecting a technology, it helps to answer a few questions.

What decision needs to be made?

What is currently known about the site?

What information is missing?

Which risks are visible, and which might be buried?

Is the problem visual, geometric, geophysical, or a combination?

What deliverable does the team need in order to act better?

Who will use the information: operations, engineering, maintenance, integrity, EPC, or the contractor?

What level of precision or validation is required?

These questions help teams avoid generic surveys.

They also help design a workflow where each technology has a clear function.

Conclusion

LiDAR, photogrammetry, and magnetometry do not compete with each other.

They answer different questions.

Photogrammetry helps teams see, measure, and document what is visible.

LiDAR helps teams understand site geometry and elevation with precision.

Magnetometry helps teams detect signals associated with buried metallic infrastructure.

In oilfield, industrial, and maintenance operations, the right technology depends on the decision that needs to be made.

That is why the starting point should not be I need a drone.

The starting point should be: what uncertainty do I need to reduce before acting in the field?

At StrataIntel, that is how we understand field intelligence: using drones, sensors, and technical processing to convert the physical reality of a site into useful information for operational decisions.