Open Sky Photography · Drone survey guides
Drone mapping deliverables: orthomosaic, point cloud or 3D model?
The right drone mapping deliverable depends on what your team needs to do with it. A model that is useful for a presentation may not be suitable for measurement or design. Before commissioning a site in Scotland, agree the intended use, required accuracy and software that will receive the data.
This guide explains the questions to ask when choosing between an orthomosaic, point cloud and textured 3D model.
Orthomosaic: a plan view of the site
An orthomosaic combines aerial imagery into a corrected plan-style image. It can help a project team review visible site features, communicate a layout and compare capture dates. Ask what area is covered, the output resolution and how the file will be supplied.
If you plan to overlay the image with other spatial data, agree the coordinate system and required accuracy first. A sharp-looking image should not be treated as evidence that a particular measurement tolerance has been achieved.
Point cloud: spatial data for a technical workflow
A point cloud represents surfaces as a collection of points in three-dimensional space. Its usefulness depends on capture coverage, processing, the subject and the needs of the receiving software. Ask the person who will use it to specify accepted formats and what features must be represented.
Photogrammetry derives information from overlapping photographs. It does not guarantee a complete record of every surface: occluded areas or surfaces that are difficult to reconstruct may need another capture approach. Explain where gaps would affect your intended use.
Textured 3D model: a way to explore and communicate
A textured model can help people understand the shape and appearance of a building or landscape. It may be useful for project discussions, presentation or a visual record. Ask whether the handover is a downloadable model, a viewer or another agreed format, and what software or access is needed.
If measurements are required, state them explicitly. Visual realism and measurement reliability are different requirements, and a model produced for presentation should not quietly become the basis for technical decisions.
Agree accuracy and validation before the flight
Give the operator the tolerance your project requires and explain how the data will be used. Ask how positioning, control and independent checks will support that requirement, and what evidence will be included in the handover. Do not rely solely on a camera specification or the presence of RTK positioning as proof of the accuracy of the finished dataset.
It is also useful to distinguish detail or resolution from positional accuracy. The ability to see a small feature does not, by itself, show that its coordinates or dimensions meet your project requirements.
A commissioning checklist for your technical team
- Site boundary and features that must be captured.
- Intended use: communication, comparison, measurement or design.
- Required horizontal and vertical tolerances, where relevant.
- Coordinate system, height reference, units and file formats.
- Required control, checks and reporting of achieved quality.
- Delivery date, software compatibility and any access arrangements.
- How exclusions, coverage gaps and limitations will be documented.
Send this brief to the person receiving the data before booking. A short compatibility check can prevent a technically substantial output arriving in a format the project team cannot use.
Choose the scope around the result
Open Sky Photography’s drone mapping and photogrammetry service covers enquiries for orthomosaics, point clouds and 3D models in Scotland, with requirements agreed before capture. If you mainly need a visual progress record, construction monitoring photographs may be a simpler brief.
Send your site location, intended use, required outputs and any accuracy specification. See our deliverables and quotation guide for the next step.
