Drone mapping trees with PIX4Dmatic

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A standard survey typically focuses on terrain and boundaries, but in this project, the client wanted to preserve as many trees as possible by designing the building around the existing landscape. This project required the exact location and count of every single tree to allow for nature-first architectural design. We spoke with Federico Bonet, surveyor and owner of Aereal Pro Solutions SL, a drone company specialized in aerial photogrammetry and inspections about the technical hurdles of mapping a dense forest where traditional tools fail.

The raw 3D pointcloud from PIX4Dmatic, of the plot, showing the dense canopy that originally blocked ground-based visibility

To do this, they had to map the exact location and count of every single tree on the property. This allowed the architects to design the building around the nature already there, rather than clearing the land.

They encountered three technical hurdles:

• The thick tree cover made the job tricky
• Limitation of traditional surveying equipment such a total station
• Difficulty in differentiating which trees have been measured and which have not

Using PIX4Dmatic to filter the point cloud, distinguishing between the high canopy (blue) and the ground-level data

The dense canopy made the work extremely difficult. Traditional GPS failed because the branches blocked satellite signals, and standard ground equipment, like total stations, was unusable because the thick vegetation limited visibility to just a few feet. Additionally, the lack of a clear view made it nearly impossible to track which trees had already been measured. To overcome this, the team used a drone to capture the site from above, "stitching" the images together to create a map that was both faster and more accurate than traditional methods.

Pinpointing the exact base of every tree across the site to ensure an accurate count for the architectural design

Capturing trees in 3D requires more than just an overhead view. Federico combined an automated flight—which covers the broad area quickly—with manual piloting to get 'eyes' under the canopy. This 'hybrid' approach ensured they had enough data to pinpoint the base of every trunk, not just the tops of the leaves.

He flew a DJI Mavic 3M with RTK with a nadir and oblique flight,, capturing 649 images. The dataset was processed in PIX4Dmatic with a 0.5 GSD. The crowns were filtered to leave the part of the trunks and from profiles each of the trees of the plot were located. The final delivery is a CAD file with the boundaries, slopes and position of each of the trees. Just one more example of how drone mapping has become part of the day-to-day life of topography.

A profile view used to see through the vegetation, verifying trunk locations and elevations against the ground terrain

“PIX4Dmatic helped us classify the point cloud and create cross-sections to better identify the trunks of the trees present on the plot." - Federico Bonet, Surveyor, Aereal Pro Solutions SL