This incredible model shows the capabilities of the DJI Zenmuse P1 photogrammetry
camera and the benefit of using drones for heritage conservation.

The 45MP full-frame sensor – integrated with the DJI M300 RTK drone – captured
high-resolution imagery to build the extremely detailed digital representation of the Bondgate Tower, in Alnwick, Northumberland, UK.

The aerial survey was conducted as part of efforts to preserve the 15th century gatehouse,
which is on Historic England’s Heritage At Risk register and in danger of collapse.

Experts will now use the 3D model to conduct condition-based inspection, to shape a
programme of maintenance and repairs. It is also a valuable asset for heritage
documentation.

The project showed the value of utilising drones for conservation mapping: The M300-P1
collected the highly-accurate and extremely detailed imagery in less than a day, accessing
all parts of the Grade I-listed structure without the need for rope access or scaffolding –
improving safety, and offering a more sensitive method of data collection.

The survey was conducted by Kyle Hodgson, Senior Surveyor at the Three Sixty Group, on
behalf of the tower’s custodians, the Northumberland Estates. Three Sixty Group’s drone
partner, heliguyTM, supplied the M300 RTK and P1 and in-house GIS specialist Ben
Sangster provided Kyle with workflow support during the mapping mission.

Emma Gledson, Senior Building Surveyor for the Northumberland Estates, said: “The 3D
model and drawings prepared by Three Sixty Group are of exceptional quality, providing a
very clear and accurate snapshot in time of Bondgate Tower.

“The model allows us to inspect the Tower with accurate detail, which we would otherwise
struggle to do without installing a scaffold structure, therefore saving time and money. It will allow the Estate to produce accurate records of defects and repairs carried out.”

Building High-quality 3D Models With The P1

The P1 photogrammetry camera has been a stellar addition to the drone surveying market,
not least because of its 45MP full-frame sensor which collects high-resolution data and
increases mapping efficiency by capturing more data in each shot.

The quality of its image capture helps to build a 3D model which is bordering on reality
capture: Hugely beneficial for inspectors conducting analysis remotely or back in the office.
This quality ensures the model is a robust digital asset for up-close inspection: Crucially, the level of detail never wains when zooming in on sections of the wall – as this series of images shows.

This up-close clarity is especially important for the Bondgate Tower as its deteriorating
condition has been caused, in the main, by high-sided vehicles colliding with the archway.
The tower’s crumbling stonework can be clearly seen in this ultra-close visual, enabling
inspectors to get a really decisive view of the situation – brick-by-brick.

And this is another advantage of deploying the drone: Collecting data from hard-to-reach
places – without the costly, time-consuming and potentially dangerous process of using
scaffolding or rope access – to build a fully-fleshed-out model.

Imagine the implications of using manual methods to capture detailed imagery of the tower’s roof, for instance.

Kyle said: “The drone reduced the need for access platforms and rope access, meaning it
was a lot safer and quicker to collect the data, and allowed me to capture areas of the
building which might not have been possible using alternative methods.

“The drone was also able to provide multiple angles – covering various perspectives – to
ensure a robust model was built to provide a full review of the whole structure.

“Traditional methods tend to only provide one angle from the ground up, or involve serious
manpower and a laborious workflow to cover multiple angles.”

The drone collected the imagery in less than a day. This was particularly useful considering
the road which the tower straddles was closed for inspection.

Following the flights, Kyle uploaded the data into post-processing software to create the
ultra-realistic photogrammetry mesh model.

Reflecting on the survey, Kyle said: “The P1 is a great solution. The clarity and resolution are tremendous, surpassing other cameras we have used.
“This plug-and-play solution was easy to set up, a pleasure to use, and captured impressive
visuals to build a super-realistic 3D model which can be used for asset management and
heritage documentation.”

heliguyTM in-house surveyor, Ben Sangster, said: “The P1 has become a
firm favourite for aerial surveyors and it is easy to see why when looking at the 3D model.

“Drone mapping, especially with the M300 RTK and P1, is an efficient method of data
collection and the survey in Alnwick demonstrated how drones can be utilised for
conservation.”

Emma Gledson, from the Estates, added: “The on-site survey was carried out in a short
space of time and with great professionalism at all times.

“The data is and is going to prove invaluable moving forward with monitoring and
maintaining the Scheduled Monument, which unfortunately is prone to vehicle impact
damage due to being located on a main vehicular route through Alnwick town centre.”

By Press