This incredible model shows the capabilities of the DJI Zenmuse P1 photogrammetrycamera and the benefit of using drones for heritage conservation.
The 45MP full-frame sensor – integrated with the DJI M300 RTK drone – capturedhigh-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 aprogramme of maintenance and repairs. It is also a valuable asset for heritagedocumentation.
The project showed the value of utilising drones for conservation mapping: The M300-P1collected the highly-accurate and extremely detailed imagery in less than a day, accessingall 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, onbehalf of the tower’s custodians, the Northumberland Estates. Three Sixty Group’s dronepartner, heliguyTM, supplied the M300 RTK and P1 and in-house GIS specialist BenSangster provided Kyle with workflow support during the mapping mission.
Emma Gledson, Senior Building Surveyor for the Northumberland Estates, said: “The 3Dmodel and drawings prepared by Three Sixty Group are of exceptional quality, providing avery clear and accurate snapshot in time of Bondgate Tower.
“The model allows us to inspect the Tower with accurate detail, which we would otherwisestruggle 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 andincreases 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 realitycapture: 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 deterioratingcondition 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, enablinginspectors 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-reachplaces – without the costly, time-consuming and potentially dangerous process of usingscaffolding 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 itwas a lot safer and quicker to collect the data, and allowed me to capture areas of thebuilding which might not have been possible using alternative methods.
“The drone was also able to provide multiple angles – covering various perspectives – toensure 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 seriousmanpower and a laborious workflow to cover multiple angles.”
The drone collected the imagery in less than a day. This was particularly useful consideringthe road which the tower straddles was closed for inspection.
Following the flights, Kyle uploaded the data into post-processing software to create theultra-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 impressivevisuals to build a super-realistic 3D model which can be used for asset management andheritage documentation.”
heliguyTM in-house surveyor, Ben Sangster, said: “The P1 has become afirm 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 datacollection and the survey in Alnwick demonstrated how drones can be utilised forconservation.”
Emma Gledson, from the Estates, added: “The on-site survey was carried out in a shortspace of time and with great professionalism at all times.
“The data is and is going to prove invaluable moving forward with monitoring andmaintaining the Scheduled Monument, which unfortunately is prone to vehicle impactdamage due to being located on a main vehicular route through Alnwick town centre.”
