Drone survey maps historic Alnwick tower

A drone has been used to build a highly-detailed 3D model of the Bondgate Tower in Alnwick.

Thursday, 10th February 2022, 10:00 am
GIS specialist Ben Sangster (right) and Kyle Hodgson, senior surveyor at the Three Sixty Group.
GIS specialist Ben Sangster (right) and Kyle Hodgson, senior surveyor at the Three Sixty Group.

The condition of the 15th century monument has been described by Historic England as 'very bad' and 'at immediate risk of further rapid deterioration or loss of fabric'.

High-resolution imagery of the entire gatehouse was collected during the drone survey to create an accurate and realistic digital reconstruction which will be used for condition-based inspection and to formulate an ongoing maintenance plan.

The one-day survey was completed by Kyle Hodgson, senior surveyor at the Three Sixty Group, on behalf of the tower's custodians, the Northumberland Estates.

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Emma Gledson, senior building surveyor for Northumberland Estates, said: "The 3D model and drawings are of exceptional quality, providing a very clear and accurate snapshot in time of Bondgate Tower.

"The data 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.

"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.

"The drawings will allow the Estate to produce accurate records of defects and repairs carried out.”

A high-resolution 3D model of Bondgate Tower.

The model is particularly useful for up-close inspection. The crumbling stonework can be clearly seen in ultra-close and highly-detailed visuals within the model, enabling inspectors to get a really decisive view of the situation - brick-by-brick.

Kyle said: "The drone was able to collect high-resolution imagery extremely quickly. It provided multiple angles - covering various perspectives and accessing hard-to-reach sections, like the roof - to build a robust 3D model to enable a full review of the structure.”

The drone and the high-resolution camera was supplied by heliguy, based in North Shields.

Ben Sansgter, GIS specialist at heliguy, said: “Drones have transformed the surveying industry, enabling the collection of accurate and detailed data in a safe and efficient way.

The model gives a view of the Bondgate Tower roof.

“This was a great example of new and innovative technology being used to protect old and historic monuments.”