A varied, 1,800 year history stretches across the island of Inchkeith, located in the Firth of Forth off the shores of Edinburgh.
Now a scheduled monument, the 57 acre island has been home to many uses through time.
From the shore, the most prominent feature on the island is the lighthouse, constructed in 1804 and still in operation.
The last major activity on the island took place during the 2nd World War, when around 900 people were stationed there to defend the Forth Bridges and the Rosyth Dockyard.
During this time, the existing defences were extended and expanded, and the island was transformed into a fortress. Gun emplacements, capable of anti air and anti ship defence, were placed in multiple locations, with supporting structures scattered across the small landscape.
Seen from the air, the assortment of boxy structures resemble a crudely created virtual environment, where structures and geography are juxtaposed against each other awkwardly.
What remains of those defences today are complex structures with underground systems similar to a warren or ants nest. Questionable construction techniques are in use everywhere, breaking away as the weather stretches their ability to resist collapse.
But the ruins still create a deeply engaging connection with the past. The larger structures tell their stories, drawing your curiosity and inviting you to ask questions about their previous roles.
UAV 365 were honoured to be able to experience and explore this fascinating place.
Read on to learn about the methods we used and the challenges we faced.
Survey the 57 acre island.
The external survey was carried out using the DJI Matrice 210 V2 with a Zenmuse X7 sensor and various lens focal lengths.
The majority of the mapping flights were pre-programmed using the latest version of Hammer, a flight control application. It was not possible to cover all areas of the island using this software so for specific shots or sections that required flying in close proximity to the cliffs, flight control was handled manually.
Ground control points were deployed to ensure the final model was accurately geolocated and future comparisons could be made.
An overflight was also carried out using the DJI Phantom 4 RTK drone after the main mission concluded. This provided a supplementary dataset to measure geolocation data against.
Survey four of the key structure groups present on the island.
Internal drone based photogrammetry was carried out using the Flyability Elios 2, and then combined with external drone and ground based photogrammetry.
Why did we use an internal drone instead of a terrestrial laser scanner? This will become clear in the next section.
The drone operation requires about 8 days on site.
Access is via a small boat which leaves the harbour at 7am and returns at 3pm.
When you arrive at the island, the boat will offer you up to a harbour wall with a solitary, weather beaten ladder. You and all of your kit need to safely ascend the ladder, ideally without dropping into the water below.
The island has no facilities in place; there is no power for battery charging; no fresh water; no formal shelter; and emergency medical help is a considerable distance away.
All island movement is on foot so you need to be ready to get the heart rate up as you manage the baggage of drones, batteries and supporting equipment between the two of you over the undulating and uncertain terrain.
From the 12th century onwards structures have been built up, buried, modified and degraded, and the ground you are walking on may be grass, rusted steel, a concrete roof or a concealed drop.
Almost all of the structures are unsafe, several of them degrading with every storm that hits the island.
There are no accurate maps or drawings to plan the underground flights – no one knows what’s in there and the chance of drone signal loss is high.
There is potential to disturb gulls and other sea birds, as well as seals who enjoy the waters around the island. If the gulls are suitably disturbed, they may attack your drone. In peak breeding season, thousands of birds call the island home – flying at this time is not an option, which eliminates the summer months.
For the month of November the beaches and harbour area shelter seals raising their young. Disturbing them can be catastrophic, as a stampede of adult seals moving suddenly to the water can cause severe harm to the young pups on the beach.
In the underground structures fragments of decomposing plastic, discarded by the wind, wait to throw themselves mercilessly at the internal drone, blocking the propellers or wrapping like an octopus around the protective cage, impeding airflow.
Decades of dust, accumulated from bird nesting and general degradation, are disturbed by the drone turbulence, reducing visibility and testing the dust proof lighting of the Elios 2 to the limit.
In the deeper chambers, the darkness is complete, and the silence is deafening.
If you lose the drone, finding it will not be easy.
It’s an eerie place, scary even, but completely and totally addicting.