Share | 12/10/2024
In early 2023, Pete Kelsey, the owner of VCTO Labs, embarked on a pioneering and one-of-a-kind project to gain a comprehensive understanding of Alcatraz Island’s past and present.
The ambitious plan was to thoroughly document every aspect of this landmark, encompassing the historic prison—both inside and out—and its natural surroundings, utilizing cutting-edge technology such as the eBee X drone with a dual multispectral and RGB camera.
The pro-bono project spanned a year, with discussions starting in January 2023 and mapping executed in December 2023. Kelsey assembled a diverse team, including tech giants like Boston Dynamics, Esri or Emesent, utilizing their cutting-edge technology for terrestrial and aerial surveys, involving TLS, SLAM, drone-based LiDAR and photogrammetry.
The collected dataset is so comprehensive that it would be crucial for preservation and future projects, benefiting the U.S. National Park Service, archaeologists from the Golden Gate National Recreation Area, Alcatraz’s biologists, botanists, and Operations and Maintenance (O&M) professionals.
The team spent three weeks on Alcatraz for comprehensive mapping and scanning, even opting to sleep in the prison cells for logistical efficiency.
Utilizing best-in-class technology, the project achieved a comprehensive scan of the island from the air and on land. In addition to the eBee X fixed-wing, tools included the Emesent Hovermap ST-X LiDAR for scanning interiors, the Flyability Elios 3 drone for confined spaces, the Boston Dynamics Spot for accessing restricted areas, RIEGL Laser Measurement Systems scanner, and more.
For project lead Pete, establishing survey control was crucial to hold together the diverse data layers from different systems. This was handled by the international company PCL Construction, ensuring a remarkable 3 mm accuracy across the network, contributing to data coherence and alignment.
Alcatraz Island, as part of the National Park System under the U.S. Department of the Interior, had strict compliance requirements for the systems used. The eBee X was selected for the photogrammetry part due to its alignment with these requirements; it is NDAA-compliant and the only FAA-approved drone for flying over people in the U.S. Its operational capabilities, including a dual camera—RGB and multispectral, specifically the Duet M, were additional factors considered.
Pete Kelsey“You can fly a lot of drones, but not a lot of Operations Over People (OOP) approved drones. The eBee X was the right choice”.
Pete Kelsey
In Pete Kelsey’s assembled team, Bobby Valentine, a self-described technology evangelist, brought a wealth of expertise and was in charge of the eBee X mission.
Due to the tight schedule and the flight window, Valentine had only a limited frame of two days for aerial mapping. On the first day, he familiarized himself with the island’s obstacles that were not accurately represented in the flight plan, such as water towers, a lighthouse, and tall trees. The second day was designated for the flight, strategically planned to maintain a consistent altitude under 300 feet / 90 m AGL to avoid obstacles. Three visual observers were placed to address potential data connection issues due to the prison’s thick walls.
Bobby Valentine“The eBee X drone is solid—one of my most reliable workhorses”.
Bobby Valentine
In one flight, he gathered data for the island’s 27 acres / 10 hectares with the eBee X drone and its Duet M dual camera, simultaneously capturing RGB and multispectral information. “The eBee X worked seamlessly. The operation and software were great. I lost radio connection in three passes, but the drone reestablished connection and continued mapping flawlessly,” stated Bobby, showcasing the system’s reliability during operations.
Bobby Valentine“Your bird is truly amazing to watch in action. The entire team on the island was impressed with the flight and the data results of the Duet M camera”.
The team faced diverse challenges during the mapping, including navigating bird populations, coordinating with general aviation, and addressing complications due to the island’s topography:
Permit procurement: Getting the necessary permits for the project was time-consuming, spanning 9 months in total. As for the drone, the eBee X’s NDAA compliance and status as the sole drone approved by the FAA for Operations Over People in the U.S., without needing a waiver, provided them with a strategic advantage in navigating certain regulatory hurdles.
Alcatraz’s historic structures: The buildings of Alcatraz prison are deteriorating, and certain areas of the island, which are off-limits to visitors, pose a potential threat to their structural integrity due to hazardous conditions.
Navigating wildlife: Alcatraz’s protected birds and diverse fauna required careful coordination with National Park Service biologists. The eBee X’s silent operation played a pivotal role in maintaining a disturbance-free environment. Bobby highlighted, “The eBee X is beautiful to watch; it’s like watching a bird fly, and it doesn’t make a lot of noise, unlike the quadcopters.”
Operational challenges: The team had to contend with low-flying Coast Guard helicopters patrolling the San Francisco coast. However, coordinated efforts on the day of the eBee X mapping ensured a seamless operation.
Strategic landing maneuvers: Operating in Alcatraz’s unique topography presented challenges, particularly during the landings of the eBee X. Strategic planning was crucial, considering the deteriorating conditions of parade areas and outdated maps lacking updated structures and tall trees. Bobby Valentine had to navigate around a 40-foot-tall structure and execute steep landings near water. Learning from initial challenges, he recognized the importance of creating a Digital Surface Model (DSM) in the first flight, facilitating smoother landings in subsequent operations.
Pete Kelsey“The eBee X’s compliance and approval for flying in such sensitive areas demonstrated its suitability for the project and simplified the permit process”.
Multi-layered dataset for diverse applications: The project generated a unique dataset with various layers of information – photogrammetry, TLS, SLAM and drone-based LiDAR thanks to the diverse tools used. This output holds immense potential for diverse applications, from historical research to efficient park management and future development projects. The accurate data will also help the National Park Service in prioritizing essential fixes within Alcatraz’s historic structures.
Survey control and accuracy: The establishment of survey control was pivotal, ensuring alignment and meeting stringent level-of-detail requirements with an impressive 3 mm absolute accuracy across the dataset.
Efficient data capture and dual-sensor advantage: The eBee X showcased unparalleled efficiency capturing both RGB and multispectral data in a single flight with its Duet M camera. “This great advantage eliminates the need for multiple flights, a cost-saving feat when compared to other drones on the market” notes Bobby Valentine. The GSD came in at 2.29 cm / 0.90 in.
Collaborative excellence: The project’s excellence extends beyond mapping; it reflects collaborative efforts among tech giants who, in regular circumstances, might be considered competitors. The collaboration led to the successful completion of the project.
Daytime dataset completion: The eBee X’s data post-processing stood out as the first complete photogrammetry dataset obtained on the same mapping day. This not only impressed the Park Service personnel but also played a crucial role in winning their support and understanding.
Wildlife-friendly operations: On-site biologists appreciated the eBee X’s silent operation, emphasizing its minimal disturbance to nesting birds.
Temporal tracker: Alcatraz, amidst seismic activity, salt, and the sea, constantly undergoes transformations. The team, aware of these changes, created a digital twin of the prison, a “temporal tracker” aiding in understanding the pace and nature of these changes.
One opportunity: Operationally, the eBee X’s ease of use, reliability, and capability to obtain dual data in a single flight proved indispensable. With just one chance to capture the aerial information, Bobby Valentine relied on the eBee X as his trusted workhorse.
Technology making the invisible visible: The multispectral technology of the eBee X’s Duet M camera brings the once invisible into view, offering practical applications in revealing hidden historical insights, particularly in archaeology.
Data capture success: Pete proudly declares, “The Alcatraz mapping is complete, with no gaps or missing data identified, eliminating the need for additional capture. As of January 2024, we are deep into the post-processing stage, accumulating data up to 3 terabytes and still rising.”
Pete Kelsey“What’s so unique about this project is what the data can be used for ANYTHING”.
The comprehensive and one-of-a-kind dataset, with its versatile applications, stands as a monumental contribution to the preservation of Alcatraz. It ensures the historical legacy of this iconic site endures for generations to come.
Alcatraz Island, located 1.25 miles / 2.01 km offshore from San Francisco, California, has a rich history. Developed in the mid-19th century, it housed a lighthouse, military fortification, and later became the infamous Alcatraz Federal Penitentiary in 1934. Notable for imprisoning figures like Al Capone, the prison closed in 1963. Today, Alcatraz is a popular tourist attraction managed by the National Park Service. Acquired in 1972, the island features historical landmarks, including the oldest operating West Coast lighthouse.
Designated a National Historic Landmark in 1986, Alcatraz encompasses 22 acres / 8.9 ha and is home to diverse habitats, including cisterns, bluff crevices, cliff tops, tide pools, and parade grounds. These areas support various wildlife, such as seabirds, salamanders, and deer mice.
The island’s flora includes neglected gardens that are being restored after 40 years. Heirloom rose hybrids, believed to be extinct, were rediscovered, and the gardens now showcase a variety of roses, succulents, geraniums, and fruit trees. The preservation efforts aim to balance the restoration of historic gardens with the protection of bird habitats.
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