Aerial photography using reconnaissance aircraft is not new. Annual aerial surveys of land development, crops, and waterways are maintained by local government agencies, and are a great help to environmental engineers and town planners. However, these aerial surveys are often low quality and cannot provide details of a single structure. The availability of low-cost drones equipped with high-quality cameras has changed all of that. Important applications of drone technology in the building industry include:

Property Maintenance: Maintenance is a major budget category for any building, particularly high-rise structures along the coast. A periodic, comprehensive survey to assess the structural health of a building is critical to perform timely repairs and develop an appropriate building budget. Unfortunately, structural surveys are traditionally conducted when the need for repair arises. These surveys are limited to roofs, balconies, decks, pools, and garages. Higher elevation areas are usually omitted due to lack of access.

Historic Records: Drones are well-suited for repeated flights along the same path (mission planning using recorded GPS coordinates). The advantage of this feature is that any structure can be viewed periodically to observe time-dependent changes such as concrete deterioration, roof wear and tear, hurricane damage, and modifications to surrounding structures. Images generated from repeated flights are particularly useful in insurance claims, especially after a major storm event.

‍Construction Records: The success of any construction project is tied to timely and accurately completing various phases of construction. Inspections, as-built documents, and progress payments are a big part of this process. Although humans can perform inspections, creating as-built drawings is time consuming. For a high-rise building, a drone flight mission of each story, prior to pouring the concrete, can capture all the reinforcement and post-tensioning layout in detail. Combining several closely-spaced photographs, one can create larger images that can be scaled to a structure’s CAD drawings.

Forensic Investigation: Replacing regular cameras on a drone with a thermal or infrared camera can be useful in determining water intrusion and crack locations. Infrared cameras are also valuable for assessing the health of crops.

‍3D Mapping: This feature is still in its infancy but promises to revolutionize the future of drone use. A fixed LIDAR (light detection and ranging) sensor is mounted on a tripod and moved inside or around a structure to capture a point cloud of data, which is then processed to generate 3D models. Recently, this technology helped in the reconstruction of France’s Notre Dame cathedral.

Indexing: Video recording is convenient but not very practical for capturing details. In any given video, one must watch the entire footage to pinpoint a location of interest. A single, high-quality photo is much better to capture details. Drones take many high-quality photos as they move in and around buildings at different altitudes. In a single mission, hundreds of photos may be captured for later use. However, organizing (indexing) these photos for easy access is still a daunting task.

Our locally-developed, proprietary software, Catalogger®, makes indexing a simple task, allowing users quick access to detailed views of areas of interest. The image with the blue markers shows a site that was photographed by a DJI Pro drone from various angles and elevations. The droplets represent locations where drone images were acquired. Once clicked, a user can view a 360-degree panorama of that location at different altitudes.

Although still gaining momentum, drone technology is already transforming the building industry. Today, drone surveys are a critical component in structural condition assessments. They provide a wealth of data that is easy to store, index, and access. That data, in the form of flight videos and still images, provides a historical record that can aid in insurance claims and future renovations. As drone use evolves, infrared and LIDAR technologies will be perfected, allowing even better management of residential, commercial, and industrial assets. "But what about manual surveys?" you ask. Like rotary phones, they will become a thing of the past.