DRONE SERVICES

Aerial Photogrammetry

Photogrammetry is a multidisciplinary field that combines the art, science, and technology of obtaining information about physical objects and the environment through the use of photographs. It involves the recording, measuring, and interpretation of visual features captured in photographic images to derive reliable data.

In essence, photogrammetry is a three-dimensional coordinate measuring technique that leverages overlapping photographs to determine the positions of objects. By taking photographs from at least two different angles, lines of sight can be computed and mathematically intersected to generate the 3D coordinates of the objects of interest.

Using specialized photogrammetric software, these objects can be transformed into accurate 2D and 3D models. Drones are commonly used in aerial photogrammetry to capture visual and positional data for site analysis and evaluation. Their ability to fly at low altitudes and provide high-resolution snapshots of a site make them ideal for aerial surveying.

The main output from aerial photography includes video, orthorectified imagery, and DSM models. The DSM model, in particular, is a comprehensive representation of the surface, including both natural and man-made features such as buildings, trees, powerlines, and more. Additionally, aerial photography can provide detailed mapping of existing property improvements and utilities, as well as DSM contours.

Note: a DSM is the most general form of surface model that includes all acquired points, representing natural and man-made features. A DSM includes the tops of buildings, trees, powerlines and other objects. In essence, it is a canopy model, and only sees the ground when nothing else is above it.

Aerial LiDAR

Aerial LiDAR: An Overview with Considerations

LiDAR, which stands for light detection and ranging or laser imaging, detection, and ranging, is a powerful tool for capturing 3D data. In the case of airborne LiDAR, a laser scanner is attached to an aircraft to create a point cloud model of the landscape during flight. This method is widely recognized as the most accurate and detailed way of generating digital elevation models (DTMs) for hard and bare surfaces.

However, it is important to note that LiDAR results can be variable in accuracy on vegetated terrain, despite being the most cost-effective method for surveying such areas. The accuracy of the results may vary from the specifications due to the challenges posed by vegetation.

One of the key benefits of LiDAR over photogrammetry is its ability to filter out reflections from vegetation, allowing for the creation of a digital terrain model that accurately represents the underlying ground surfaces, such as rivers, paths, and cultural heritage sites.

LiDAR technology generates a vast amount of data, with the ability to scan 2 million points per second. To make this data useful, it must be processed and relevant information extracted, typically by stringing or thinning the point-cloud dataset. Our in-house software tools are capable of removing unnecessary points without altering the integrity of the terrain shape, making the data usable for civil infrastructure design and quantity determination.

We are equipped to handle large LAZ format point-clouds, and can confirm the impact of thinning the dataset on the volume of data. The final product will be delivered to the client based on their preferences, such as tiles or ordered by chainage.