What is aerial lidar surveying: Aerial lidar surveying combines traditional aerial photography and most recently, LiDAR data. These surveys involve an unmanned aircraft (drone) that carries various photographic and/or laser equipment which can be used to create 3D elevation models of the Earth’s surface.
The photo-side of lidar has been utilized for decades in large scale projects such as city planning and rail corridor mapping where accuracy is not critical but coverage area is. Lidar on its own has increased in popularity over the past few years because it gives a dense point cloud dataset which is key when wanting to capture more detailed information associated with terrain changes. A benefit of having a multi-sensor system is that individual sensors can be applied to smaller scale projects where accuracy and detail is required.
Aerial lidar surveys involve two components, a lidar sensor and an aerial survey platform such as a multirotor, airplane or helicopter. When planning an aerial lidar survey it is important to do your research on the best type of aerial vehicle for the job as certain sensors produce data that requires more power or weight lifting capabilities. For example LiDAR systems are normally heavier equipment because they require larger laser scanners which means greater lift capacity is needed – therefore fixed wing aircrafts are often used.
The combination of different types of sensors provides the most accurate results when covering large areas over hilly terrain – however this technology can also be very useful in mapping small areas that have dense vegetation or are otherwise difficult to access. Although LiDAR is often chosen for projects requiring the highest level of accuracy, aerial lidar surveys also produce quality results with excellent point densities.
As unmanned aerial vehicles become more affordable and accessible it makes sense to use these systems as an effective tool for collecting large amounts of data over a small amount of time. Although LiDAR technology is advancing rapidly, aerial lidar surveys still offer several advantages when compared to other types of automated data collection methods such as terrestrial Lidar (TLS). Aerial lidars can be used in any terrain – even where there are no roads or trails making them ideal for remote mapping missions. They are safer than manned aircrafts which gives surveyors the ability to fly at higher altitudes.
Another advantage is that aerial lidar surveys can be planned quickly which allows for changes in the schedule due to bad weather conditions unlike ground based LiDAR where you have to wait until it’s safe enough for a crew to traverse an area before gathering data. This means that projects with tight deadlines are not compromised by slow progress of field crews.
An interesting benefit of using unmanned aerial vehicles is that they can be flown in areas where it would otherwise difficult or too expensive to access – this includes steep terrain, dense vegetation and even areas lacking landing sites for manned aircrafts. Since aerial lidars do not require physical contact with the Earth’s surface, there is no damage incurred when collecting data over sensitive regions such as coastlines or national parks.
Although wide area lidar data can be acquired faster with aerial sensors, ground based lidar systems are still highly suitable for smaller projects where higher accuracies are required. Aerial survey platforms are extremely useful when collecting LiDAR data over larger areas because they generally have better coverage speeds than TLS which makes it easier to capture wider swathes of terrain in a short time frame. Since unmanned aerial vehicles are so accessible these days, costs associated with lidar surveys have come down significantly making them more affordable for development companies, researchers and inventors who want to gather 3D elevation models of geographical regions.
