LIDAR SENSOR

Lidar, or light detection and ranging, is a remote sensor that uses light in the form of pulsed light to measure a variable distance. Combined with information collected by the airborne system, these pulsed lights produce precise 3D information about the target object.

LIDAR DRONE

It is a drone that carries a “lidar” sensor for the collection of data. The data collected from lidar-equipped drones can be used to make 3D models. The high accuracy and consistent results have made lidar drones popular. They have numerous applications in all different fields, namely archaeology, construction, mining, forestry, energy, power line inspection, and agriculture.

DRONE PHOTOGRAMMETRY

Drone photogrammetry is simply capturing large volumes of 2D images over a geographical area with different angles, which are later fed into specialized software that uses algorithms to reconstruct 3D topographical models and orthomosaic maps.

DRONE LIDAR VS PHOTOGRAMMETRY

With the recent developments in drone surveying, many myths and misconceptions have emerged regarding drone photogrammetry and lidar. There are as many differences as similarities between the two technologies. 

Both drone photogrammetry and lidar have their own sets of strengths and weaknesses. 

ADVANTAGES OF LIDAR DRONES

• Lidar technology does not require good lighting conditions to collect points. The energy emitted by the sensor itself, helps to capture points both during day as well as night.

• Lidar systems provide very high point density. Some commercial drones are even capable of generating 300 to 1,000 points per square metre. They are also capable of rebuilding fine elements such as cables and power lines.

• Each measured point generates more precise coordinates than the photogrammetric methods.

• The laser has a certain penetration capacity, with which it is possible to obtain digital models of different lands. The number of pulses that the sensor emits determines how many bounces it can detect in a particular direction.

ADVANTAGES OF DRONE PHOTOGRAMMETRY

The foremost advantage of photogrammetry is the ease and speed at which the data can be collected. With the use of UAV, photogrammetry can help in capturing images, analysing the data to get the measurements and convert them to 3D.

• Drone photogrammetry still remains one of the cheapest and most effective methods for aerial data collection.

• It offers a wide or broad view of the mapped area by utilising both topographic and cultural features of the land surface.

• Due to the fact that the information collected is permanent, it is much easier to re-survey or re-evaluate the site again to get any of the missing information without the loss of any time.

THE BETTER CHOICE

Lidar or photogrammetry? Which one’s better? Both technologies are doing well in their own fields. Choosing one of them entirely depends on the requirements for which they are used. For example, if accuracy is paramount, then lidar is the better choice. However, if cost is a concern, then photogrammetry may be the better option.

• Need to model terrain in densely forested areas? LIDAR is the winner. If these wooded areas appear as patches between which there is visible ground, photogrammetry is still a viable option.

• Do you need to capture a large area and time or cost is a critical factor?

• Is investment a limiting factor? If so, photogrammetry is a more competitive technology.

• Archaeology: Photogrammetry offers a unique opportunity to map an area using historic photos to understand the structures and layout on an archaeological site.

• Medicine: Close range Photogrammetry is used in diagnosis and treatment of certain illnesses and is widely used in biomedical research.

• Want a very low margin of error in locating each point or do you want the clouds to be extremely dense? Lidar is preferable.