The commercial drone market in India is expected to touch $885.7 million by 2021. There is a rising application of drones predominantly in sectors of mapping, surveying, precision agriculture, and cinematography.
Talking about drone surveys, they are a safer and quicker way to get more accurate data.
Why do you need drones for surveying?
Take for example the 7.8 magnitude earthquake in Nepal on April 25th 2015 that claimed about 9,000 lives and injured many. Doing manual search and rescue operations with blocked roads and piled up debris all around can take up several months. Moreover, there is a risk involved for the people going to do the operations. Here drones can prove to be a boon. Drones can be deployed to survey the affected areas and look for people.
Aerial survey maps can be very useful for geotechnical engineers, governments for town planning, mining companies and more.
Traditional land surveys are performed on foot with a team of surveyors with typical equipment like tripods, GPS, retroreflectors, etc.
Advantages of Drone Surveys
1. Safety: Drones are a safer way of surveying high-risk areas such as post-disaster scenarios, mountains, etc.
2. Cost-cutting: It is a cheaper alternative to manual and helicopter or plane surveys. It makes commercial projects more affordable.
3. Accurate results: Drones work closer to ground, enhancing precision, the data obtained can be used to make accurate 3D maps and simulations.
4. Time: Drone surveys take a lot lesser time. This will lead to faster completion of projects and lesser delays.
5. Ease of use: Drones are compact and easy to transport and set up. They also give flexibility to the user to perform multiple kinds of tasks.
Considering all the advantages, it is very clear why drones are increasingly being used in commercial projects and especially in construction projects.
How you can perform surveys using drones?
LiDAR (Light detection and ranging)
It is also called laser scanning. It is highly accurate and is used to obtain exceptionally detailed models of the surveyed area. A dynamic laser scanning device is used to construct a 3D point cloud using distances and angles measured by it. It can see through things and can provide precise images of what lies underneath. It is insensitive to light quality that means you can perform it even in darker areas.
Photogrammetry works on the principle of triangulation. In this method, the drone takes several pictures from different locations (lines of sight) with about 70%-80% of overlap. The lines of sight are mathematically intersected to produce point cloud. The point cloud can be used to make 3D mesh or digital elevation models using geospatial software.
Photogrammetry can generate colored 3D models and 2D maps, hence it is used in projects like construction inspection, asset management, and agriculture.