Drone Mapping

With the advancement in technology day by day and application of these technologies in the field of engineering it has redefined the ways of engineering practices such as surveying, construction, engineering design and analysis. Among its advancement Drone Mapping is also one of the remarkable achievements.

Drone Mapping involves taking series of aerial photographs at certain altitude from the ground surface and later process them to get the stitched ortho-photomosaic of the survey area. The principle of drone mapping is completely based on photogrammetric surveying, where we maintain certain forward and side overlap (70-90 percent) between the consecutive images and later produce 3D data of the survey area using pixel match between those overlaps. To
maintain the accuracy of drone mapping, we often use Ground Control Points (GCPs). These points are those whose co-ordinates are already known to us and are generally provided by RTK GPS or Total Station. Accuracy of drone mapping is measured In terms of Ground Sampling Distance(GSD). The GSD depends upon the factors such as flight altitude, terrain type, weather condition, sunlight intensity.

With the use of drone technology in the field of engineering surveying and mapping it has saved both time and money. The pace with which the progress of the work is achieved using drone technology is no match for other methods of surveying. It can survey an area of 28.2 Hectares in just 13 minutes of flight time. In general Drone also referred as Unmanned Aerial Vehicle (UAV) consists of high resolution camera, sensors, GPS, battery and propellers that are mounted to the rotating motors. The propellers are responsible for flying the drones at the desired paths to take the aerial photographs.
Drone mapping not only involves the field work, it also needs some dedicated table work. Since the raw data itself will be heavy in file size and for stitching those individual images together based in pixel match we need to have powerful computer with processing software like pix4D, Drone Deploy and Agisoft PhotoScan. Processing of the raw data will be dependent on the project area and the configuration of the computer. After the data are processed we can get otho-photomosaic, contours, Digital Terrain Model (DTM), Digital Surface Model (DSM), and 3D model of the survey area. Some of the popular drone manufacturing companies are DJI, Parrot, Power Vision, 3DR.Similarly some of the established drone mapping service providers and cloud based processing providers are Sense Fly, Precision Hawk, Propeller Aero and Drone Deploy.

Drone technology has countless applications in the field of engineering. The most advantageous aspect of drone is that it can fly. It can reach even the places where it’s impossible to use other surveying methods and collects data that will be helpful for the engineers and designers. Some of the fields in which this technology is used are mining, quarry site, marshy lands, landslides, hydrological survey, road survey, airport survey and construction progress monitoring.

Rules and Regulations for Drone Operation in the Context of Nepal

One cannot simply take out and fly drones in Nepal. There are certain rules, regulations, paper works and flight permission from the concerned authority before you are all set for flying a drone. Civil Aviation Authority of Nepal (CAAN) has clearly stated about the requirements for the permission of drone flying in Nepal. Information like the model and type of drone, weight of drone, date, time and place of flight, drone pilot’s information are required to be filled up. Generally one needs to take permission from Ministry of Home Affairs and CAAN, and permission from other authorities depends upon the location of project area.

Drone Mapping Service Companies in Nepal

Application of drone technology for the purpose of mapping is introduced only by a handful companies in Nepal. Some names of the company that have taken a step to provide  such service are REAL NEPAL Engineering Solutions, NAXA, DroNepal, GeoSpatial Systems, Nepal Flying Labs.