Drones for Surveying
Drone survey means the use of drone or unmanned aerial vehicle to capture data. Drones are powerful commercial tools providing adapters with leap in efficiency and safety. Drones have ability to capture data from above, drone have been successfully introduced in surveying field to perform land surveys, photogrammetric, 3D mapping and topographic surveying. Basically surveying is an art, profession, technique and science for obtaining the three dimensional positions of points and the angle between them. Surveying with drone enables surveyors to perform survey of advance level. With the help of drone topographic survey is performed of same quality with high accuracy and less cost. After the invention of drones the cost of site surveys are reduced and accuracy is increased.
Natural resources and the condition of natural resources is the major concern of the world. One of the best methods to monitor natural resources is maps. The most common method for map and survey any particular area is terrestrial surveying. In terrestrial surveying distance between two points and angles are measured with the prism reflector and Total Station. Minimum two persons are needed to perform terrestrial surveys one person to handle the total station and other person to take prism to target position. In real conditions terrestrial survey can be effective by four persons or more. Terrestrial method is famous for surveying small narrow areas because it requires fewer instruments and less number of people and we can monitor change in natural phenomena within small area. Drones can be used to obtain high quality surface images at lower cost. Images take from drone can be turned into maps and it can be easy to monitor the natural phenomena. Unmanned aerial vehicle or Drone technologies are most efficient then terrestrial surveying because technology can minimize the time as well the cost. Drone can cover the distance of 15 km in 25 minutes and drone have better coverage of mapping then terrestrial survey. On other hand, terrestrial survey requires at least four persons to perform the survey. By conducting a topographic survey of park it take 135 minutes to cover 0.57 hectare. Terrestrial is survey is failed on coastal side because during high tide terrestrial survey cannot be performed because all lines are covered by water. It cost $250,000 for two year survey cycle. It means terrestrial survey is time consuming and expensive also challenging in remote areas. Drones can cover the difficult and dangerous areas because it’s an unmanned device and it fly far away from the operator so operator can be at safe place. Some areas which are difficult to access and monitoring of those areas are difficult and dangerous due their terrain. Drones are effective to monitor the complex topographical areas, dangerous area and Polar Regions. Drone not only gives us the variety of contour maps but all photographic maps and three dimensional maps and these maps will be combined with other data using GIS software. Drones can be a good tool for classification, obtaining 3D images and maps of coastal morphology. Drones are also used in coastal monitoring to identify erosion in coastal zones. Drone operating is not simple as we think because there many challenge to operate it. Ability to navigate the drone in unknown or urban terrain is very important because there are many obstacles in that can endanger the equipment. Drone system has a tool to be used in difficult terrain a good piloting skill is also necessary otherwise drone can hit anything or drop in a remote area that can damage the equipment. Strong thermal wind can cause difficulty for drone. Surveys are cancelled if the wind gusts are more than 40 km/h because strong winds can cause damage to drones. It is also suggested that not to use drone for surveys in high populated area due pedestrians and traffic. Trees and buildings also should be avoided during the survey it can cause damage to equipment. Another factor which can affect the drone is power supply and it can affect its range and endurance. Increasing battery system is not suitable due to its weight. Now a day’s wireless drones are used and energy transfer in drone is through electrical power transmission. In contrast terrestrial surveys are simple then drone surveys. Terrestrial survey can be conducted in complex terrain, in many environmental obstacles and highly populated. The main problem for terrestrial survey is only weather since the equipment are not water resistant.
Benefits of drone surveying
There are many benefits of drone surveying such as:
Reduce project time
For centuries surveys were tasked with walking to cover the land they surveyed and it is very demanding as time consuming as well. Just imagine walking a 200 acre land to find the property corners in order to make the topography of the land. Surveyors also deal with the vegetation that may exist on the property. Today, surveyors use drones to complete these tasks.
Increase Data Accuracy
Traditional photogrammetric is now allowed in open areas for image collection, which is then processed into measurable data. Light Detection and Ranging, or what is referred to as LiDAR can be utilized in areas containing dense vegetation. Originally developed in the 1960’s, LiDAR systems were too large and expensive for drone use, however new technology now allows placement on some larger drones. LiDAR drones facilitate land surveying in challenging environments where field crews were previously needed. LiDAR can also be used to measure power lines for sag, which is very difficult and time consuming by any other method. Drones will not replace the need to locate the property corners by hand, but they are beneficial in many other areas that are very labor intensive, which makes drones much more efficient.