For thousands of years, humans have developed and used different surveying tools and techniques to measure and map areas on Earth. From special ropes and chains documented in ancient history like the Rope Stretchers used in building the Great Pyramids of Egypt, The Roman Groma and Gunter’s Chain. With the advancement of industries, the need of measuring angles was satisfied with the modern Theodolite along with the Triangulation Method. Then, the Tellurometer or Microwave Electronic Distance Measurement was introduced to measure long distances. The Total Station was introduced in the 70s combining distance and angle measurement. In more recent developments, the Global Positioning System made up of a constellation of satellites uses the Triangulation method to accurately measure distance and angles between the satellite signal, a fixed base station and a second roving antenna allowing for Real Time Kinematic surveying.
Ground Vs Aerial Surveying
Today, the surviving surveying tools still being used are the Theodolite, Total Stations and GPS RTK with the latter being the most common. The GPS RTK had also seen great evolution with the advancement of aircrafts and cameras, the aircraft became the second roving antenna of the GPS system that documents the position of the images taken by the camera mounted on the aircraft. The images and their geo-location data are then processed through Photogrammetry software's to create many kinds of insightful datasets such as 2D OrthoMosaic Maps 3D Models, a method now known as Aerial Surveying and Mapping. And since you can mount different kinds of sensors to the aircraft, mapping with LiDAR, Multi-Spectral Sensors, FLIR Thermal Cameras and many other sensors were utilized to create specific maps for their respective industries. For example, mapping with LiDAR helps creates an accurate representation of the ground’s Topography regardless of vegetation.
In the past decade, the major advancements in aerial surveying and mapping mostly came from developments in Unmanned Aerial Vehicles (UAV) or Unmanned Aircraft Systems (UAS) such as DJI’s Matrice 300 RTK, shifting away from large and expensive Civil Aircraft for aerial surveying to smaller and much cheaper UAVs becoming a handy tool in the surveyor’s arsenal.
In contrary to what some might think, these tools and technological advancements are meant to aid and not replace the surveyor. One of the main advantages of Aerial Surveying by UAVs such as multi-rotor drones like the Matrice 300 RTK or Phantom 4 RTK is that they are very easy to pilot, thus it is simple for a surveyor to adapt to it whereas it is much more difficult to train pilots to produce topographic data. Nevertheless, surveyors don’t just collect data, they also interpret this data and contribute to the decision-making process. Neither will aerial surveying tools replace ground surveying tools like the Total Station and GPS, rather it is an extension to the toolset where each tool is relevant for specific situations. Total Stations or GPS systems will still be used for several tasks such as ground control points (GCPs) which serve as geo-referencing checkpoints to optimize data collected by UAV. Ground Surveying equipment will also be needed to physically mark excavation points on the ground for example. When it comes to mapping large areas though, quad-copter UAVs will be the most efficient tool. So instead of taking numerous, time and manpower consuming points to map a large area, a quick survey can be done by the DJI Matrice 300 RTK and map 2 square kilometers in less than 40 minutes. Yet, Aerial mapping data could be processed through many different softwares such as DJI’s Terra software for planning and reconstruction, yielding different kinds of usable maps such as contour line maps, topographic maps, color codes, Digital Surface Model, Digital Elevation Model 3D Models and PointClouds. Classification softwares are also utilizing AI capabilities to mark the different objects captured by different sensors. For example, running a classification software on images of a street captured by DJI’s Zenmuse P1 Photogrammetry Camera or DJI LiDAR Payload Zenmuse L1 would classify the road, the road markings, vegetation, bushes, trees, streetlights, power grid poles, cars, humans, pavement, trash bins and many more. Not only do the processing softwares classify objects but also detect certain deficits according to special criteriums, for example, using DJI Zenmuse H20T Payload with the 200x zoom capability and thermal camera overlay helps in inspecting and identifying a wide range of assets. The most important aspect of aerial surveying by drones like the M300 RTK, is the accurate replication of these surveys if needed, giving these softwares the ability to compare data captured in exactly the same manner but in different times giving way to progress monitoring and reporting.
In summary, on top of the incomparable advantage of aerial surveying which is collecting not only visual data that can be digitally reconstructed for easy analysis but also the ability to collect different kinds of data inputs as mentioned. Other advantages include the high precision and usability of collected data and collecting data from hazardous areas increasing the safety factor of surveyors by a hundred folds. All these advantages make it irresistible for surveying firms not to indulge in the benefits multi-rotor UAV like the Matrice 300 RTK.
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