Civilian drones are experiencing a real boom. But what are the benefits of drones in the field of urban planning and development? In particular, what are the reasons to choose drones for mapping and surveying? “The Truth About Drones in Mapping and Surveying”, a recently released white paper commissioned by BZ Media and written and produced by Skylogic Research, points out five appealing surveying and mapping applications.
Traditionally, data are collected by ground-based survey tools. But owing to low maintenance expenses, rapid deployment times and different types of installable cameras, drones can do the job faster, cheaper and safer compared with collecting data with satellites, manned aircraft, or road crews. Drones are suited for mapping road, highway, and railway infrastructures.
Five benefits of drones regarding mapping and surveying
1. Automated Mapping
With the support of control points like known coordinates or placed markers, the drone is able to fly autonomously a calculated fly path at a given altitude. Depending on the equipment, the drone can take common high-resolution color and infrared pictures. According to the published paper, it is recommended that each captured picture overlaps the previous image 80 percent to the front and 60 percent to the side. The data can be sent to the pilot during the flight or transmitted after landing.
2. Cadastral surveying
As an essential component of the legal creation of properties, licensed land surveyors can make use of drones to define property boundaries for purposes like renting, buying or selling buildings or land. A further benefit is the identification of boundaries and land features with drone-generated pictures. These information are the basis for the preparation of 2D like shown below. This way of mapping boundaries and property assets can have an essential impact on the real estate and appraisal industry owing to the low costs of data collection.
3. Corridor surveying
Drones are well-suited for capturing infrastructure facilities. For instance, drones are a basic working tool for the Mexican mapping and surveying company SKYLAB. They are mapping and capturing all kinds of infrastructure for the government, urban planners, etc. Photographs can be geometrically corrected afterward. They often contain inaccuracies as a result of topographic reliefs, lens distortions, and camera tilts.
4. Volumetric calculations
A further benefit of drones is the volume measurement of, for example, spoil heaps, stockpiles, or material extraction pits. After mapping the site with a drone, it is possible to generate a digital surface model (DSM). A ground-based surveying would be more dangerous and time-consuming. It seems quite outdated if a ground-based employee measures the stockpile elevation every 5 or 10 feet. According to VanZanten, owner of the mapping company SkyMedia Northwest, covering a 30-acre site with a drone takes around 30 minutes but a whole day for a ground-based surveyor.
5. LiDAR mapping
It is possible to create a virtual high-resolution map of the surrounding area with LIDAR. It creates a precise digital representation of objects, buildings, and the ground more detailed than common pictures. LiDAR is a surveying technology that measures distances by emitting beams of light in all directions from a laser source. It collects the reflected light with a sensor. By measuring the required time for a round trip of the laser light, distances can be calculated. A powerful computer creates a three-dimensional map in real time. According to the heavy LiDAR equipment, large drones are needed for aerial photographs.
Convince yourself of the benefits of drones and take a look at the award-winning urban landscape photography from Andy Yeung. In the end, it would not be surprising if more and more GIS professionals and scientists take advantages of drones.