A wide range of businesses around the world rely on land surveys to evaluate plots of land in great detail. From construction companies to civil engineers and cartographers to archaeologists, this process is essential for determining distances and angles between various points on land. 

Land surveying is a profession in which accuracy is key. The detailed maps, measurements and specifications that come from a land survey may be used to determine where roads, reservoirs or buildings will be constructed. Therefore, there is no room for error. 

Historically, land surveying in its traditional form, has been a very lengthy process and in some cases very risky. However, drones are transforming the way that surveyors work and survey land, allowing them to collect highly accurate measurements in a fraction of the time. 

How are drones used to survey land?  #

Using a process called drone mapping, a drone, otherwise known as an unmanned aerial vehicle (UAV) can be used to survey an area of land. 

There are various stages to conducting a drone survey. These include:

**Pre-flight preparation ** #

Following the project brief being set and an investigation of the land area conducted, the next preflight step is to check any local regulations where the survey is being planned. Drones must be permitted to fly in this location and other flight paths must be checked. Once you have confirmation on this and a date has been decided upon which to conduct the survey, the weather must be monitored closely. Rain, fog, snow or heavy winds will all disrupt the flight of the drone and affect the images taken. 

A flight plan for the survey can be created using the drone’s flight planning app. Tall objects and altitude differences must be accounted for within the flight plan. The drones battery should be fully charged and the drone camera memory card must have enough space to capture the entire project area. 

**Drone flight ** #

Drone surveying should only be carried out by highly skilled and fully trained drone pilots. The drone is controlled throughout the entire flight to ensure that the photography and/or videography is crystal clear and fit for use. 

During the flight, the drone uses downward-facing sensors to capture aerial data from the land below. These sensors can include RGB or multispectral cameras as well as LIDAR payloads. When using an RGB camera during a drone survey, the ground below is photographed multiple times and from various different angles. Each image taken is tagged with its own set of unique coordinates, so they can later be collated.

The higher the altitude that the drone flies, the more acres of land it can cover, but the lower it flies the more detailed the images can be. 

Data processing and outputs #

Using the downloaded data from the flight, mapping software is then used to create the required outputs to fit the brief’s requirements. 

Each of the images uploaded to the software contains information about physical information taken from the land for example distances and angles. By combining all the individual data together with the unique coordinates, the software can then create accurate maps and elevation models of the surveyed area.

What are the specific outputs that a drone survey can achieve?  #

Depending on what type of data sensors you use for your survey, as well as what surveying software you opt for, there are a number of outputs that are achievable. Each has its own specific use depending on the industry it is required for. 

These outputs include:

**2D Orthomosaic maps ** #

These maps are created by stitching together hundreds or thousands of digital photos that are captured by your drone survey. They provide a similar view to one you might see using a satellite view in Google Maps, only they are higher in resolution and have the ability to be updated as many times as you want. 

These 2D maps can help businesses to make rapid decisions using a real-world view that is an accurate representation of the earth’s geographic surface. They are especially important for the construction, infrastructure and environmental industries. 

**3D Orthomosaic maps and 3D models ** #

Using the images taken from your survey combined with additional oblique side images taken at 30° and 45 ° angles, the right software can also enable you to produce 3D maps or models. These models can be viewed from any side or orientation for in-detail inspection. These 3D structures can be compared to older versions to record change and calculate length, area, volume and elevation changes between two or more dates.

For land and mining industries, 2D photo-mosaics and 3D digital surface models are becoming a fundamental part of everyday operations. They allow teams to monitor progress and measure volumes of materials. These 3D models also allow for discrepancies between plans and reality to be identified quickly and easily.

In 2017, Japan was the first to use drone imagery coupled with powerful 3D models and earthmoving equipment to operate unmanned digging equipment on landfill sites.

**Thermal maps ** #

Drone surveying with a thermal camera can quickly identify areas below with abnormal heat signatures. 

Spot cracks, leaks and damaged areas can be detected in a matter of minutes with a thermal live map, thus minimising safety risks and reducing accidents. 

**LiDAR Point Cloud ** #

Point clouds are a collection of different points that combine to represent a 3D shape or feature. Each of the points has its own set of X, Y and Z coordinates and sometimes other attributes too. 

Using a LiDAR sensor mounted onto a drone, information can be collected to gain information about the shape of the earth and its features. LiDAR stands for Light Detection and Ranging. This technology sends laser pulses to the earth’s surface and once that laser returns back to the sensor, the system records the data that has been received. The output point clouds of the LiDAR collection method are saved in an .LAS file format.

What are the benefits of drone surveying compared to traditional methods?  #

As previously mentioned above, surveying land with a drone is much faster than traditional methods can allow, hence proving much more cost and time-efficient for businesses. 

Safety and risk minimisation are also huge benefits of drone surveying. Drones remove the necessity for human operators to physically gain access to measure areas that are high up, difficult to reach or hazardous. They also allow access to certain vantage points that are otherwise completely inaccessible to humans. 

Drone surveying can be beneficial to a wide range of industries and to survey a wide range of types of land. The land might be empty and ready for construction or it could contain buildings or thick vegetation, which the drones can easily manoeuvre around.  

In brief, drone surveying offers a modern alternative that is more flexible, quicker, safer and cheaper than other traditional alternatives. 

What are the best drones for surveying?  #

There are many drones on the marketplace that are suitable for surveying. Each drone has its own specific benefits, for example, some drones are designed to take off from difficult terrain, whereas others are specifically designed to cover long distances. 

We recently wrote about our top drones for surveying in 2021. So, if you are interested in utilising the potential of drone surveying technology for your business, then take a read to find out which UAV might be best for your needs. 

Want to find out more about drone surveying?  #

If you are looking to use drones for surveying or are thinking of upgrade your existing technology, then get in touch today and one of our UAV experts will help to answer all your questions and queries. 

We offer a range of business starter packages to suit anyone looking to train as a drone expert. It’s never been easier to access training and begin your drone journey than with Coptrz.

About the author: Bethany Jackson works in Digital Marketing for Coptrz. Coptrz are the UK’s number 1 drone experts. They provide impartial 360 drone solutions to organisations in order to increase productivity and safety whilst cutting costs.