Drones are becoming a powerful tool within the mapping and surveying industry. They can effectively perform work for 3D mapping, land surveys, photogrammetry, and topographic surveying with increased efficiency by flying above the ground. This information is then used to help make critical decisions about the upkeep of infrastructure, construction site planning, and delineating property boundaries.
What is an Aerial Survey (Drone Survey)?
Put simply, a drone survey is an aerial survey conducted by a drone. Using sensors, such as RGB or multispectral cameras, or LiDAR payloads, drones can capture a vast quantity of data, quickly. Aerial surveys combine the sensors along with survey-grade ground points and aerial targets to accurately align the data to the ground.
By processing these images, photogrammetry software can then create map-quality images and 3D models, from which it can measure accurate distance, as well as surfaces and volumes of physical objects. Each aerial survey result is millions of points that form visual 3D models combining points and images together to gather the most accurate view of what is happening on the site.
Photogrammetry and LiDAR
Photogrammetry is the process of measuring from images, and its key purpose is digitizing reality for surveying and mapping. The captured overlapping images are processed to generate precise models of space. At McSteen, we generally use 70-90% overlap on our aerial survey to capture a high-grade of data that, in turn, allows for a higher accuracy of measurement.
LiDAR, on the other hand, is used for measuring distances based on laser light. It works by illuminating a target object or space with laser light and recording the time it takes the laser light to return to the sensor to measure distances with high accuracy.
While these two technologies can be used independently, there are benefits to using them together. When combined, LiDAR and photogrammetry bring more detail to a project that may not have been achieved by either individually. Pix4d Mapper is a software that combines all of the the data points from LiDar and photogrammetry to create the 3D models and point clouds, while PIX4Dsurvey allows our team to draw lines on top of the model, as necessary.
The Benefits of Using Drones in Mapping and Surveying
Drones are able to acquire data from vantage points that are not accessible to humans, especially those areas with challenging terrains. There is no need for human operators to measure points in hazardous locations physically, rather the drone is able to fly over an area, capturing the same amount of data in a shorter time frame.
Using drones for mapping and surveying offers the following advantages:
- Speed – Drones can scan acres of land in a fraction of the time it takes to manually survey on the ground, especially in areas of challenging terrain.
- Reduced Cost – A drone can capture data faster and safer, which may reduce costs.
- Reduced Operational Risks – The use of drones to capture topographical site data means that surveyors don’t necessarily need to be on-site or in dangerous areas to acquire data, making accessing it safer and easier, especially in hard-to-reach areas.
- Improved Quality of Data – Drones are constantly scanning and creating thousands of measurements, resulting in incredibly detailed and highly accurate point files within a few millimeters, when paired with traditional survey methods.
The Most Common Uses of Drones in Surveying and Mapping
Just as with traditional surveying, drone surveys have a wide range of applications. Typical land surveys establish boundaries, define lines, capture historical evidence, and create records for legal documents like deeds. Construction surveys determine where a highway, structure, or building will be located or define how land needs to be graded before construction begins.
- Base Mapping/Preliminary site assessment – Used to determine the most suitable land-use in terms of development and planning, or for construction purposes. It uses the drone to collect imagery and topographic relief of the land to give an idea of the current condition of the land, slope, and relief to better enable an architect or land developer to make decisions on its use.
- ALTA Surveys – Using a drone and a combination of software, including PIX 4D/PIX 4D Survey and AIRworks, drones can be used to defray the cost of large ALTA surveys if the project is a good candidate for drone imagery. The drone is able to fly the site and draw in many of the features on the parcel, reducing the need for the crew to manually measure all of the property improvements and significantly decreasing the number of man-hours required in CAD as well.
- Stockpile Monitoring – Traditional stockpile measuring methods that involved a surveyor needing to climb up a stockpile to generate data points with a GPS was time consuming, inaccurate, and expensive. Drone-based volume measurement, however, allows for substantially lower cost, faster and more accurate information in just a few clicks. A top-down angle view enables one to see every detail on the stockpile, allowing in turn, a much more accurate output.
With more than 50 years of experience in land surveying, throughout all 88 counties of Ohio, McSteen Land Surveyors is a leader in the industry. Contact us today and let our team of survey professionals take on your surveying needs, as well as draw inspections and utility locating.