In the realm of modern construction, the demand for accurate and efficient stockpile measurements has never been higher. Accurate volume calculations of stockpiles, whether of materials like gravel, sand, or construction debris, are crucial for optimizing project planning and resource allocation. Traditionally, such measurements required considerable time and resources using laser scanners or survey GPS equipment. However, with the advent of drone technology, construction professionals can now streamline the process and achieve precise measurements quickly and safely.
In this article, we will explore the benefits of using drones for stockpile measurements and the step-by-step process for calculating stockpile volumes (cut/fill) using drones
What are Stockpiles?
Stockpiles are accumulations of various materials, such as aggregates, construction waste, minerals, or other bulk materials, stored in specific locations on construction sites or in mining operations. These stockpiles serve as essential reservoirs of resources, making it imperative to monitor their volumes accurately.
Why are Stockpile Measurements Important?
In construction projects, knowing the exact quantity of materials in stockpiles is critical for several reasons:
1. Resource Management: Accurate stockpile measurements enable efficient allocation of resources, preventing shortages or excess material orders.
2. Cost Control: Precise calculations help avoid unnecessary expenses and improve budgeting accuracy.
3. Project Planning: Having reliable stockpile data aids in project planning, scheduling, and progress tracking.
4. Compliance and Reporting: Many construction projects require regulatory compliance regarding material usage, and accurate measurements assist in meeting these requirements.
Building up an understanding of the quantity of materials on site is really helpful for construction contractors to minimise the amount of mass moved around in the project.
By minimising the amount of ground movement, construction contractors can look at achieving significant cost savings by reducing logistics, materials and labor costs.
Why Use Drones for Stockpile Measurements?
Drones have revolutionized the way construction professionals approach stockpile measurements. Here's why they are preferred over traditional methods:
1. Speed and Efficiency
Drones can cover large areas quickly, drastically reducing the time required for data collection.
To give you some context, a 15 acre site would often take 2+ weeks to scan user a laser scanner, whereas it can be easily scanned with a drone using a single 20-40 min flight, making drones 100x faster in capturing millions of data points in one go.
2. Worker Safety
Drone-based measurements eliminate the need for workers to climb stockpiles or access potentially hazardous locations, promoting a safer working environment. It's 2023, and it's important that we invest in putting worker safety first. After all, people are the most valuable resources on any project!
Drone surveys are cost-effective compared to hiring survey teams or using laser scanning equipment. Depending on your geography, a drone survey can cost as little as $500-$1000 per survey or as low as $100-$200 per flight if you operate the drone yourselves. This compared with the time savings can yield high net savings for your business when the technology is applied across multiple sites in a standardised and scalable way.
Curious to learn more about the potential cost savings? Get in touch with us at email@example.com and we would be happy to walk you through a drone vs laser scanning cost model.
4. High Accuracy
Advanced drone technology, such as RTK GPS integration and photogrammetry, allow drone professionals to create highly accurate maps and models of the site, which can then be used for volume calculations. The overall accuracy of stockpile measurements depends on a variety of factors - the most important being GSD (Ground Sampling Distance) of the dataset. You can learn more about Ground Sampling Distance and how it affects the overall accuracy of your drone survey over here:
5. Frequency of Measurements
Last but not the least, due to the cost effective nature of a drone operation, it is now possible for in-house drone teams as well as service providers to conduct repeat surveys on a weekly / monthly basis, as required by the project and understand not just the quantities on a particular day but also how the quantities are changing over time.
This allows project managers and site managers to better forecast works and plan project schedules and logistics activities accordingly.
Creating 3D models of a construction site over time is becoming increasingly common, something we call 4D mapping. Here's more on 4D mapping and what it can bring to the construction contractors: Drone-Powered 4D Mapping in Construction
Calculating Stockpile Volumes (Cut/Fill) Using Drones
Now that we understand what stockpiles are and why measuring them is important, how does one actually go about measuring one using a drone?
The process of using drones for stockpile measurements can be broken down into the following steps:
Step 1: Flight Planning
Define the survey area, plan the flight path, and establish ground control points for accurate georeferencing. This step involves creating a flight plan (often a lawnmower or cross-hatch pattern) on top of your site using software platforms like Hammer Missions. This allows you to capture structured drone images which have a high degree of overlap between them.
Overlap between drone images is an important factor used to combine these images into a 3D model, which can then be used for volume measurements.
Another important factor is GSD, also known as Ground Sampling Distance. To learn more about GSD and how it affects the quality of the output data, please visit:
Step 2: Flight Execution
Deploy the drone to capture high-resolution aerial imagery of the stockpile area. This step involves connecting your drone to your flight planning app which then automatically flies the pre-programmed route with your drone and also automates the drone's camera so that it automatically takes images in the correct locations.
Step 3: Data Processing
Use specialized drone software like Hammer Missions to process the collected images and create a detailed 3D model. This step involves taking all the captured images from the drone's SD card and uploading them to a software platform which can then create 3D models from your captured data. These 3D models form the basis for the stockpile volume calculations.
Step 4: Volume Calculations
Once you have a high quality 3D model generated from the drone images, you can now use that model to perform volume calculations. These options are not supported by all 3D modelling software, so make sure you check that your software supports volume calculations before proceeding.
Calculating volumes can be as simple as marking a polygon over the stockpile and letting the software do the rest! You will typically see 2 different types of measurements:
1. Cut Volume: This volume represents the amount of ground above the surface.
2. Fill Volume: This volume represents the amount of ground below the surface.
Total Volume: This is typically calculated as Cut Volume - Fill Volume.
Overall, these measurements are very helpful to site engineers who need to track quantities of aggregates on site and plan logistics, labour and materials accordingly.
Once the measurements are available in the software, they can be easily copied out or the data can be exported to integrate with familiar CAD environments.
In conclusion, accurate stockpile volume calculations are vital for effective construction project management. Embracing drone technology for this purpose offers numerous advantages, including speed, safety, cost-effectiveness, and high accuracy. By following a structured process of flight planning, data collection, and image processing, construction professionals can harness the power of drones to streamline stockpile measurements. In this way, drones prove to be a valuable asset, not only saving time and resources but also ensuring efficient project execution and enhanced decision-making capabilities.
Hammer Missions is a software platform that helps drone (UAV) teams work with versatile & high-quality drone data for site surveys and asset inspections. Our goal is to help businesses cut costs and increase ROI by building operational efficiency in their drone programs.
Hammer Hub is a cloud-based platform where drone data can be processed and visualized in a full 4D environment.
If you haven't got a Hammer account yet and would like to try Hammer Missions you can get started with our free trial.
- Team at Hammer Missions