Table of Contents

• Why haul volume management is required

• Challenges of traditional volume management methods

• Volume management tools evolving with AI and IoT

• Accurately capturing site geometry with 3D point cloud measurement

• Automating volume calculations in the cloud

• Benefits of adoption

• On-site use cases

• Simple surveying with LRTK

• FAQ

Why haul volume management is required

On construction sites, accurately understanding “how much earth has been moved” through excavation and embankment is extremely important. For example, knowing the amount of spoil generated by excavation or the volume of fill enables accurate estimation of the number of dump trucks required and precise management of construction progress. Conversely, misjudging volumes can lead to schedule delays due to insufficient truck arrangements or increased disposal costs from excess spoil, potentially affecting the entire project. Accurate volume calculation is also indispensable for reporting to clients and for as-built management. Furthermore, tracking the amount and destination of hauled spoil is important to prevent improper dumping, and traceability management of volume data is required from environmental and legal perspectives. However, calculating and managing haul volumes on the spot has not been easy, and traditionally it has required a lot of time and effort.

Challenges of traditional volume management methods

Several methods have been used to determine volumes on site. One is using surveying instruments to measure ground surface heights, create cross-sections, and calculate volumes. This method requires a crew with surveying expertise and takes a long time from surveying to calculation and drawing. Because immediate results cannot be obtained on site, decisions during construction often had to be put on hold until volumes were confirmed. It was also difficult for anyone other than experienced personnel to perform accurate calculations, making the work prone to being person-dependent.

Another method estimated approximate volumes from the number of dump trucks and truck bed capacity. However, estimates based on visual judgment or experience lack precision and reliability. Irregularly shaped piles of soil or highly undulating terrain can yield large errors even if heights are measured at discrete points, because those points may not capture the overall shape. Transport records managed on paper or in Excel are also prone to input errors and delays in information transfer. Thus, traditional volume management had issues in both immediacy and accuracy.

Volume management tools evolving with AI and IoT

Recently, new volume management tools utilizing AI and IoT have appeared to address these issues. Advances in compact sensors and devices have made surveying tasks, which used to be large-scale, easy for anyone to perform. A representative example is the 3D surveying device that pairs with a smartphone—an ultra-compact surveying instrument that attaches to a phone. With devices that incorporate a high-precision RTK-GNSS receiver, an ordinary smartphone can quickly become a high-performance surveying instrument. Through dedicated apps, they can work with the phone’s camera or LiDAR sensor to capture site topography and soil volumes as digital data. There is no need to carry heavy tripods or stationary equipment; surveying and volume calculation can be completed with a palm-sized IoT device and a smartphone, which is revolutionary.

Furthermore, the use of cloud services and advanced algorithms is automating data analysis and sharing. Measurement data are sent to the cloud instantly via the Internet, and high-performance servers perform processes such as volume calculations in seconds. Complex calculations that were previously done manually are automated using AI-like methods, enabling anyone to obtain accurate volumes at the push of a button. Having data in the cloud also makes it easy to share information in real time with headquarters and other stakeholders, smoothing coordination between the site and the office. IoT sensors mounted on trucks have also enabled fleet management systems that automatically record vehicle location and load to digitize dump transport histories. This makes it possible to accurately grasp soil type, destination, and estimated volumes, ensuring traceability of spoil and helping prevent illegal dumping and enhance safety management. The adoption of these AI- and IoT-powered tools aligns with construction industry DX initiatives such as the Ministry of Land, Infrastructure, Transport and Tourism’s “i-Construction,” and they are becoming a new trend.

Accurately capturing site geometry with 3D point cloud measurement

One major feature of new volume management tools is the ability to digitize entire site topography using 3D point cloud measurement. Point cloud measurement is a method that measures a target’s surface as countless points using laser or photogrammetry and records them as a three-dimensional collection of points (point cloud data). Using this approach, there is no need to measure heights at selected locations as in traditional methods; an operator can simply walk around the site with a smartphone in hand to scan surrounding terrain, fills, and excavation areas in their entirety. A LiDAR-equipped smartphone can acquire hundreds of thousands of range points per second, and the high-precision GNSS in a small surveying device assigns accurate coordinates (latitude, longitude, elevation) to each point. As a result, the acquired point cloud data accurately reflect site geometry down to fine detail and include absolute position information. Complex terrain and large piles of soil can be captured in greater detail and in less time than manual surveying. For example, even an irregularly shaped spoil pile with varying height and slope can have its volume calculated with high accuracy once visualized as a point cloud. Subtle undulations that point surveys might miss are captured in the data, markedly improving the reliability of volume calculations.

Automating volume calculations in the cloud

Once point cloud data have been acquired, the next step is simply calculating the volume (commonly referred to as “earthwork volume” in construction). In the latest volume management tools, this volume calculation process is automated, allowing accurate volumes to be known instantly on site. Dedicated apps or cloud services analyze point cloud data and compute fill or excavation volumes in an instant. For example, for fill, the acquired point cloud can be analyzed to determine the height difference between the fill surface and the original ground surface, enabling immediate and accurate fill volume calculations on the spot. Tasks that previously required bringing surveying data back to the office to create drawings and apply volume formulas can now be completed on site via cloud processing. Because cloud-based high-performance servers handle the processing of large point cloud datasets, users get results quickly on their smartphones without worrying about heavy computation locally.

Cloud integration also makes data sharing easy. Measured volume data are saved to the cloud immediately and can be shared in real time with headquarters and subcontractors via the Internet. This not only reduces the time spent creating reports or sending emails after returning to the office, but also allows remote clients or supervisors to grasp the current situation in a timely manner. On cloud platforms, advanced analyses such as creating cross-sections from point clouds or measuring distances and areas can be performed in a browser. Without installing specialized CAD software on each PC, all stakeholders can view the same 3D data and numerical reports during discussions, enabling quick decisions without misunderstandings. The ability to obtain accurate volumes with one click is revolutionary for sites, and data utilization coupled with rapid information sharing dramatically improves overall construction efficiency and transparency.

Benefits of adoption

Adopting these AI- and IoT-based volume management tools brings various benefits to the site. The main advantages are summarized below.

• Immediate results and efficiency gains: Surveying to volume calculation could previously take days, but digital tools can deliver results the same day. Reduced waiting times speed up overall schedule management, and immediate cloud sharing of on-site data allows supervisors and stakeholders to confirm and decide quickly, speeding instructions and preventing rework.

• Labor savings and responses to workforce shortages: A single person can perform surveys with only a smartphone and a small device, eliminating the need to assign multiple staff to surveying. The construction industry faces serious labor shortages, but these tools enable efficient operations with fewer personnel. Allowing site staff to perform measurements without relying on seasoned surveyors helps build a system that is not dependent on specific individuals and reduces the burden of training younger staff.

• High accuracy and reliability: Centimeter-level positioning with RTK-GNSS combined with point cloud measurement yields very high accuracy for both positional and shape data. As a result, calculated volumes have errors constrained to a few centimeters, providing reliability far beyond traditional visual estimates or manual calculations. This enables data-driven as-built management and directly improves quality control.

• Improved safety: The number of times heavy tripods or surveying instruments must be set up in hazardous locations decreases, reducing worker burden. Measurements can be taken from safe, remote positions, lowering the risk associated with surveying on slopes, at heights, or on roads with heavy traffic. For example, tasks that previously required traffic controllers and long work times for road surveys can be replaced by quick smartphone surveys, reducing the time workers are exposed on the road.

• Data sharing and utilization: Because measurement results are stored as digital data, past volume data can be used as knowledge for estimating similar projects or planning construction. Sharing 3D data and numerical results online fosters common understanding with clients and other departments. Intuitive visualized data allow stakeholders who cannot visit the site to easily understand the situation, smoothing reporting tasks.

• Cost reduction: Improved surveying efficiency and labor savings significantly reduce personnel and equipment costs. Shorter interruptions for surveying reduce project duration, leading to indirect cost savings. Accurate quantity control permits precise ordering of materials and vehicles, reducing unnecessary expenses and waste.

On-site use cases

So, in what on-site situations are these advanced tools actually useful? Below are some representative examples.

• Verifying volumes of fills and backfilling: You can measure and record the volume of newly placed fill on the spot. By immediately comparing against design quantities, you can quickly see whether additional fill is needed or whether there is excess. Similarly, for backfilling, you can check on site whether the backfill has reached the required level.

• Managing excavation volumes: In excavation works, accurately managing the amount of excavated soil (spoil) is important. Using the latest tools, you can scan the terrain before and after excavation and compute the difference to accurately determine the removed volume. This enables precise estimation of required dump trucks and efficient scheduling of transport to disposal sites. Areas that were previously estimated from truck counts and bed capacity can be replaced by data-driven management, reducing uncertainty and waste while improving planning accuracy.

• Measuring spoil and material stockpiles: You can scan spoil or stockpiles of materials such as gravel and crushed stone stored temporarily on site and determine inventory accurately from their volumes. Regular measurements make it easy to monitor material depletion at a glance and avoid missing the timing for the next material order or spoil removal. Changes in quantity that are hard to capture by photos or visual inspection can be shown as numbers, improving inventory accuracy and enabling planned procurement and disposal.

• As-built management and reporting: If you obtain point cloud data of completed fill or developed terrain, you can use it for as-built management to verify whether construction was performed according to design. Overlaying the design model with current point cloud data allows you to color-code areas that are short or overfilled and calculate additional required earthwork. These visual checks can be shared immediately with supervisors or clients via the cloud, enabling remote stakeholders to intuitively understand site conditions. Using 3D models and color maps simplifies report preparation and explanations during inspections, leading to smooth handovers.

As shown, the latest volume management tools can be applied to many on-site tasks including volume calculations, significantly contributing to improved work efficiency and quality control.

Simple surveying with LRTK

One concrete example of a tool that easily realizes the above AI- and IoT-based volume calculations and 3D surveying is LRTK. LRTK is a device that contains a compact RTK-GNSS receiver that can be attached to a smartphone with one touch and is used in combination with a dedicated app. This turns an everyday smartphone into a high-precision surveying instrument, allowing anyone to easily start on-site surveying and volume calculations. Battery and antenna are built into a compact design, making it easy to handle. You do not need to transport and set up a total station weighing several kg; with LRTK, surveying is completed with a smartphone in hand.

With LRTK, a short training period is enough to start on-site surveying using point cloud measurement, and volumes of fills and excavation areas can be calculated immediately on site. Positioning accuracy is about horizontal 1–2 cm (0.4–0.8 in) and vertical 3 cm (1.2 in), achieving precision comparable to conventional professional surveying instruments. Acquired point cloud data can be uploaded to LRTK’s cloud service for analysis, and accurate volume results can be available within minutes after scanning on site. For example, even large volumes of soil exceeding 200 cubic meters can be grasped by simply walking the site with a smartphone when using LRTK. What used to be specialist-operated volume calculations with heavy machines and optical instruments are being transformed by LRTK into “simple surveying” that anyone can perform.

Moreover, LRTK is not limited to volume measurement; it also provides other on-site support features such as stakeout guidance and AR display of subsurface buried objects. It is attracting attention as a solution that truly promotes on-site DX (digital transformation) and dramatically improves construction efficiency and accuracy. Adoption is progressing rapidly at domestic construction sites, and it is expected to be a key advanced tool for promoting on-site DX. By actively adopting such cutting-edge technologies, on-site volume calculations and haul management can be carried out far more quickly and reliably than before. Consider adopting new technology to achieve smart site operations that balance productivity and safety.

FAQ

Q: Can I use the new volume management tools without special qualifications or surveying knowledge? A: Yes. If you can perform basic smartphone operations, you can use them without specialized knowledge. The dedicated app interfaces are intuitive and easy to understand, and surveying can be started with simple steps such as tapping the area you want to measure and beginning the scan. Complex settings and calculations are processed automatically in the background, enabling “simple surveying” that anyone can handle. In many actual sites, first-time users have been able to start using the tools immediately after a short explanation.

Q: Are there limitations on the range or distance that can be measured? A: It depends on the tool specification, but smartphone LiDAR sensors generally have an effective range of several tens of meters. For example, with LRTK, point cloud data can be captured for targets about 50–60 m (164.0–196.9 ft) away. If you want to capture a very large site at once, you can divide the area and scan multiple times, then merge the point clouds later. Basically, if a target is within visual range, it can be measured.

Q: How accurate are volume calculations? A: Volumes can be calculated with errors on the order of a few centimeters. The combination of high-precision RTK-GNSS positioning and dense point cloud data provides highly accurate terrain data for volume calculations, so the resulting volumes are extremely reliable compared to traditional manual estimates. However, accuracy may be slightly affected by measurement environment factors (for example, positioning accuracy can be reduced in areas with tall buildings or dense trees).

Q: How long does measurement and volume calculation take? A: It depends on the measurement area, but for small fills the entire process can be completed in a few minutes. For example, for a fill of several tens of meters square, you can finish scanning in under five minutes while walking with a smartphone, and cloud point cloud processing also completes in a few minutes. Being able to confirm accurate volume results immediately on site represents a dramatic time savings compared to the full day previously required for data organization and calculation.

Q: What advantages does ground surveying with a smartphone + IoT device have over drone surveying? A: Ground surveying with a smartphone and IoT device is superior in ease of use and immediacy compared with drone surveying. Drones have the advantage of capturing wide areas from the air at once, but they are constrained by weather and flight permission requirements, and generating point clouds from photos and calculating volumes can take time. In Japan, drone flights may also require qualifications or permits in some cases. In contrast, tools like a smartphone and LRTK can typically measure immediately on site in fair weather and even in mild wind or light rain, with cloud processing completing data quickly. The speed of being able to check results on the spot and the simplicity of operation are major advantages.

Q: How are survey data stored and utilized? A: Acquired data are securely stored in the cloud and can be viewed or downloaded as needed. Point cloud data and measurement results can be reviewed in dedicated cloud services as 3D views and numerical reports, and links can be issued for sharing with stakeholders. Data can also be exported as CSV or drawing files (such as DXF) for use in other software. Accumulated cloud data have high secondary value, such as serving as reference materials for future similar projects or for analyzing long-term changes.

Q: Can measurements be taken in rain or at night? A: Generally yes, but environmental precautions are necessary. LiDAR-based distance measurement works in dark conditions, so surveying at night is possible, but if photogrammetry using the smartphone camera is also used, lighting will be required. Light rain generally does not interfere with operation, but water droplets on sensors or lenses can affect accuracy. It is advisable to take measures to prevent equipment from getting wet and avoid extremely poor visibility conditions.

Q: Which smartphones can be used? A: Most recent smartphones can be used without issue. A dedicated small device is attached for use, and both iOS and Android are supported so you can use your existing phone. While LiDAR-equipped models are preferable for denser 3D scans, devices without LiDAR can still generate point clouds using photogrammetry (creating point clouds from multiple images). Supported OS versions and required specifications vary by tool, but in general, common smartphones can be used effectively as volume management tools.