Instantaneous Point Cloud Earthwork Volume Calculation via Cloud Processing: Achieving On-site DX and Shorter Construction Periods with LRTK

Table of Contents

• Introduction

• Benefits and High-Precision of Point Cloud Volume Calculation

• Methods and Challenges for Acquiring Point Cloud Data

• Instant Volume Calculation via Cloud Processing

• On-site DX Progressing through Data Sharing and Visualization

• Construction Period Shortening Enabled by Real-Time Volume Management

• Easy High-Precision Surveying with Smartphone × GNSS (LRTK)

• Conclusion

• FAQ

Introduction

Earthwork volume calculation (estimating the amount of soil involved in excavation and embankment) is an indispensable and important process in construction and land development project management. Traditionally, the common method was to survey the ground before and after construction, create cross-section drawings, and calculate volumes using methods such as the average-end-area method. However, because this approach relies heavily on manual work, it requires considerable labor and time, and as the site area increases, variations in accuracy and workload become problematic. In recent years, attention has turned to calculating volumes using 3D point cloud data. By scanning the site to obtain a massive point cloud (a collection of points), building a terrain model, and directly measuring volume, you can understand earthwork quantities more quickly and with higher accuracy than before. This article explains the latest methods for making “point cloud earthwork volume calculation” instantaneous through cloud technology and introduces the potential for construction management innovation and shortening construction periods through digital transformation (DX).

Benefits and High-Precision of Point Cloud Volume Calculation

There are many advantages to using point clouds for earthwork volume calculation that traditional methods do not offer. The greatest benefit is improved measurement accuracy. Point cloud data records countless points that capture even minute surface irregularities, allowing terrain to be reproduced almost exactly. For example, in excavation work, by comparing the pre-construction ground point cloud with the post-excavation ground point cloud, you can directly calculate the volume of removed soil (excavated volume). There is no need to interpolate between limited survey points as in cross-section methods, enabling accurate quantity calculation that fully reflects terrain undulations. Also, once a point cloud has been acquired, you can calculate volumes “as many times as needed” by changing the calculation area or reference surface afterward. Because you can re-calculate or simulate under different conditions without additional surveying, point clouds offer flexibility for predictive simulations. For these reasons, point cloud–based volume calculation excels in both accuracy and efficiency, and is becoming the new standard for construction management.

That said, ensuring the quality of the point cloud data itself is crucial for high-precision volume calculation. Achieving a sufficiently dense, complete point cloud, ensuring survey points’ coordinates accurately match the reference coordinate system, and properly removing or processing unwanted objects such as heavy machinery and trees will enable low-error earthwork calculations. In practice, there are field reports showing that as-built quantities derived from point clouds (as-built = post-construction shape) fell within an error of about 1% compared to values obtained by traditional manual surveying; when conditions are met, point cloud–based volume calculation demonstrates reliable accuracy. Because point cloud volume calculation can reconcile accuracy and efficiency, it is truly a foundational technology supporting on-site digitalization.

Methods and Challenges for Acquiring Point Cloud Data

While the usefulness of point cloud data has become recognized, the on-site challenge has been “how to easily acquire high-quality point clouds.” In the past, it was necessary to use specialized equipment such as terrestrial 3D laser scanners or surveying drones and to perform measurements with a team including surveyors. However, with recent advances and the spread of photogrammetry technology, more construction managers and on-site staff themselves are obtaining point cloud data using smartphones or drones. Photogrammetry is a technique that reconstructs an object’s 3D shape from many photographs taken by a camera and converts it into a point cloud. Drone aerial photography can capture broad areas from the air in a short time, enabling surveying of large-elevation terrains or dangerous slopes without personnel entering them. Even with smartphone photography, if you take a sufficient number of photos from various angles, dedicated software can generate a high-density point cloud model. The ability to create point clouds with familiar cameras without costly laser scanners is a major advantage for advancing on-site DX and has attracted attention across the industry.

However, point cloud acquisition via photogrammetry has several challenges. First, accuracy is easily affected by shooting conditions. If photo resolution or exposure is insufficient, or if strong shadows or reflections are present on the subject, errors or missing data are likely to occur during point cloud generation. Also, even if you intend to scan only the ground surface, extraneous objects such as vegetation, heavy equipment, and debris may be captured, increasing the effort needed to extract the ground later. A more significant issue is that data processing can take a long time. While the photography itself may finish in minutes to a dozen minutes, subsequent photo analysis (point cloud generation) can take hours on a high-performance PC or via online services. With conventional methods, there is a time lag from surveying → data processing → volume calculation, and it is difficult to obtain results in real time on-site.

Other operational hurdles include the requirement for flight permission and piloting skills under aviation law to operate drones, and the risk that models generated from smartphone-only photogrammetry may be misaligned with real-world coordinate systems due to GPS errors. Even if you can create point clouds with a smartphone, they are unusable for as-built quantity calculation if their elevation and position are unclear. To guarantee accuracy, an extra step is often required to install calibration points (known-coordinate targets) and align them with the point cloud. Thus, although the potential for on-site point cloud acquisition has increased, several challenges remained for realizing the ideal of “anyone easily completing high-precision point cloud measurement on-site” using only conventional technologies.

Instant Volume Calculation via Cloud Processing

Cloud processing technology is the key to solving these problems and enabling completion of point cloud earthwork volume calculation on-site. Processes that require time and computing resources, such as photo analysis and volume computation, can be executed quickly using powerful servers in the cloud. Large amounts of photos taken on-site can be uploaded immediately over the network, and if the cloud performs rapid point cloud generation and volume calculation, earthwork calculations that used to take half a day to several days can be completed “within the same day.” For example, there are reports of sites where drone aerial photography of about 15 minutes was followed by cloud processing that produced an as-built point cloud model and completed volume calculations on the same day. This enables real-time quantity management, such as immediately checking the as-built volume right after heavy-equipment work is finished.

Results obtained via cloud processing can be shared instantly over the internet, eliminating the need to return to the office for data aggregation. Field staff can view cloud computation results immediately from a tablet or PC on-site and perform additional shooting or re-calculation as needed. If the cloud service hosts and visualizes point cloud data, you can display 3D models and verify volumes in a browser without having specialist software on hand. With on-site instantaneous volume calculation, if excavation is insufficient compared to the plan, you can immediately decide additional excavation areas; if embankment exceeds the design, you can quickly plan surplus soil removal—enabling rapid decisions without interrupting work. By leveraging the cloud, point cloud volume calculation has for the first time entered the “real-time” realm and is poised to significantly change construction management.

On-site DX Progressing through Data Sharing and Visualization

The advantages of handling point cloud data in the cloud are not limited to speed. Visualizing and sharing high-precision 3D data accelerates on-site DX. Uploaded point cloud models can be easily shared among stakeholders, allowing remote offices and clients (such as municipal officials) to check the site’s 3D status in a browser. Whereas as-built explanations were traditionally done by pasting plan or cross-section drawings into reports, point cloud data enables “interactive site reproduction” during explanations. For example, in a cloud viewer you can freely rotate and zoom the point cloud model of the measurement area, display arbitrary cross-sections on the spot, or show deviation from the design as a color-coded heat map with one click. This kind of visual information makes it easier not only for site supervisors and construction managers but also for clients and subcontractors to intuitively grasp the situation, reducing the time required for explanation and discussion.

Point cloud data utilization also contributes to more efficient report and form generation. Cloud systems can automatically aggregate volume calculation results, immediately outputting embankment and excavation volumes, and easily provide screenshots of the 3D models and comparison diagrams that serve as evidence. Attaching these images and numbers to as-built management materials produces highly persuasive reports. You can reduce time spent manually drafting drawings or pasting photos and directly repurpose digital data in reports—an advantage unique to DX. Recently attracting attention is AR (augmented reality) integration with point cloud data. By overlaying captured point cloud models or design 3D data onto the real-world view through a tablet or smartphone camera, you can intuitively perform as-built inspections and construction checks. For example, if you hold a tablet over an embankment under construction and overlay the design model with the current terrain point cloud color-coded, you can instantly see where and by how many centimeters you need to cut or fill. AR visual assistance helps prevent mistakes while fully leveraging precise point cloud data in on-site tasks; this approach is highly anticipated as the next stage of on-site DX.

Construction Period Shortening Enabled by Real-Time Volume Management

Introducing point cloud volume measurement and cloud instantaneous processing directly leads to shortening the overall construction period. Traditionally, calculating earthwork volumes by manual surveying required many steps, and on large sites a surveying team might take several days to a week to measure as-built, create drawings, and calculate volumes. In one development site, it was reported that four people spent a full week (a total of 20–30 person-days) on surveying from ground measurement to cross-section creation and volume calculation. Switching to photogrammetry and point cloud processing made it possible to complete the same work with two people in one day (2 person-days). This was possible because a drone captured dozens of photos from the air and the cloud performed point cloud generation and volume calculation that same day. In this way, point cloud utilization dramatically reduces the personnel and time required for surveying. Freed personnel can be allocated to other tasks, improving overall productivity.

Being able to measure as-built quickly also shortens the entire construction cycle. In the past, you often could not proceed to the next stage until surveying results were available, but if you can obtain volume data almost in real time, you can check differences between as-built and design on the spot and immediately take action. Regular point cloud surveys allow you to quantify daily earthwork progress, enabling objective weekly or monthly evaluations and early countermeasures when necessary. For example, if you perform drone aerial photography at the end of each week and save the point cloud model, you can graph weekly embankment volume increases or visualize where and how much soil was added since the previous week using color-coded maps. This kind of time-series volume management makes it easy to take preemptive measures such as increasing heavy equipment to address schedule delays, accelerating the PDCA cycle for construction management. As a result, projects can be completed with schedule leeway or, in some cases, the schedule itself can be shortened. Combining point cloud volume calculation with cloud instantaneous processing yields not only surveying efficiency gains but also significant time savings and productivity improvements across the site.

Easy High-Precision Surveying with Smartphone × GNSS (LRTK)

LRTK is a solution that makes the instantaneous use of point cloud volume calculation accessible to everyone. LRTK (L R T K) is a modern system that attaches a palm-sized high-precision GNSS receiver (RTK-GNSS) to a smartphone and allows point cloud measurement via photo capture or LiDAR scanning using a dedicated app. This enables centimeter-level 3D surveying (cm level accuracy, half-inch accuracy) that once required expensive surveying instruments to be performed easily with an everyday smartphone. If a field worker walks around a development site scanning with a smartphone in hand, a high-precision 3D model with position coordinates can be generated on the spot, allowing direct measurement of terrain volume and distances in the field. Since acquired data can be synchronized to the cloud immediately, you can calculate earthwork volumes in real time and make construction decisions without returning to the office. Tasks that previously took several days by outsourcing to specialized surveyors can be completed quickly by in-house staff, making LRTK a powerful DX tool even for small and medium-sized construction companies and sites.

Moreover, mobile measurement devices like LRTK have a strong affinity with AR technology, and their evolution into future construction support tools is expected. Displaying LRTK-acquired point cloud data or design 3D models overlaid on a smartphone or tablet screen enables more intuitive as-built checks and layout marking on-site. In practice, LRTK apps allow uploaded point clouds to be checked from office PCs and enable on-site functions that overlay design data and scanned point clouds on a tablet. For example, in slope work, overlaying the design slope model with the current point cloud in AR allows you to check surface irregularities and identify necessary touch-up locations on the spot. The fusion of smartphone RTK devices with point cloud and AR technologies has the potential to elevate site management to the next stage. As more user-friendly measurement technologies spread, an era will come when anyone—not just construction managers or surveying professionals—can routinely handle 3D data.

Conclusion

Efforts to make earthwork volume calculation from point cloud data instantaneous via cloud processing significantly contribute to on-site digital transformation (DX) and productivity improvement. Earthwork management that once required considerable time and effort can now be performed more quickly, accurately, and safely by leveraging familiar tools such as smartphones and drones together with the cloud. Regardless of role—construction manager, surveyor, municipal official, or ICT promoter—the common benefit is the ability to fully grasp site conditions with data and make prompt decisions. Solutions like the LRTK series support high-precision positioning and point cloud processing on construction, civil engineering, and surveying sites, enabling shorter work times and dramatic productivity gains. LRTK also complies with the Ministry of Land, Infrastructure, Transport and Tourism’s i-Construction initiative and is one of the optimal platforms to promote industry-wide digitalization. For details, please also see the [LRTK official site](https://www.lrtk.lefixea.com/). For product questions or implementation consultations, feel free to contact us via the [contact form](https://www.lrtk.lefixea.com/contact). Use the latest technologies for smart as-built management and take your site to the next stage.

FAQ

Q1. How accurate is earthwork volume calculation using point clouds? A1. If measurement conditions are met, combining drone photogrammetry with RTK-GNSS positioning can achieve accuracy on the order of several centimeters (a few in). Field cases report volumes calculated from photogrammetry-derived point clouds falling within ±1–2% of traditional surveying calculations. Using expensive laser scanners can achieve millimeter-level accuracy (0.04 in), but for typical earthwork as-built volume management, photogrammetry plus high-precision GNSS is sufficiently practical.

Q2. Is a drone required to acquire point cloud data? A2. Not necessarily. Drone aerial photography is effective for large sites because it can capture wide areas quickly, but for narrow sites or localized measurements, point clouds can be generated from photos taken with a smartphone or handheld camera. Recently, solutions that combine a smartphone with a small GNSS unit to perform easy high-precision point cloud measurement (e.g., LRTK) have also appeared. Choose the optimal measurement method according to the site scale and conditions.

Q3. Can point cloud data obtained by photogrammetry be used for official as-built inspections? A3. Yes. As part of “i-Construction,” the Ministry of Land, Infrastructure, Transport and Tourism has provided trial procedures for as-built management using UAV photogrammetry, and photogrammetry point cloud data can be used to calculate as-built quantities if certain accuracy confirmation procedures are met. Specifically, the procedure requires measuring accuracy using check points set before and after shooting and confirming that height-direction errors fall within the prescribed range (e.g., within 5 cm (2.0 in)). Currently, regional development bureaus and municipalities are beginning to operate according to these guidelines, so check the latest procedures before use.

Q4. What is the difference between photogrammetry and 3D laser scanners? A4. Photogrammetry’s advantages are low equipment cost and the ease of measuring wide areas at once. Because it generates models from color photos, the resulting 3D models are easy to interpret visually. However, accuracy can be affected by shooting conditions and the subject’s surface characteristics, and it may not reproduce well at night or on featureless terrain. Photo data processing also takes time. On the other hand, 3D laser scanners require higher initial investment but offer stable, high-precision measurement and can acquire data even in dark conditions or under some vegetation. Conversely, they struggle with targets like glass or water surfaces where lasers reflect or transmit. Overall, photogrammetry excels in “speed and ease,” while laser scanning excels in “accuracy and versatility.” It is ideal to choose or combine them according to site conditions and required accuracy.

Q5. Can point cloud earthwork calculation be done without special software or expertise? A5. Recently, more user-friendly point cloud processing software and cloud services have emerged, and it is becoming possible to semi-automatically calculate volumes without specialized skills. Some drone manufacturers’ analysis software and construction-oriented 3D volume calculation tools allow you to upload photo data and automatically perform point cloud generation and volume calculation. However, although these tools are becoming easier to use, accuracy management in measurement procedures remains important. Following shooting guidelines and checking for obviously unnatural areas in generated results, as well as maintaining basic surveying knowledge and data-checking habits, will increase confidence in the results.