Table of Contents

• Introduction

• Benefits and High-Precision of Point Cloud Volume Calculation

• Methods and Challenges for Acquiring Point Cloud Data

• Immediate Volume Calculation via Cloud Processing

• On-Site DX Accelerated by Data Sharing and Visualization

• Schedule Reduction Achieved by Real-Time Volume Management

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

• Conclusion

• FAQ

Introduction

Calculating earthwork volumes (the amount of soil and sediment involved in excavation and embankment) is an essential process in construction and land development project management. Traditionally, the common method was to survey the ground before and after works, create cross-sectional drawings, and compute volumes using the average-end-area method or similar techniques. Because these methods are largely manual, they require significant effort and time, and accuracy and workload issues increase as sites grow larger. Recently, using 3D point cloud data for volume calculation has attracted attention. By scanning a site to obtain vast point clouds (collections of points), building a terrain model from them, and directly measuring volumes, it becomes possible to grasp earthwork quantities more quickly and with higher accuracy than conventional methods. This article explains the latest approaches to making this “point cloud volume calculation” instantaneous through cloud technology, and introduces how promoting digital transformation (DX) on-site can revolutionize construction management and shorten schedules.

Benefits and High-Precision of Point Cloud Volume Calculation

Volume calculation using point clouds offers many advantages that traditional methods lack. The greatest benefit is improved measurement accuracy. Because point cloud data record countless points, including minute surface irregularities, they can reproduce terrain almost exactly. For example, in excavation works, by comparing the pre-construction ground point cloud and the post-excavation ground point cloud, the volume of removed material (excavation volume) can be directly calculated. There is no need to interpolate between limited survey points as with cross-section methods, enabling accurate quantity calculations that fully reflect terrain undulations. In addition, once point cloud data are acquired, you can compute volumes repeatedly by changing the calculation area or reference surface afterward. This allows flexible re-calculation or simulation under different conditions without additional surveying. For these reasons, point cloud-based volume calculation excels in both accuracy and efficiency and is becoming a new standard for construction management.

That said, ensuring high-precision volume calculations requires securing the quality of the point cloud data themselves. Obtaining dense, complete point clouds without missing areas; ensuring survey point coordinates accurately match the reference coordinate system; and appropriately removing or processing point clouds of unwanted objects such as machinery or trees—thorough attention to these aspects enables volume calculations with small errors. There are field reports showing that as-built quantities (as-built = the post-construction shape) calculated from point clouds were within about 1% error compared to values obtained by traditional manual surveying, indicating that point cloud volume calculation can achieve reliable accuracy when conditions are met. Thus, point cloud volume calculation, which balances accuracy and efficiency, 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, measurements required specialized equipment such as terrestrial 3D laser scanners or surveying drones and a team including surveyors. However, with recent advances and the spread of photogrammetry technology, more construction managers and site staff are obtaining point cloud data using smartphones or drones themselves. Photogrammetry is a technique that reconstructs a 3D shape from many photographs and converts it into a point cloud. Drone aerial photography can capture large areas from above in a short time, enabling surveying of steep terrain or hazardous slopes without sending personnel into dangerous areas. With smartphone photography, taking a sufficient number of photos from various angles can generate high-density point cloud models using dedicated software. Being able to generate point clouds with familiar cameras instead of expensive laser scanners is a major advantage for advancing on-site DX and has received attention in many places.

However, photogrammetry-based point cloud acquisition has several challenges. First, accuracy is easily affected by shooting conditions. If photo resolution or exposure is insufficient, or if strong shadows or reflections appear on the subject, errors or gaps can occur during point cloud generation. Also, even if the ground surface is intended to be scanned, the presence of vegetation, machinery, or debris in images increases the effort to extract only the ground later. A larger issue is that data processing can take time. Although shooting itself may take only several minutes to tens of minutes, photo analysis (point cloud generation) can take hours on a high-performance PC or online service. With traditional workflows, there is a time lag from surveying → data processing → volume calculation, making it difficult to obtain results in real time on site.

Other operational hurdles include the need for flight permission applications and piloting skills under aviation law to fly drones, and the possibility that models generated by smartphone-only photogrammetry may be offset from real-world coordinate systems due to GPS errors. Even if you can make point clouds with a smartphone, they are unusable for as-built quantity calculation if their height and position are unclear. To guarantee accuracy, it has been necessary to place calibration points (targets with known coordinates) separately and match them to the point cloud. Thus, although the potential for on-site point cloud acquisition has increased, several challenges remained for achieving the ideal of “anyone easily completing high-precision point cloud measurement on site” using only conventional technologies.

Immediate Volume Calculation via Cloud Processing

The key technology that solves these problems and enables completing point cloud volume calculation on-site is cloud processing. Processes that require time and computational resources, such as photo analysis and volume computation, can be executed rapidly 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 high-speed point cloud generation and volume calculation, volume computations that used to take half a day to several days can be completed the same day. For example, there are reports of drone aerial photography taking about 15 minutes, and with cloud processing, obtaining an as-built point cloud model and calculating volumes on the same day. This makes real-time quantity management—such as checking the as-built volume immediately after heavy equipment work—possible.

Results obtained via cloud processing can be shared instantly over the internet, eliminating the need to return to the office for data aggregation. Site staff can view cloud calculation results on a tablet or PC immediately and take additional photos or re-calculate on the spot if necessary. If the cloud service also hosts and visualizes point cloud data, you can display the 3D model and check volumes in a browser without specialized software. With immediate on-site volume calculation, if excavation is insufficient compared to the plan, you can immediately decide additional excavation areas; if embankment exceeds design, you can quickly plan removal of surplus soil—enabling rapid decisions without halting work. By leveraging the cloud, point cloud volume calculation has stepped into the realm of “real time” for the first time and is poised to transform construction management.

On-Site DX Accelerated by Data Sharing and Visualization

The benefits of handling point cloud data in the cloud go beyond speed. Using uploaded high-precision 3D data for visualization and sharing accelerates on-site DX. Point cloud models uploaded to the cloud can be easily shared among stakeholders; remote offices and clients (such as municipal staff) can check the site’s 3D status in a browser. Instead of explaining as-built conditions with pasted plan views and cross-sections in reports, point cloud data enable recreating the site interactively during explanations. For instance, on a cloud viewer you can freely rotate and zoom the point cloud model of the measurement area, display any cross-section on the spot, or show error as a color-coded heat map comparing to design—all with a click. This visual information makes it easier for site supervisors, construction managers, clients, and subcontractors to intuitively grasp the situation, shortening the time needed for explanations and discussions.

Point cloud utilization also improves efficiency in report creation and form output. Cloud systems can automatically aggregate volume computation results, immediately calculating embankment and excavation volumes while providing 3D models and comparison images as evidence that are easy to screenshot. Attaching these images and figures to as-built management documents produces highly persuasive reports, reducing time spent manually drafting drawings or pasting photos and allowing digital data to be directly repurposed for reporting—an advantage unique to DX. Recently gaining attention is AR (augmented reality) integration with point cloud data. By overlaying acquired point cloud models or design 3D data onto real scenery through a tablet or smartphone camera, as-built inspection and construction checks can be performed intuitively. For example, holding a tablet over an embankment in progress and overlaying the design model and current terrain point cloud with color-coding makes it instantly clear which parts need to be cut or filled by how many centimeters (inches). This AR visual support helps prevent mistakes while fully leveraging the precise data from point cloud measurements in field operations, and is attracting strong expectations as the next development in on-site DX.

Schedule Reduction Achieved by Real-Time Volume Management

Introducing point cloud volume measurement and immediate cloud processing directly contributes to shortening overall construction schedules. Traditionally, calculating volumes via manual surveying required many steps, and on large sites surveying teams could take several days to a week to measure as-built conditions, create drawings, and compute volumes. For example, a development site once required four people a full week (a total of 20–30 person-days) to perform topographic surveying, cross-section creation, and volume calculation. Switching to photogrammetry and point cloud processing reduced that to two people in one day (2 person-days) in a reported case. Drone aerial photography captured several dozen photos from above, and cloud processing enabled point cloud generation and volume calculation on the same day. Using point clouds dramatically compresses the personnel and time required for surveying work. Freed personnel can be assigned to other tasks, raising overall productivity.

Enabling rapid as-built measurement also shortens the entire construction cycle. In the past, subsequent steps were often delayed until survey results were available, but with near-real-time volume data, you can check differences between as-built and design on site and take immediate action. Regular point cloud surveys provide daily numerical progress of earthworks, allowing objective weekly or monthly progress evaluations and early countermeasures when needed. For example, if you take drone aerial photos every weekend and save point cloud models, you can graph weekly embankment volume increases or visualize where and how much material was added since the previous week using color-coded maps. Such time-series volume management makes it easy to take preemptive actions—such as increasing heavy equipment—against schedule delays, accelerating the PDCA cycle of construction management. As a result, projects can be completed with schedule margins or, in some cases, overall schedules can be shortened. The combination of point cloud volume calculation and immediate cloud processing yields not only surveying efficiency but also significant time savings and productivity improvements across the entire site.

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

A solution that makes the immediate application of point cloud volume calculation easy for anyone is LRTK. LRTK is a modern system that attaches a palm-sized high-precision GNSS receiver (RTK-GNSS) to a smartphone and uses a dedicated app to perform point cloud measurement via photo capture or LiDAR scanning. This allows centimeter-level (cm-level accuracy, half-inch accuracy) 3D surveying that previously required expensive surveying equipment to be casually performed with an everyday smartphone. If a site manager walks around an embankment site scanning with a smartphone in hand, a high-precision 3D model with position coordinates is generated on the spot, enabling direct measurement of terrain volumes and distances in the field. Acquired data can be synchronized to the cloud instantly, allowing real-time on-site volume calculation and construction decisions without returning to the office. Tasks that took days when outsourced to specialized surveyors can be completed quickly by in-house staff, making LRTK a powerful tool for DX promotion even at small and medium construction companies or sites.

Moreover, mobile measurement devices like LRTK have high compatibility with the aforementioned AR technology, suggesting future development into construction support tools. If point cloud data and design 3D models acquired by LRTK are overlaid on a smartphone or tablet screen, as-built confirmation and staking-out work can be performed more intuitively on site. In practice, LRTK apps let you upload acquired point clouds to the cloud so office PCs can review them, and on-site tablets can overlay design data with scan point clouds for display. For example, in slope works, overlaying the design slope model and current point cloud in AR lets you check surface irregularities on the spot and identify areas needing touch-up. The fusion of smartphone RTK devices with point cloud and AR has the potential to elevate site management to the next stage. As more user-friendly measurement technologies spread, a time will come when anyone—not just construction managers or surveying professionals—can handle 3D data as a matter of course.

Conclusion

Efforts to instantize volume calculation from point cloud data through cloud processing greatly contribute to digital transformation (on-site DX) and productivity improvements in construction management. Tasks that once required significant effort and time can now be carried out faster, more accurately, and more safely by leveraging familiar tools such as smartphones and drones together with the cloud. Regardless of role—construction manager, surveyor, municipal staff, or ICT promoter—the common benefit is comprehensive data-driven situational awareness and rapid decision-making. Solutions like the LRTK series support high-precision positioning and point cloud processing on construction, civil engineering, and surveying sites, enabling shorter working times and dramatic productivity gains. LRTK is compatible with the Ministry of Land, Infrastructure, Transport and Tourism’s i-Construction initiative and is one of the optimal platforms to drive industry-wide digitalization. For details, please also visit 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 evolve your site to the next stage.

FAQ

Q1. How accurate is volume calculation using point clouds? A1. If measurement conditions are properly met, combining drone photogrammetry with RTK-GNSS positioning can achieve accuracy on the order of several centimeters (a few inches). There are field examples where volumes calculated from point clouds obtained by photogrammetry fell within ±1–2% of traditional survey calculations. Using expensive laser scanners can achieve millimeter-level precision, but for typical earthwork as-built quantity management, photogrammetry plus high-precision GNSS is sufficiently practical.

Q2. Is a drone mandatory to acquire point cloud data? A2. Not necessarily. Drone aerial photography is effective for large sites because it can capture wide areas in a short time, but for narrow sites or localized measurements, point cloud generation from smartphone or handheld camera photos is possible. Recently, solutions that combine a smartphone with a small GNSS receiver to easily perform high-precision point cloud measurement (e.g., LRTK) have emerged. Choose the optimal measurement method according to site scale and conditions.

Q3. Can point cloud data from photogrammetry be used for official as-built inspections? A3. Yes. As part of the “i-Construction” initiative, the Ministry of Land, Infrastructure, Transport and Tourism provides trial procedures for as-built management using UAV photogrammetry, and point cloud data from photogrammetry can be used for as-built quantity determination if certain accuracy verification procedures are met. Specifically, it requires measuring accuracy at check points placed before and after shooting and confirming that vertical errors fall within a prescribed range (for example: within 5 cm (2.0 in)). Many regional bureaus and municipalities have begun operations following these guidelines, so verify the latest procedures before use.

Q4. What is the difference between photogrammetry and 3D laser scanners? A4. Photogrammetry’s advantages are lower equipment cost and the ease of measuring wide areas at once. Because models are generated from color photos, they produce visually intuitive 3D models. However, accuracy is sensitive to shooting conditions and surface characteristics, and it can struggle to reproduce scenes at night or monotonous terrains lacking features. Photo data processing also takes time. On the other hand, 3D laser scanners require high initial investment but provide stable, high-precision measurements and can acquire data even in dark areas or under some vegetation. They struggle with targets like glass or water that reflect or transmit laser beams. In general, photogrammetry is strong in “speed and ease,” while laser scanning is strong in “precision and versatility.” It is ideal to choose or combine methods according to site conditions and required accuracy.

Q5. Can point cloud volume calculation be done without special software or expertise? A5. Recently, more user-friendly point cloud processing software and cloud services have emerged, making semi-automatic volume calculation possible without specialized skills. Some drone manufacturers’ analysis software and construction-oriented 3D volume calculation tools can automatically perform point cloud generation and volume calculation simply by uploading photo data. However, even though tools are becoming easier to use, accuracy management of measurement procedures remains important. Adhering to shooting guidelines and checking generation results for obvious anomalies, along with basic surveying knowledge and habitual data checks, will ensure reliable outcomes.