On-site Instant Soil Volume Measurement for Surveying DX! Point Cloud Scanning × AR to Visualize the Entire Site

In roadworks, slope shaping, embankment/cutting works, and land development sites, accurately measuring and managing the volume of earth (soil volume) is indispensable. Traditionally, soil-volume calculations were performed by surveying on-site, drawing cross sections, and calculating volumes using methods like the average cross-section method, which was very labor-intensive. But now an era is approaching in which you can calculate soil volumes instantly on-site and verify them immediately.

The key is the use of 3D point cloud scanning technology and AR (augmented reality). By scanning the entire site to create a digital point cloud model and visualizing that data overlaid on the real world with AR, you can quickly and accurately grasp soil volumes while on site. This kind of business transformation through digital technology—so-called surveying DX (digital transformation)—not only dramatically improves work efficiency and accuracy but also offers significant benefits in safety and information sharing, making it a promising solution for labor-saving in the construction industry, which faces serious labor shortages. It is attracting attention now.

Table of Contents

• What on-site instant soil volume measurement is

• Challenges of traditional soil-volume measurement

• Instant wide-area measurement with point cloud scanning

• Site visualization using AR technology

• Use cases: roadworks, slope shaping, etc.

• Benefits brought by digital measurement

• Simple surveying with LRTK

• Frequently Asked Questions (FAQ)

What on-site instant soil volume measurement is

"On-site instant soil volume measurement" refers, as the name implies, to measuring soil volume immediately on site. Normally, it can take several days from surveying to calculating volumes and reporting, but if instant measurement is realized, you can understand embankment and excavation volumes on the spot during work and immediately reflect them in construction. If construction managers can check soil volumes whenever needed, they can quickly respond to delays or excesses/shortfalls, leading to waste-free schedule management.

What makes this instant soil-volume understanding possible is the recent emergence of digital surveying technologies. For example, if you scan the current terrain on-site immediately after a day’s excavation work, you can understand deviations from the design on the same day and revise the next day’s construction plan immediately. Traditionally, progress verification required several days and always bore the risk of excesses or shortages, but instant measurement can eliminate such worries. Rather than measuring one point at a time by hand, 3D scanning measures the entire terrain in a short time and automatically calculates volumes from that data. Moreover, it is important that you can check measurement results while being on site. For instance, calculation results may be displayed on a tablet on the spot, or, as described later, overlaid on the site via AR, allowing decisions to be made on site without returning to the office. This enables real-time data utilization and advances the smartification of construction management.

Challenges of traditional soil-volume measurement

Traditional soil-volume measurement generally involved surveyors measuring heights at regular intervals on site, creating cross sections from those measurements, and calculating volumes. The average cross-section method requires many measurement points to determine the volume of a wide area, meaning both measurement and calculation take time and manpower. In addition, measurement points cannot be taken on steep slopes or areas with poor footing where people cannot enter, so volumes for those parts had to be estimated. Because estimates are derived from limited points, precision and detail are inherently limited, and small local irregularities or localized excesses/shortfalls can be overlooked. Therefore, frequent soil-volume measurement was not realistic, and daily management sometimes estimated soil volume from factors like the number of dump trucks, but such methods are limited in accuracy and prone to errors and misunderstandings.

Furthermore, the lack of immediacy in manual surveying was a major problem. If it takes several days from measurement to drafting and calculation, site conditions can change in the meantime. Real-time capabilities are essential for rapid decision-making, but traditional methods could not provide that, so even if excesses or shortages were noticed during construction, corrections might be delayed. In fact, there are reports where soil-volume measurement that previously took several people several days was changed to creating a point cloud model from drone photogrammetry and calculating volume, and it was completed in one day. Thus, traditional methods had limitations in both efficiency and accuracy, and there was significant room for improvement toward site DX.

Instant wide-area measurement with point cloud scanning

The trump card to solve the above challenges is 3D point cloud scanning. Using laser scanners, drone aerial photography (photogrammetry), or short-range smartphone-mounted LiDAR, the site’s shape is captured as a set of innumerable points (a point cloud). While traditionally people measured one point at a time, point cloud scanning enables surface and continuous measurement with machines or cameras, allowing detailed data to be obtained over a wide area in a short time. You can measure necessary dimensions and volumes later on the acquired point cloud data, effectively recording the terrain as a "digital copy of the entire site."

With point cloud data, you can compare terrain models before and after excavation or embankment to determine the volume difference. High-density data comprising millions of points can account for fine undulations, enabling more accurate soil-volume calculations than traditional methods. Also, once a point cloud is acquired and stored, you can cut arbitrary sections later and recalculate volumes, supporting flexible analyses. Recently, software that automatically calculates volumes from point cloud data and outputs reports has become widespread, greatly shortening data processing time. Because of these advantages, point cloud measurement is rapidly spreading in the civil engineering industry, and its speed and precision are valued and actively encouraged in industry DX promotion initiatives such as the Ministry of Land, Infrastructure, Transport and Tourism’s i-Construction.

Site visualization using AR technology

Digital information such as point cloud data can be used intuitively with AR (augmented reality). AR is a technology that overlays design data and measurement results on the real-world image displayed on a tablet or smartphone screen. With this, simply pointing a camera on site can visually convey information such as "where and how much embankment is needed here" or "which parts have been over-excavated."

If you display the difference between the completed design model and the current point cloud survey data on the ground with color coding, it becomes immediately clear which points are higher or lower than the design. For example, by using green for "as designed," blue for "over-excavated (lower than design)," and red for "over-embanked (higher than design)," you can intuitively indicate areas with large differences. By overlaying such a heatmap on the terrain with AR, you can walk the site and find problem areas. Variations in construction that are hard to understand from drawings or numerical lists become clear as visualized on the spot, clarifying points that need correction and greatly contributing to quality control and prevention of rework. Also, because workers can share the screen and check conditions together, communication is smoothed. Furthermore, by using AR you can virtually display the designed final shape or guideline on site so operators and workers can reference it during construction. For example, showing the boundary lines of the planned excavation area or the target height surface on the ground with AR makes it obvious how much soil to remove, leading to accurate work not based on guesswork. In the future, applications such as using dedicated AR glasses to display necessary information in a worker’s field of view without using hands are also expected.

Use cases: roadworks, slope shaping, etc.

When soil volume can be measured instantly, efficiency improves across various civil and construction sites. The benefits of on-site instant soil volume measurement are demonstrated in cases such as:

• Roadworks: Immediately after construction of the roadbed or pavement, point cloud measurement can verify whether heights and slopes match the design. This allows detection of shortages or excesses before paving and early correction.

• Slope shaping: For slope shaping of development land or road slopes, it is important to confirm that earth is cut in accordance with the designed slope. By overlaying a 3D-scanned terrain model with the design model and displaying slope lines on site via AR, you can check for uncut or overcut areas on the spot.

• Embankment and cutting works: In large-scale earthworks, it is necessary to know how much the soil volume has changed day by day. Regularly scanning the entire site with drones or LiDAR lets you automatically aggregate the amount of embankment or excavation in software, helping with progress management and reviewing soil transport plans.

• Land development: In wide-area land development sites such as residential land preparation, it is necessary to cut and fill to the specified heights and level the surface. Scanning the completed shape and comparing it with the design reference surface allows you to identify areas that are still low or overly filled across the surface. Sharing a 3D model among stakeholders helps the whole team share a common understanding of the terrain’s final appearance.

Benefits brought by digital measurement

Finally, here are the main benefits of introducing digital measurement using point cloud scanning and AR.

• Significant reduction in work time: Soil-volume calculations that took days with manual surveying can be completed on-site the same day with digital measurement. Reduced waiting time for measurement results shortens construction schedules and greatly reduces required personnel, leading to cost savings.

• Improved measurement accuracy and quality: High-density point cloud data allows detection of details that could not be grasped before. Small deviations from the design can be visualized, reducing variability in construction quality and improving as-built management accuracy. In addition, objective 3D data can be provided as evidence of as-built conditions and quantities, smoothing recognition sharing with clients and stakeholders and facilitating inspections and discussions.

• Improved safety: Drone or remote measurement can replace surveying on dangerous slopes or measurements on roads where vehicles run. Because data can be acquired without people entering hazardous areas, it reduces risks in field operations.

• Immediate decision-making: Real-time on-site understanding of conditions enables revisions to plans or decisions on additional measures to be made the same day. Data-driven rapid decision-making helps prevent rework and material waste.

• Data sharing and long-term utilization: Digitized survey data can be shared instantly via the cloud and synchronized with remote offices. Point cloud data at project completion becomes a "3D record of the site" and serves as an asset for future maintenance and renovation planning.

Simple surveying with LRTK

The recently emerged LRTK is attracting attention as a simple surveying solution using smartphones. By attaching a small high-precision GNSS receiver to a smartphone and performing RTK positioning (real-time kinematic), while scanning the site with the smartphone’s built-in LiDAR or camera, you can add centimeter-level positioning information to the acquired point cloud data in real time (cm level accuracy (half-inch accuracy)). Traditionally, post-processing or control-point surveying was required to align 3D point clouds to map coordinates, but with LRTK you can obtain point cloud data that is already accurately georeferenced at the time of scanning, which is a major advantage.

With just this palm-sized device and a smartphone, a single person can easily perform 3D surveying while walking around the site. Even without expensive dedicated equipment or specialized skills, your usual smartphone can quickly become a surveying instrument. Acquired data is automatically saved to the cloud, making it smooth to check or share what was measured on site with the office immediately. Enabling on-site personnel to measure without relying on specialist operators means a time is approaching when anyone can easily practice high-precision surveying. LRTK is already being used widely not only in roadworks and land development sites but also in disaster response, and its usefulness is being demonstrated.

For advancing site DX, such smartphone measurement technologies become powerful tools. The experience of "instant soil volume on site" with point cloud scanning × AR is so convenient that once you use it you won’t want to let it go. Actively adopt the latest technologies and bring the wave of surveying DX to your site. It will surely dramatically improve the efficiency and accuracy of your construction management.

Frequently Asked Questions (FAQ)

Q1. What methods are available to measure soil volume instantly on site? A1. Typical methods include point cloud measurement with 3D laser scanners and photogrammetry that creates 3D models from drone aerial photographs. Recently, methods using smartphone or tablet-built-in LiDAR sensors to easily acquire point clouds have also emerged. In all cases, volumes can be quickly determined on site by calculating volumes from the acquired 3D data using dedicated software.

Q2. Do I need expensive dedicated equipment to measure? A2. No, it is not always necessary. Drones and high-performance laser scanners are effective for efficiently measuring wide areas, but even without them, you can manage with creative approaches. For example, you can generate point clouds by taking many photos from the ground with a smartphone or digital camera, or you can scan nearby terrain with the LiDAR sensor of the latest smartphones or tablets. By using small GNSS receivers that attach to smartphones (e.g., LRTK), an environment is emerging where you can perform high-precision point cloud measurements with a handheld smartphone even without drones or expensive equipment.

Q3. What is the accuracy of soil-volume calculation from point clouds? A3. It depends on conditions, but with proper measurement and processing, errors are often within a few percent. Field verifications have reported cases where differences from traditional surveying calculation results were around 1%. However, to ensure high accuracy it is important to obtain high-quality photos (or scan data) with sufficient point density and to improve coordinate accuracy of the model by performing positioning alignment with RTK-GNSS or known control points.

Q4. Can it be used without specialized knowledge? A4. Yes. Modern smartphone measurement apps are designed to be intuitive and can be used without specialized surveying knowledge. Complex calculations are handled automatically by the software, so users can complete surveying with simple steps like pressing a scan start button. Tools that site personnel can use as an extension of daily work are increasing, and with short training or trials, anyone can obtain high-precision measurement results on site.

Q5. What is LRTK? A5. LRTK is the name of a new solution that combines smartphones with RTK-GNSS technology to realize high-precision surveying. By attaching a small RTK-capable GNSS receiver to a smartphone and performing photo capture or LiDAR scanning, you can add high-precision positioning information to the acquired point cloud data in real time. The biggest advantage of using LRTK for soil-volume calculation is that the point cloud model is obtained already aligned to the survey coordinate system, eliminating the need for post-processing alignment. In other words, even non-experts can easily acquire accurate point clouds and immediately calculate excavation and embankment volumes for on-site use.

Q6. How should we start introducing new surveying technologies? A6. We recommend starting with small sites or trial scans. Choose methods that fit your site, such as drone measurement or smartphone measurement, and have a small team become familiar with the operation. For example, if using a smartphone, try a simple surveying device like LRTK on site to experience its ease and accuracy. Share measured data internally and compare it with traditional methods to verify effects. With support or training from vendors as needed, you can smoothly proceed with introduction.

Q7. Is processing large amounts of point cloud data difficult? A7. Previously, high-performance PCs and specialized software were required, and data processing could be a burden. However, cloud services and automated analysis tools have become more plentiful, and environments are now available where uploading point cloud data acquired on site automatically performs volume calculations and drafting. In smartphone measurement cases, dedicated apps provide user-friendly interfaces and automatic processing so users can obtain results without worrying about complex operations. Thus, even with large data volumes, technical hurdles are decreasing and the handling will become even easier in the future.