Table of Contents

• Why on-site earthwork volume management (volume calculation) is required

• Traditional earthwork calculation methods and their challenges

• What is a smartphone-integrated earthwork calculation tool

• How anyone can perform fast, high-precision surveying

• Benefits of on-site data sharing via cloud integration

• Effects smartphone surveying tools bring to the field

• Simple surveying with LRTK

• FAQ

Why on-site earthwork volume management (volume calculation) is required

At construction and land development sites, accurately understanding the earthwork volume—the volume of excavated or fill material—is critically important. For as-built verification and reporting to clients, you must always know “how much earth has been moved” and “how much more needs to be filled or excavated.” However, traditionally it has not been easy to calculate volumes immediately on site. The common practice was to hire surveying specialists to perform meticulous measurements, bring that data back to the office, and then analyze and compute volumes, which took time to produce results. As a result, even if site staff wanted to know the exact volume “right now, on the spot,” they often could not get an immediate answer and had to rely on experience and intuition to make decisions.

In recent years, addressing labor shortages and reforming work styles have become major issues in the construction industry, and efficient construction management methods are in high demand. With the Ministry of Land, Infrastructure, Transport and Tourism–led promotion of *i-Construction*, digitization of the field—so-called on-site DX—is progressing rapidly. Against this backdrop, expectations for “tools that can calculate volumes (earthwork) on site” have grown even higher. If a tool could provide immediate on-site volume measurements, site staff could verify as-built conditions without survey specialists, dramatically improving construction progress management. Knowing accurate quantities at the necessary timing prevents rework and enables faster decision-making, ultimately contributing to overall productivity improvements in construction.

Traditional earthwork calculation methods and their challenges

Until now, the following traditional methods have mainly been used to calculate earthwork volumes on site. Each has its advantages, but all faced challenges in delivering accurate on-site volume results immediately.

• Surveying with a Total Station (TS): This method sets up an electronic distance meter (total station) to measure the elevations and positions of many points on site, creates a terrain model, and calculates volumes. Although very accurate, measuring a large number of points on a large site takes time and requires specialized surveying personnel and assistants. From measurement to volume calculation involves considerable effort and days of work, so this method is not suitable for “producing immediate results on site.”

• Average cross-section method for volume calculation: This long-standing method in roadworks creates cross-sectional drawings at regular intervals, calculates cut and fill volumes for each segment on paper, and sums them. The principle is simple, but it cannot fully reflect terrain changes between sections and yields approximate values. Because surveying and drawing/calculation take time, it is unsuitable for real-time understanding.

• Photogrammetry using drones: A recently widespread approach uses drones to capture aerial photos of a site, then photogrammetry software to create 3D models and contours from images to calculate volumes. It is effective for efficiently covering wide areas, but is susceptible to weather and wind and requires flight-permit procedures. Processing the captured imagery requires expertise, and obtaining results immediately after capture is difficult in practice. A certain amount of time and post-processing is unavoidable to know volumes on site immediately.

• Visual estimation based on experience: In some cases operators or site supervisors estimate roughly “equivalent to X dump truckloads” based on experience. However, human-based estimates tend to have large errors and can lead to mismatches with clients’ expectations or disputes during as-built inspections (quantity checks).

As the above shows, traditional earthwork calculation methods had issues such as requiring time and effort, needing specialized skills, and lacking real-time capability. Even when one wants accurate quantities immediately, the time lag from measurement to analysis made on-the-spot answers difficult. Communicating quantities only as numbers is not intuitive, and requiring paper drawings or tables for explanation consumed time and effort to share status with clients or other departments.

What is a smartphone-integrated earthwork calculation tool

To solve these challenges, a smartphone-integrated earthwork calculation tool has emerged. This is a new measurement system that combines a small positioning device attached to a smartphone, a dedicated app, and a cloud service. Simply attach the pocket-sized device to your smartphone and the phone you normally use instantly becomes a high-precision surveying instrument.

The main components of a smartphone-integrated tool are as follows.

• High-precision GNSS receiver: A GPS receiver that attaches externally to a smartphone. It supports RTK (Real Time Kinematic) GNSS and, by applying correction information to satellite positioning, achieves high positioning accuracy within a few centimeters (a few inches). Built-in smartphone GPS typically has errors on the order of a few meters (a few ft), but using this external GNSS receiver makes it possible to measure positions with accuracy comparable to surveying instruments.

• Smartphone built-in sensors (LiDAR and camera): Recent smartphones include LiDAR (laser-based ranging) scanners and high-performance cameras that can scan surrounding terrain and structures to obtain 3D point cloud data. This records fine terrain undulations as digital data, which is useful later for precise volume calculations.

• Dedicated surveying app: An app that runs on the smartphone. It acquires high-precision position information from the positioning device while processing point clouds and image data obtained from the phone’s LiDAR and camera in real time. It also includes analysis functions such as volume calculation, enabling on-site volume computation. The user interface is designed to be intuitive so that, by following on-screen prompts and moving the phone, anyone can perform measurements.

• Cloud integration service: A service to save and share data obtained by the surveying app via the internet. Uploading 3D models and numerical data created on site to the cloud allows office PCs or members at other sites to view the information immediately. Point cloud data and volume results can be viewed in a browser without special software, enabling remote reporting and discussion.

Using such a smartphone-integrated tool makes high-precision surveying—previously requiring large equipment and skilled technicians—vastly more accessible. There is no need to carry heavy tripods or surveying instrument bodies; a smartphone and a small device can cover wide surveying areas. It is truly an innovative solution that enables “anyone to easily calculate earthwork volumes.”

How anyone can perform fast, high-precision surveying

The reason measurements with smartphone-integrated tools are both fast and high-precision lies in their technical mechanisms. Let’s highlight the points that allow high precision with operations simple enough for anyone on site.

First, RTK-capable high-precision GNSS is key to improving accuracy. A small GNSS receiver connected to the smartphone uses correction information from a base station (or augmentation signals from quasi-zenith satellites) to achieve consistent centimeter-level positioning (half-inch accuracy). Because positioning accuracy is high, acquired point cloud data and measured points are assigned absolute coordinates, allowing on-site measurements to be compared directly with design coordinate systems or reference surfaces. Traditionally, coordinate alignment (transforming to survey coordinates) was required after laser scanning, but smartphone-integrated tools can determine accurate position coordinates simultaneously with measurement.

Next, the smartphone’s built-in LiDAR sensor and camera accelerate measurement through 3D scanning. Simply walking around a stockpile or excavation site while holding the phone, the LiDAR acquires hundreds of thousands of ranging points per second and instantly generates a point cloud. Combining this with the high-precision position information mentioned above enables immediate dimension and volume calculations on site. Normally, processing point cloud data from 3D scans on a PC took significant time, but smartphone-integrated tools perform automatic processing within the app, so results are available almost simultaneously with measurement.

Augmented Reality (AR) technology is also utilized. By overlaying virtual measurement results on the live camera view, understanding the results becomes highly intuitive. For example, overlaying a color-coded heatmap or numerical display on site video to indicate “how many cm (in) more to excavate to reach the design surface” makes it easy to see excesses or shortfalls at a glance. Even inexperienced workers can quickly grasp the situation through visual information and make appropriate decisions on the spot.

Additionally, the user interface of the app, designed for ease of use, is an important factor. Users select a surveying mode for the target, follow on-screen guidance, and the app automatically acquires and analyzes data. Positioning status and accuracy are displayed in real time, giving first-time users confidence that they are measuring correctly. The interface minimizes technical jargon and allows simple button operations, making the tool usable even by those not comfortable with machinery.

Benefits of on-site data sharing via cloud integration

Smartphone-integrated tools are not just fast at measurement; their value is amplified by cloud integration. Uploading data collected on site to the cloud allows all geographically dispersed stakeholders to share information.

For example, if you upload volume measurement results to a shared corporate site immediately after measuring on site, headquarters or members at other sites can view the information at once. Since 3D point cloud models, photos of measurement locations, and calculated volume numbers can be inspected on the cloud, stakeholders can grasp the situation remotely with a sense of presence. This enables quicker reporting to the site agent or supervisors and allows immediate additional instructions if necessary.

Storing data on the cloud also makes it easy to manage daily progress data chronologically. If you scan excavation areas and record volumes at the end of each day, you can view the progress of as-built quantities over time on the cloud. When verifying “when and how much earth was removed” or “how far progress is relative to design quantities,” having organized cloud data streamlines the review process.

Of course, cloud upload can be flexibly chosen according to project needs. Sensitive data can be kept local while only necessary information is securely shared with one click. Eliminating the need to hand over paper documents or USB drives and enabling “measure on site and share immediately” is a major advantage that supports on-site DX.

Effects smartphone surveying tools bring to the field

Introducing a smartphone-integrated surveying tool brings various effects to civil construction management sites. Below are the main benefits.

• Optimization of construction planning and progress management: Immediate access to volume data allows on-the-spot adjustments to construction plans and heavy equipment deployment. For example, if excavation is found to be more than planned, you can promptly arrange additional dump trucks. Always knowing accurate progress quantities enables efficient plan changes and can shorten construction schedules.

• Prevention of mistakes and rework: Because discrepancies between the design and actual conditions can be visually confirmed on site, over-excavation or overfilling can be prevented in advance. Deviations that previously surfaced only during as-built inspections can be corrected immediately through real-time measurement, reducing rework, preventing unnecessary costs, and shortening schedules.

• Improved communication: Sharing digital 3D data and AR displays accelerates information exchange between the field, the office, and clients. Visual data greatly speeds consensus building compared with text- or number-only reports. Having objective data facilitates smoother discussions during progress assessments and on-site inspections.

• Contribution to skill transfer and human resource development: Because surveys can be performed with simple smartphone operations, junior staff and new employees can be entrusted with on-site surveying. Tasks that relied on veteran experience and intuition can be supplemented by the tool, helping to reduce reliance on individuals. Even without experienced personnel, measurements can be performed to a consistent quality, aiding efforts to counter labor shortages.

• Improved safety: Measurements can be taken remotely from safe locations for dangerous slopes or deep excavations. Traditional surveys in unstable terrain carried fall risks, but smartphone surveying avoids needing risky postures. AR displays can also be used to highlight hazardous areas, providing safety-management benefits onsite.

Thus, smartphone-integrated tools for on-site volume calculation not only streamline surveying work but also generate positive ripple effects across construction management. Real-time, accurate data speeds decision-making on site and improves overall productivity and safety, making these tools potential game-changers for on-site DX.

Simple surveying with LRTK

One example of such an innovative smartphone surveying tool is simple surveying using LRTK. LRTK is a system developed by Reflexia Co., Ltd., consisting of a smartphone-integrated high-precision GNSS receiver and a cloud service, used by attaching it to iPhone or Android smartphones. By using the dedicated LRTK app to perform 3D scans and positioning on site, anyone can quickly perform precise earthwork volume calculations.

With LRTK, you no longer need to carry a heavy total station; surveying can be completed with a palm-sized device. For example, to measure the volume of a fill or backfill area, simply walk around the target while scanning with a smartphone fitted with LRTK, and the volume in cubic meters (m^3, ft^3) will be calculated on the spot. Measurement results can be viewed immediately on the smartphone screen and synchronized to the cloud with one touch for internal sharing. The ability for site personnel to obtain and utilize necessary data without waiting for a surveying team is a major strength.

LRTK surveying is designed to be easy to use even for beginners. The app displays instructions in Japanese and shows operation guides for each surveying mode, so those unfamiliar with machine operation can use it comfortably. If you encounter difficulties on site, you can have a supervisor or technician in a remote location review the uploaded cloud data and provide advice, ensuring full support.

If you are currently looking for a “tool that can calculate volumes on site,” simple surveying with LRTK is a strong option. For sites aiming to streamline and reduce labor in earthworks, smartphone-based surveying using the latest technologies is now indispensable. Please consider introducing it to your site.

FAQ

Q: What exactly is a smartphone-integrated earthwork calculation tool? A: It is a system in which a small high-precision positioning device is attached to a smartphone and a dedicated app is used to measure and calculate earthwork volumes. The system dramatically improves smartphone GPS accuracy and automatically computes volumes from 3D data captured by the phone’s camera and LiDAR. In short, your everyday smartphone becomes a precision surveying instrument.

Q: Can people without surveying expertise use it? A: Yes. Complex settings and calculations are handled automatically by the tool, so it is designed for anyone to use. Measurement is completed simply by moving the smartphone according to the app’s prompts, so even those with little experience can use it confidently. You can start using it intuitively without lengthy training.

Q: What level of accuracy can be expected? A: With GNSS RTK, under ideal conditions horizontal positioning accuracy of about ±2–3 cm (±0.8–1.2 in) and vertical accuracy on the order of a few centimeters can be expected. In actual field conditions, centimeter-level accuracy (half-inch accuracy) allows earthwork volumes to be determined to a high degree comparable to traditional optical surveying instruments.

Q: What are the advantages compared with drone surveying? A: Smartphone-integrated tools are more convenient than drones and can be used immediately by anyone on site. They do not require flight permissions or worry about weather, making them suitable for everyday use even on small sites. Real-time results allow immediate application to construction. However, for very large survey areas, drones may be more efficient, so it is best to choose the method according to the application.

Q: How are measured data saved and shared? A: Measurement data are saved on the smartphone and can be uploaded to the cloud as needed. Once stored on the cloud, point cloud data and measurement results can be reviewed via a browser on office PCs, and shareable links can be sent to stakeholders. Data can also be exported as 3D models or CSV files for internal reporting or further analysis with other software.