Table of Contents

• Why tools that can calculate earthwork volume on-site are needed

• Traditional methods of calculating earthwork volume and their challenges

• What a smartphone-integrated earthwork volume calculation tool is

• How high-speed, high-precision surveying anyone can do works

• Benefits of sharing site data via cloud integration

• Effects smartphone surveying tools bring to the site

• Simple surveying with LRTK

• FAQ

Why tools that can calculate earthwork volume on-site are needed

In civil engineering and site development, accurately grasping the earthwork volume (volume) of excavated or filled soil is extremely important. For as-built management and reporting to the client, it is necessary to always know how much soil has been moved and how much more filling or cutting is required. However, traditionally it has not been easy to instantly calculate earthwork volume on-site. It was common to request surveying specialists to take detailed measurements and then return to the office for analysis and calculation, meaning results took time to obtain. As a result, even when site personnel wanted to “know the exact earthwork volume here and now,” they could not get an immediate answer and often had to rely on experience and intuition to make decisions.

In recent years, the construction industry has faced major challenges such as labor shortages and the need to reform working styles, and efficient construction management methods are in high demand. The Ministry of Land, Infrastructure, Transport and Tourism-led promotion of *i-Construction* has also been a tailwind, and on-site digitalization, so-called on-site DX, is rapidly advancing. Against this backdrop, expectations are rising for tools that can perform real-time volume calculations (earthwork measurements) on-site. For example, if there is a tool that can calculate volumes on-site, site staff alone could check as-built conditions even without surveying specialists, greatly streamlining construction progress management. Being able to know earthwork volume immediately when needed helps prevent rework and enables rapid decision-making, contributing to overall site productivity improvements.

Traditional methods of calculating earthwork volume and their challenges

Until now, the following traditional methods have mainly been used to calculate earthwork volume at earthworks sites. Each has its strengths, but there are many challenges to obtaining an accurate earthwork volume immediately on-site.

• Surveying with a total station (TS): This method sets up an electronic distance meter and measures the elevations and positions of many points on-site to create a terrain model and calculate volumes. It provides high precision, but measuring many points over a large area takes time. It also requires specialized surveying technicians and assistants, and the measurement-to-calculation workflow takes effort and days, making it difficult to produce results on the spot.

• Average cross-section method: A traditional method used in roadworks and other projects. Cross-sections of the terrain are measured at regular intervals, and the fill/cut volume for each section is calculated from section drawings and totaled. It is a conventional method for rough estimates on drawings, but it cannot fully reflect fine terrain changes between sections and yields only approximate values. Surveying, drawing creation, and calculations also take time, making it unsuitable for applications requiring real-time volume information.

• Photogrammetry using drones: A recently popular method where a drone (UAV) photographs the site from the air, and photogrammetry software creates 3D models or contour lines to calculate volumes. It is effective for efficiently surveying wide areas, but it is affected by weather, requires flight permission applications, and needs specialized knowledge for data processing. It is difficult to complete shooting to analysis instantly, so there is inevitably a time lag before results are obtained.

• Visual estimates based on experience: Sometimes heavy equipment operators or site supervisors roughly estimate volume as “about how many truckloads.” However, judgments based on human intuition can have large errors and may lead to discrepancies with the client or disputes over measured progress.

As described above, traditional methods of calculating earthwork volume have issues such as being time-consuming, requiring specialist skills, and lacking real-time capability. Even if you want to know the exact volume immediately when needed, the time lag from surveying to analysis makes it difficult to answer on the spot. Also, explaining volume with numbers alone is not intuitive, and conveying conditions to clients or other departments using paper drawings and tables is cumbersome.

What a smartphone-integrated earthwork volume calculation tool is

To solve these challenges, a smartphone-integrated earthwork volume calculation tool has emerged. This is a new measurement system combining a small positioning device that attaches to a smartphone, a dedicated app, and a cloud service. Just attaching a pocket-sized device to your everyday smartphone transforms it into a high-precision surveying instrument.

Typical components of a smartphone-integrated tool are as follows:

• High-precision GNSS receiver: A small GPS receiver that attaches externally to a smartphone. It supports RTK (Real Time Kinematic) GNSS and, by adding correction information to satellite positioning, achieves positioning accuracy on the order of several centimeters (cm level accuracy (half-inch accuracy)). While a smartphone’s built-in GPS had errors on the order of meters, using this GNSS terminal yields surveying-equipment-level accuracy.

• Smartphone built-in sensors (LiDAR, camera): Modern smartphones are equipped with LiDAR (light-based ranging sensors) and high-performance cameras, enabling scanning of surrounding terrain and structures to obtain 3D point cloud data. This allows detailed terrain undulations to be recorded digitally, revealing areas that were previously difficult to visualize.

• Dedicated surveying app: An app running on the smartphone that acquires position information from the high-precision positioning device while processing the point cloud and image data obtained from the phone’s LiDAR and camera in real time. It also includes analysis functions such as volume calculation, making it possible to compute earthwork volumes immediately on-site. The interface is intuitively designed so that anyone can perform measurements simply by following on-screen instructions and moving the smartphone.

• Cloud integration service: A service that stores and shares the data acquired by the surveying app over the Internet to the cloud. Uploading 3D models and numerical data to the cloud allows office PCs and other team members to access information immediately. Even without special software, point cloud data and volumes can be viewed in a browser, smoothing reporting and consultation.

Using such smartphone-integrated tools brings high-precision surveying—previously requiring large equipment and specialist knowledge—within easy reach. There is no need to carry heavy tripods or total stations; a smartphone and a small terminal can cover wide sites. It is truly an innovative solution that makes “anyone can easily calculate earthwork volume” a reality.

How high-speed, high-precision surveying anyone can do works

The reason measurements using smartphone-integrated tools are both high-speed and high-precision lies in their technical mechanisms. Here we explain the key points that allow high precision with simple on-site operation that anyone can handle.

First, RTK-capable GNSS is the key to high precision. The compact GNSS receiver connected to the smartphone receives correction information from a base station (or augmentation signals from satellites), enabling centimeter-level positioning in real time. Because positioning is highly accurate, the acquired point cloud data and measured points are assigned absolute coordinates, allowing direct comparison with design drawings or reference planes on-site. Traditionally, after laser scanning, separate coordinate alignment was required, but with smartphone-integrated tools, coordinate determination is completed simultaneously with measurement.

Next, the smartphone’s LiDAR sensor and camera’s 3D scanning technology contribute to speed. Simply walking around the soil pile or excavation site while holding the smartphone allows the LiDAR to capture hundreds of thousands of distance points per second and instantly generate a point cloud. Combining this high-density point cloud data with high-precision position information enables on-the-spot dimension and volume calculations. Normally, processing point cloud data from 3D scans required time on a PC, but with smartphone-integrated tools, automatic processing occurs within the app, so results are obtained concurrently with measurement.

Additionally, AR (augmented reality) technology is used. Because virtual measurement results can be overlaid on live camera imagery on the smartphone screen, the results are very intuitive to understand. For example, based on acquired volume data, overlaying information such as “how many centimeters (how many in) more to excavate for the design surface to match” as a colored heat map or numerical display on the site image makes excesses and shortages obvious at a glance. Even inexperienced workers can visually understand conditions and make appropriate decisions on the spot.

A well-designed app UI that anyone can use is also important. By selecting a survey mode and following on-screen prompts to move the phone, data acquisition and analysis are performed automatically. Real-time displays of positioning status and accuracy let first-time users confirm whether measurements are progressing correctly. The interface minimizes technical jargon and is designed to be completed with simple button operations, so even those uncomfortable with machinery can use it without confusion.

Benefits of sharing site data via cloud integration

Smartphone-integrated tools are not just fast at measuring; their value is further enhanced by cloud integration. Uploading data acquired on-site to the cloud allows all stakeholders to share information regardless of location.

For example, if you upload on-site volume measurement results to the company’s shared site via the cloud immediately after measuring, headquarters or members at other sites can view that data right away. Since 3D point cloud models, photos of measurement locations, and calculated volume figures can be confirmed in the cloud, stakeholders can grasp site conditions remotely with a strong sense of presence. This makes reporting to the site agent and requesting instructions from superiors faster, enabling prompt additional decisions when necessary.

Also, storing data in the cloud makes it easy to manage daily progress data chronologically. For example, if you scan the day’s excavation locations and record volumes at the end of each day, you can view the progression of as-built conditions in the cloud. When later verifying “when and how much soil was transported” or “how far progressed relative to the design quantity,” having well-organized cloud data makes checks smooth.

Of course, uploading is optional. Highly confidential data can be kept locally, while only information that needs to be shared can be safely synced to the cloud with one click. This eliminates the hassle of passing around paper drawings or USB memory sticks, making “measure on-site and share immediately” the norm. This is another major benefit supporting on-site DX.

Effects smartphone surveying tools bring to the site

Introducing smartphone-integrated surveying tools brings various effects to earthworks construction management sites. Below are the main impacts.

• Optimization of construction planning: Because volume data can be obtained immediately, construction plans and heavy equipment deployment can be adjusted on the spot. For example, if excavation volume is found to be larger than planned, additional truck arrangements can be made early.

• Prevention of mistakes and rework: Visual confirmation of discrepancies between design drawings and actual conditions on-site prevents over-excavation or over-filling. Discrepancies that previously only became apparent at as-built inspections can be corrected immediately through real-time measurements, reducing rework, lowering costs, and shortening schedules.

• Smoother communication: Sharing digital 3D data and AR views speeds up information exchange between site, office, and clients. Visual data promotes consensus faster than textual or numerical reports. Objective data also facilitates smoother discussions during progress assessments and on-site inspections.

• Technical succession and human resource development: Because measurement is possible with simple smartphone-based operations, young or new staff can be entrusted with site measurements. The tool supplements parts that previously relied on veteran experience, helping reduce dependence on individuals. Even without experienced personnel, consistent-quality surveying becomes possible, aiding measures against labor shortages.

• Improved safety: Dangerous steep slopes or deep excavations can be measured non-contact from a distance. Traditional surveying in unstable footing posed risks, but smartphone surveying eliminates the need for risky postures. AR displays can also visualize no-entry zones, contributing to site safety management.

Thus, smartphone-integrated tools that can instantly calculate earthwork volume on-site do more than streamline measurement tasks; they produce positive ripple effects across construction management. With real-time, accurate data, on-site decision speed increases, improving overall productivity and safety. They are truly a trump card for on-site DX and are DX tools that can significantly transform traditional construction workflows.

Simple surveying with LRTK

As an example of the innovative smartphone surveying tools described above, there is simple surveying using LRTK. LRTK is a system developed by Refixia Inc., a startup from Tokyo Institute of Technology, consisting of a smartphone-integrated high-precision GNSS receiver and a cloud service. It is a compact device that attaches to iPhone and Android smartphones, and using the dedicated LRTK app to perform 3D scanning and positioning on-site makes precise earthwork volume calculations possible for anyone in a short time.

With LRTK, there is no need to transport heavy total stations; 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 object while scanning with a smartphone fitted with LRTK, and the cubic meters will be calculated on the spot. Measurement results can be checked immediately on the smartphone screen and synchronized to the cloud for internal sharing with a single button. The ability for site personnel to obtain and use necessary data without waiting for a specialized surveying team is a major advantage.

LRTK surveying is also designed to be easy for first-time users. The app displays Japanese and provides clear guides for each survey mode, so even those not comfortable with machinery can use it with confidence. If you encounter trouble on-site, you can share cloud data with a remote supervisor or technician for advice, so support systems are well established.

If you are looking for a “tool that can calculate earthwork volume on-site,” simple surveying with LRTK is a strong option. For sites aiming to improve efficiency and reduce labor in earthworks, smartphone surveying using the latest technology is now indispensable. Please consider testing it on your site.

FAQ

Q: What exactly is a smartphone-integrated earthwork volume calculation tool? A: It is a system where a small high-precision positioning terminal is attached to a smartphone and a dedicated app performs volume calculations. It dramatically improves a smartphone’s GPS accuracy and automatically calculates volumes from 3D data acquired by the camera and LiDAR. In short, it turns a smartphone into a precision surveying instrument.

Q: Can people without surveying expertise use it? A: Yes, it is designed for anyone to use. Measurement is completed simply by following the app’s on-screen prompts, so even those with little experience need not worry. The tool handles complex settings and calculations automatically, leaving the user to merely review the results. You can start using it intuitively without lengthy training.

Q: What level of measurement accuracy can be secured? A: Using GNSS RTK, under ideal conditions horizontal positioning accuracy on the order of ±2–3 cm and vertical accuracy of a few centimeters can be expected (cm level accuracy (half-inch accuracy)). In actual field conditions, centimeter-level accuracy enables earthwork volume assessments comparable to conventional surveying equipment.

Q: What are the advantages compared to drone surveying? A: Smartphone-integrated tools are easier to use and allow anyone on-site to measure immediately, without concerns about flight permissions or weather, and are practical for small-scale sites. They also provide real-time results that can be reflected in construction on the spot. However, for surveying very large areas, drones may be more efficient, so it is desirable to choose the method according to the use case.

Q: How are measurement data stored and shared? A: Measurement data are stored on the smartphone and can be uploaded to the cloud as needed. When stored in the cloud, point cloud data and results can be viewed from an office PC via a browser and shared with stakeholders via links. Data can also be exported in formats such as 3D models or CSV for use in internal reports or analysis with other software.