Point Cloud Scanning with a Smartphone! A High-Precision, Cloud-Connected Tool That Instantly Calculates Earthwork Volumes On Site

Table of Contents

• The need to instantly calculate earthwork volumes on site

• Conventional earthwork measurement methods and their challenges

• Emergence of tools that can scan point clouds with a smartphone

• Benefits of smartphone point cloud surveying

• Use of high-precision positioning technology (RTK)

• Data sharing via cloud connectivity

• Use cases on civil engineering construction sites

• Use cases on land development sites

• Use cases for disaster survey and recovery

• Smartphone simple surveying enabled by LRTK

• FAQ

The need to instantly calculate earthwork volumes on site

In civil engineering, land development, and disaster recovery operations, there is a strong demand for tools that can immediately calculate earthwork volumes on site. For example, if the volumes of excavation or embankment can be quickly identified, project scheduling and cost control become far more efficient. Until now, estimating earthwork volumes often relied on experience and intuition, and errors could lead to costly rework or increased expenses. Being able to calculate accurate earthwork volumes on the spot is indispensable for smooth construction progress and appropriate decision-making.

In recent years, the wave of DX (digital transformation) has also hit construction sites, and improving the accuracy of as-built management and progress measurement is being emphasized. Initiatives such as i-Construction led by the Ministry of Land, Infrastructure, Transport and Tourism are promoting the use of digital technology to streamline surveying tasks that used to be time-consuming, so the demand for such efficiency improvements continues to grow. Within this context, the arrival of earthwork measurement tools that site staff can easily use to get immediate results is highly anticipated.

Conventional earthwork measurement methods and their challenges

Traditionally, various methods have been used to calculate earthwork volumes on site. However, each method has challenges, making real-time, easy measurement difficult.

• Human surveying and calculation: Surveyors use transits or levels to collect control points and calculate volumes with methods like the average cross-section method. While accurate, this requires enormous effort and time and specialized knowledge. Calling in experts every time on a busy site is unrealistic.

• Estimation based on machinery counts or truck numbers: A simple method estimates volumes from the number of dump truck loads or the bucket capacity of excavators. However, this lacks precision and often deviates from actual volumes. It merely provides a rough estimate, not an accurate volume.

• Drone aerial photogrammetry: Recently, drones have been used to capture sites and generate 3D models or point clouds from photos to calculate volumes. This allows surveying large areas in a short time, but it requires flight permissions, specialist operators, and time and skill for image processing. It is also weather-dependent and not always suitable for “instant” results.

• 3D laser scanners: Ground-based high-precision laser scanners can also be used to obtain point clouds. They deliver very precise results, but the equipment is expensive and difficult to operate, and specialist technicians are required to rotate a single unit among sites. The data volumes are massive and processing burdens are high, so these systems are not something everyone on site can use casually.

As the above shows, conventional methods face challenges in "ease of use," "immediacy," and "versatility." Even if the latest equipment is introduced, it may not be usable on site or the data processing may take so long that the investment goes to waste. What was needed was a method that allowed anyone on a busy site to quickly measure earthwork volumes without special effort.

Emergence of tools that can scan point clouds with a smartphone

Responding to these needs, a new category of tools has recently emerged that enables point cloud scanning with a smartphone. By leveraging the smartphone’s camera and sensors and walking around the site while scanning terrain and embankments, detailed 3D data (point clouds) can be acquired in a short time.

For example, some recent high-performance smartphones incorporate small LiDAR sensors that can measure shapes several meters (several ft) ahead. Combined with photogrammetry techniques using multiple photos or video, it is also possible to generate point clouds of wider areas. In other words, without special surveying equipment, an everyday smartphone can quickly be transformed into a 3D measuring device.

Particularly notable are solutions that combine a smartphone with a high-precision GNSS (GPS) receiver. While a smartphone alone can capture shape using LiDAR or a camera, the positional accuracy of conventional GPS can have errors of several meters. By attaching a dedicated receiver that supports Real-Time Kinematic (RTK) to the smartphone, centimeter-level positioning (cm level accuracy (half-inch accuracy)) becomes possible. This allows high-precision coordinates to be directly assigned to the point cloud obtained with the smartphone, producing accurate 3D data aligned to the site coordinate system.

With this smartphone × high-precision GNSS combination, high-precision point cloud surveying with the simplicity of a single button press is becoming a reality even for non-specialists. By attaching a palm-sized device to a smartphone and carrying it, you can walk around a wide site and digitally capture the entire terrain. The troublesome control point surveys and post-processing previously required are minimized, and it is now possible to perform volume calculations from the 3D model created on the spot.

Benefits of smartphone point cloud surveying

Smartphone point cloud scanning offers many advantages that conventional methods do not. The main points are listed below.

• Speed and immediacy: Walking around the site and scanning for a few minutes can yield volume calculation results immediately afterward. You can, for example, measure in the evening and instantly confirm the day’s excavation quantities. Data processing is automated, greatly reducing waiting time for results.

• Ease and labor savings: All you need is a smartphone and a small device, eliminating the need to transport heavy equipment or perform complex setups. Anyone can measure using an intuitive smartphone app, and untrained workers can operate it. The convenience of “being able to pull it out of your pocket and measure anytime” is a major advantage on site.

• Improved safety: Even on dangerous slopes or where large amounts of loose material are piled, you can capture shapes by scanning from a distance with a smartphone. Measurements can be taken without personnel entering hazardous areas, contributing to worker safety.

• High-precision results: The combination of high-precision GNSS positioning and point cloud technology yields results that meet the accuracy required for volume calculations. It can achieve accuracy comparable to conventional manual surveying while covering wider areas, providing highly reliable data.

• Cost reduction: There is less need to outsource to specialists or purchase expensive equipment. Using smartphones reduces initial investment and allows in-house measurements when needed, offering excellent cost performance. On sites where each worker has a smartphone, it can truly serve as a “one-person, one-survey instrument.”

• Ease of continuous use: Tools that are difficult to operate or usable only by certain people tend not to persist. Smartphone point cloud surveying, by being “usable by anyone, anytime, anywhere,” can be integrated into routine site operations. It is easy to establish as a routine task, and as a result, overall surveying literacy on site improves.

Of course, smartphone-based simple surveying is inferior to ultra-high-precision stationary laser scanners in measurement range and accuracy. However, for as-built checks, small-scale volume confirmation, disaster records, and many other site tasks it delivers the necessary and sufficient accuracy. Above all, the ease of “being able to take it out of your pocket and measure” is the greatest asset for continued use on site. By casually measuring and accumulating data, construction management can take a step from reliance on intuition and experience to data-driven management.

Use of high-precision positioning technology (RTK)

A key component of smartphone point cloud surveying is high-precision positioning using RTK. RTK (Real-Time Kinematic) is a technique that uses correction information from a reference station to reduce GPS errors to centimeter levels. While typical smartphone GPS has errors of several meters, an RTK-capable receiver can determine horizontal and vertical positions with accuracy on the order of a few centimeters (a few in).

On construction sites, precise alignment with control points is required, so absolute coordinates in point cloud data are important. By attaching an RTK-GNSS receiver to a smartphone, the scanned point cloud can directly carry absolute coordinates in the national coordinate system, enabling easy comparison with design drawings or existing survey coordinates and accurate comparison of data captured at different times.

For example, some smartphone point cloud tools utilize the Geospatial Information Authority of Japan’s reference station network (such as the CLAS signal from the Michibiki satellites), enabling high-precision positioning even in locations without cellular coverage. This makes it possible to obtain stable point clouds with precise positioning in environments that traditionally caused positioning problems. Because of the reliability of high-precision positioning, earthwork calculation results from smartphones can be confidently used on site.

Data sharing via cloud connectivity

Point cloud data and measurement results captured with a smartphone can be further leveraged by integrating with cloud services. Cloud connectivity offers the following advantages.

• Immediate sharing: After scanning, data can be uploaded to the cloud from the smartphone with one tap. Through the internet, it can be instantly shared with the office PC or other stakeholders, allowing on-site measured earthwork volumes to be used immediately for reporting and review. Supervisors or clients in remote locations can receive information in real time, facilitating quick decision-making.

• Automated analysis and viewer: Point cloud processing and analysis can be performed automatically in the cloud, and volume calculations and cross-sections can be generated quickly. Users can review results in a web browser without operating advanced software. With no need for a high-performance workstation or specialized software, anyone can open a URL to view and measure 3D point clouds in some services.

• Data storage and reuse: Data stored in the cloud are securely preserved and can be retrieved as needed. By managing as-built data and earthwork measurement histories over the long term, the data serve as a “time capsule of the site” useful for later verification and comparison. Compared with paper documents or local PCs, the risk of loss is lower and data can be accessed from anywhere within the organization.

• Integration with other systems: Through the cloud, point cloud data can be overlaid with CAD drawings or BIM models or exported in report formats. Services that automatically generate as-built inspection reports from point clouds are emerging, enabling consistent data utilization in the cloud.

With cloud integration, site data won’t remain buried on an individual’s PC; the organization can share its value. Information flowing from site to cloud and from cloud to office enables collaboration that transcends the boundaries between field and office.

Use cases on civil engineering construction sites

Let’s look at concrete scenarios where smartphone point cloud scanning is used. First, applications to earthwork management on typical civil engineering construction sites.

In road construction or river works, accurately managing the volumes of excavated and backfilled material is important for schedule and cost control. On one site, progress measurement that had previously been done about once a week was changed to an operation where the site manager scans the excavation areas with a smartphone at the end of each day. With just about five minutes of scanning, the day’s excavation and embankment volumes could be quantified and immediately reflected in daily reports and progress documents. The volumes automatically calculated from point clouds matched the recorded number of dump trucks almost exactly, capturing site performance with high reliability.

This enabled quantitative progress management based on data rather than vague impressions like “it looks about X% complete.” Replanning earthwork or arranging machinery for the next day could be decided accurately based on measured data. As a result, unnecessary equipment idle time and material ordering mistakes were reduced and overall project efficiency improved. On some sites, people say they were skeptical at first but now feel uneasy if they don’t scan every day—smartphone earthwork measurement has become routine.

Use cases on land development sites

In residential and land development, large-scale cutting and filling occur. Smartphone point cloud surveying is also powerful at these sites.

During development, it is necessary to constantly check differences between planned and actual earthwork volumes. For example, if excavation has progressed too far, a backfill plan may need to be revised early; conversely, if embankment appears to be short, additional material should be arranged. By periodically scanning the entire site with a smartphone and overlaying the generated terrain model with design data, differences between design and actual conditions become clear at a glance. Tools in use today can color-code point cloud data to show deviations from the design surface, making high and low areas immediately obvious.

On one development site, as-built conditions were recorded with smartphone point cloud surveying at the completion of each phase, and differences from the design quantities were checked continuously. Shortages and excesses that used to be discovered only at intermediate inspections were now identified in real time, minimizing rework and material waste. At project completion, the point cloud data themselves served as the digital record of the finished form and were used for future maintenance and handover documents.

Use cases for disaster survey and recovery

In emergencies such as landslides or earthquakes, smartphone point cloud scanning is extremely useful. At disaster sites, it is crucial to quickly grasp the full extent of damage and plan recovery operations.

For example, at a large landslide site, promptly estimating the volume of displaced material determines the required number of machines and dump trucks and the response policy. At one heavy-rain disaster, local government staff used drones immediately after the event to conduct wide-area photogrammetry, create point cloud models of the collapsed slopes, and calculate volumes. Nearer the ground, detailed point cloud scans with smartphones recorded the collapse details, and combining both datasets enabled three-dimensional analysis of the damage. This allowed the scale of damage—which was difficult to appreciate from plan views alone—to be objectively demonstrated with data, greatly aiding selection of recovery methods.

In another case during the 2023 earthquake disaster, a local contractor that happened to have smartphone point cloud equipment scanned affected sites with a smartphone and immediately shared point clouds and photos with relevant agencies. Even in mountain areas without cellular coverage, high-precision positioning could be obtained using augmentation signals from satellites, allowing accurate records of severed roads. These data helped in planning recovery work and damage assessment, speeding initial response.

Thus, simple point cloud surveying using smartphones and drones becomes a powerful tool for site documentation and reporting in emergencies. Where traditional visual inspection or manual surveying could only cover limited areas, digital technology now provides wide-area, detailed information in a short time. The obtained data are used from recovery planning through later verification, greatly supporting disaster response.

Smartphone simple surveying enabled by LRTK

As described above, tools that allow point cloud scanning with a smartphone and onsite volume calculation produce revolutionary effects in many situations. One product that enables such smartphone simple surveying is LRTK. LRTK is a solution that turns a smartphone into a centimeter-class surveying instrument (cm level accuracy (half-inch accuracy)), and consists of a high-precision GNSS terminal, a dedicated app, and cloud services.

LRTK’s feature is that attaching a small RTK-GNSS receiver to a smartphone enables high-precision positioning while point cloud acquisition using the smartphone’s camera can be performed easily by anyone. On site, you hold a smartphone with an LRTK device attached, point the camera, and walk to scan surrounding structures and terrain. The acquired point cloud data are automatically assigned absolute coordinates, and area, distance, and volume measurements are performed in the cloud on the spot. Measurement results can be checked immediately on the smartphone screen, and with one tap they can be saved and shared to the cloud as needed.

LRTK also supports point cloud measurement compliant with the Ministry of Land, Infrastructure, Transport and Tourism’s “as-built management guidelines,” providing quality sufficient to be used as official as-built measurement results. For example, functions tailored to civil engineering needs—such as instantly calculating embankment volume on site and displaying surplus or shortage compared with the design—are included. Volumes on the order of tens of thousands of cubic meters that occur on large sites can be measured by scanning in sections sequentially without problems.

Cloud integration features are also well developed: point clouds and positioning data acquired with LRTK synchronize to a dedicated cloud with the push of a button. With a web viewer that requires no installation, all stakeholders can view 3D data, enabling seamless sharing with clients and designers. There is no need to attach files to emails or exchange USBs, and the ability to connect site and office in real time is a major advantage.

Thus, smartphone simple surveying with LRTK is attracting attention as a solution that combines “high precision,” “ease of use,” and “cloud connectivity.” As a new everyday tool that anyone on site can use, it is transforming civil engineering and surveying practice. If you have challenges with on-site volume calculations, consider smartphone surveying using LRTK. Cutting-edge technology can dramatically improve your site’s productivity and safety.

FAQ

Q: How accurate is point cloud scanning with a smartphone?

A: By combining a dedicated RTK-GNSS receiver, horizontal and vertical accuracy on the order of a few centimeters (a few in) can be achieved. This is sufficient for most typical construction as-built checks and volume calculations, and measurements can conform to national standards.

Q: Can it be used without special knowledge or qualifications?

A: Yes. Smartphone point cloud surveying is designed for intuitive app operation. Complex equipment settings and surveying calculations are automated, so people without surveying expertise can use it easily. Many staff can begin using it after brief on-site training.

Q: How long does measurement take?

A: It depends on the target and area, but for example, measuring an embankment 30 m (98.4 ft) square can take just a few minutes of walking with a smartphone to obtain point cloud data. Since volume calculations are also processed automatically in the cloud, you can get results in under about 10 minutes in total.

Q: You mention the cloud—what if there is no network at the site?

A: In the case of LRTK, correction signals from the Michibiki satellites can be used, so positioning is possible even where cellular signals are absent. Cloud synchronization of data can be done after moving to an area with reception. Alternatively, data can be stored on the device offline and uploaded later in batch.

Q: Compared to drone surveying, what are the advantages of smartphone surveying?

A: Drones are advantageous for surveying wide areas quickly, but they have constraints such as flight restrictions, weather, and operator skill. Smartphone surveying is more maneuverable and can be used indoors or under structures, which is an advantage. Because it is easy to use daily, smartphone surveying is better suited for fine measurements and frequent progress monitoring that don’t warrant flying a drone. Using both appropriately enables a more efficient site surveying strategy.