Making Volume Calculation Smart with Point Clouds × Cloud! The Future of Civil Surveying

Table of Contents

• Introduction

• Basics of 3D Surveying and Point Cloud Data

• What Volume Calculation with Point Cloud Data Is

• Benefits of Introducing Point Cloud Surveying

• Possibilities Expanded by Using Cloud Services

• The Future of Civil Surveying

• Simple Surveying with LRTK

• FAQ

Introduction

On construction and civil engineering sites, volume calculation (earthwork quantity estimation) for embankments, excavations, and other earthworks is an essential task for progress and quantity control. Traditionally, survey instruments were used to create cross-sections of the terrain and volumes were calculated using the average end area method. However, this method requires enormous time and effort as the coverage area grows and is prone to errors in accuracy because it estimates from a limited number of survey points. Surveying on steep slopes or in areas with poor footing can also be hazardous.

In recent years, 3D surveying using drones, terrestrial laser scanners, and even smartphone LiDAR has been spreading. If the point cloud data acquired with these technologies is processed using dedicated point cloud viewers or cloud services, volume calculations for earthworks can be performed much faster and more accurately than before. This article explains the basics of what point cloud data is, how to calculate volumes using point clouds, and how cloud utilization streamlines workflows and shapes the future of civil surveying. Finally, we introduce a simple smartphone-based surveying solution, LRTK, that makes it easy to get started.

Basics of 3D Surveying and Point Cloud Data

First, let’s cover the basics of 3D surveying and point cloud data. 3D surveying is a general term for methods that measure site terrain and structures in three dimensions and convert them into digital data. Typical approaches include laser scanning (LiDAR) and photogrammetry. Using LiDAR, laser beams are emitted from tripods or vehicle-mounted devices and the time difference until the beams return is used to obtain the three-dimensional coordinates of many points. A single scan can capture high-density data of several million points or more, allowing terrain and structural shapes to be recorded in detail down to the millimeter (0.04 in) level. Photogrammetry, on the other hand, generates 3D models or point clouds by taking multiple photos of a site with drones or cameras and performing image analysis with specialized software. It can capture wide areas quickly, and recent software advancements have made it easy to create high-accuracy point cloud data. More recently, it has become possible to perform small-scale 3D measurements using just a smartphone by leveraging built-in LiDAR on iPhone or iPad and dedicated apps.

The resulting point cloud data is a collection of countless measured points in space, where each point has three-dimensional position coordinates X, Y, and Z. Points may also include attributes such as color or return intensity. Put simply, a point cloud is a “3D model represented by countless points.” While traditional surveying recorded only tens to a few hundred points, point cloud surveying can acquire millions of points. Because the site is measured with such high density, minute undulations in the terrain and fine surface details of structures can be accurately reproduced. For this reason, point cloud use is encouraged in initiatives like the Ministry of Land, Infrastructure, Transport and Tourism’s i-Construction, and the construction industry is rapidly adopting 3D surveying.

What Volume Calculation with Point Cloud Data Is

So how do you perform volume calculation (earthwork quantity estimation) using point cloud data? Here are the basic methods. There are two typical cases: one is calculating cut and fill volumes from the difference between pre- and post-construction terrain, and the other is calculating the volume of a single embankment or material stockpile.

① Volume calculation by differencing point clouds before and after construction: For example, in road works where the ground is excavated or filled, point cloud data of the ground surface is acquired both before and after construction. By overlaying and comparing the height difference between the two, the volumes of the removed and added portions can be calculated. Whereas traditional cross-section methods estimated earthwork from limited sections, comparing point clouds essentially subtracts two detailed datasets that cover the entire surface, enabling high-precision quantity calculations that reflect even fine surface irregularities. Once point clouds are acquired, it is also easy to specify an arbitrary area in analysis software later and recalculate the volume. If part of the terrain changes due to heavy rain, you can extract only the affected area from existing data and recalculate it, eliminating the need for a full re-survey of the site. Storing point cloud measurement data thus provides flexible quantity calculation as needed.

② Volume calculation for a single embankment or stockpile: On site, embankments or piles of materials (soil, crushed stone, etc.) often form. To calculate the volume of such an individual pile from point cloud data, you set a reference base plane or ground elevation and enclose the target pile within the point cloud viewer. The software automatically captures the surface from the point cloud and computes the volume of the raised portion within the specified area. In the past, this required converting point cloud data into polygon meshes or other surface models to compute volumes, but recent software and cloud services can produce volumes with a single click after uploading point clouds. Even without advanced 3D CAD skills, it is becoming possible to obtain automatic volume calculations simply from point cloud data.

As described above, utilizing point cloud data can greatly automate and simplify volume calculations. However, to obtain high-accuracy results, it is important to standardize surveying references beforehand. When comparing pre- and post-construction point clouds, they must be measured in the same coordinate system to produce accurate differences. For drone photogrammetry, set ground control points (known coordinates on the ground); for laser scanning, perform proper instrument alignment (calibration and registration) so both point clouds overlap without offset. Also, removing unnecessary points outside the area for volume calculation in advance reduces noise-related errors and improves accuracy. If these points are addressed, volume calculation from point clouds can be performed almost automatically and accurately.

Benefits of Introducing Point Cloud Surveying

There are many advantages to using 3D surveying with point cloud data for volume calculation compared with traditional methods. Here are the main benefits.

• High-accuracy quantity estimation: Point clouds capture detailed data comprised of millions of points that cover the entire site, so there are no gaps in the information used for volume calculation. Unlike traditional methods that estimate from a handful of manually measured points, point clouds can compute accurate volumes reflecting small surface undulations and slopes. As a result, progress tracking and quantity reporting become far more reliable. Because the data are objective digital records that yield the same results regardless of who measures them, they are persuasive materials for clients and stakeholders. Additionally, once point cloud data are acquired, it is easy to slice arbitrary cross-sections later and recalculate, reducing the need to revisit the site for additional measurements. This prevents errors from missed measurements and enables consistent high-accuracy quantity control.

• Improved work efficiency and time savings: Introducing point cloud technology dramatically streamlines surveying and volume calculation workflows. Acquiring 3D point clouds covers wide areas much faster than manual methods. A laser scanner can measure an entire surroundings in a matter of minutes, and a drone can quickly capture large sites from the air. Methods have emerged where simply walking around the site with a smartphone or tablet equipped with LiDAR can acquire surrounding point clouds in a few minutes. Areas that once required survey teams hours to measure dozens of points can now be captured in a single scan. Furthermore, volume computation from acquired point cloud data is automated in software, significantly reducing calculation time. Tasks that once required manual computations or spreadsheets to integrate cross-section areas can now produce immediate results by selecting the area of interest in a point cloud viewer and clicking a button. Because volumes can be determined on site from the acquired data, there is no need to take data back to the office for recalculation. Field reports indicate substantial time savings, such as “surveying finished in less than half the time” or “downtime decreased and tasks could be done in parallel.” Increased productivity across operations can shorten project schedules and allow earlier starts for subsequent phases.

• Labor savings and cost reductions: Improved survey efficiency helps address labor shortages and rising costs. With fewer people required to measure large sites, labor savings can reduce personnel and subcontracting expenses. Tasks that formerly required a specialized survey team spending a full day can, with modern equipment, often be completed by a single operator in a short time. For sites struggling with chronic technician shortages, point cloud technology is a powerful solution that enables accurate surveying with limited staff. Automation of measurement and calculation also reduces human error, preventing costly rework, re-measurements, or additional construction. Because the required accuracy does not depend on individual operator skill, quality variability decreases and the time spent on corrective work declines, leading to overall cost savings. Furthermore, the cost of adopting point cloud technology has fallen significantly in recent years. Where high-priced laser scanners and specialized software were once mandatory, more affordable options using drones or smartphones are now available. For example, combining a compact RTK-GNSS receiver for smartphones (high-accuracy GPS) with a dedicated app can achieve point cloud measurement and volume calculation accuracy comparable to equipment that once cost several million yen. With such price accessibility, even smaller companies can consider one-device-per-person deployment. If every staff member can conduct measurements from their own device, wait times for surveying disappear and site-wide productivity improves directly.

• Increased safety through non-contact measurement: Point cloud measurement is conducted by emitting laser light or taking photographs remotely, so surveyors do not need to enter hazardous areas. Areas that were dangerous for people to access—such as steep slopes or high structures—can be measured safely from a distance. For example, while excavation machinery is operating in a pit or on slopes at risk of collapse, laser scans or photographs from above or from a safe distance can record detailed shapes. Ensuring worker safety is always a top priority, and point cloud technology significantly reduces surveying risk.

• Support for consensus building through shared 3D data: 3D data obtained from point cloud viewers is powerful for post-survey information sharing and stakeholder consensus building. Because point clouds realistically represent the site in three dimensions, site conditions that are difficult to convey with 2D drawings or numerical data alone can be intuitively understood at a glance. For example, showing pre- and post-construction terrain changes with 3D point cloud models, or overlaying planned design lines on point cloud data of the as-built shape, enables visual verification of progress and quantities. When clients and site staff view the same 3D data during discussions, misunderstandings are reduced and communication and consensus building become smoother. Using cloud-based point cloud viewers allows access to the same data from multiple locations via the Internet, enabling real-time sharing with remote stakeholders. By leveraging shared digital data in this way, point cloud measurement becomes more than a mere quantity calculation tool—it has the potential to streamline overall site management.

Possibilities Expanded by Using Cloud Services

In handling point cloud data, the use of cloud services greatly expands convenience and possibilities. Cloud-based point cloud viewers and analysis services eliminate the need to install specialized software and allow handling large point clouds without a high-spec, expensive PC. Uploading vast point cloud data acquired in the field to the cloud lets servers handle heavy processing so your local computer is not burdened. Even when data size reaches several GB, cloud processing is reliable.

Clouds are also effective for shortening processing time. In the past, post-scan processing could take hours, but automation and acceleration of the entire process are now commonplace. For example, in drone photogrammetry, you can aerially capture a wide site in around 15 minutes and upload the photos to a cloud service, which may then generate point cloud models and orthomosaics (top-down photographic maps) within a few hours. With smartphone scans, you can acquire point clouds by walking the site for tens of seconds to a few minutes, and some apps display volume calculation results immediately within the app. Point cloud viewers’ calculation engines have also been optimized so that standard earthwork computations can produce near-real-time results. This is overwhelmingly faster than manual calculation, significantly reducing total work time.

Storing data in the cloud also smooths information sharing. As mentioned earlier, browser-based point cloud viewing services allow you to instantly share the latest scan data with colleagues at the office or other locations. You no longer need to email drawings or have people come to the site; meetings can be held while viewing the same 3D model online, accelerating decision-making. If data is saved in the cloud, comparing with past survey data or monitoring long-term changes is simple. Regularly acquiring point clouds allows you to overlay models from different times on the cloud and track increases or decreases in earthwork volume. In this way, the combination of point clouds × cloud not only speeds up computation but also creates an environment where anyone can use 3D data regardless of location, strongly supporting DX (digital transformation) on site.

The Future of Civil Surveying

Point cloud measurement and cloud utilization are dramatically changing civil surveying on sites today. What was once considered a specialized skill, 3D point cloud work is becoming an everyday tool that site supervisors and construction managers can handle themselves. It is fair to say that a time when “measuring earthworks with point clouds is the norm” is approaching. Public works by national and local governments are also actively introducing point cloud-based quantity management, with 3D as-built management guidelines aligned with i-Construction being established. Quantities calculated from properly captured point clouds are increasingly being accepted for inspection and quantity confirmation. There are already cases where inspections have passed based on quantities measured by point clouds.

With technical standards and operational practices being established, the results of point cloud surveying are expected to become one of the formal recording methods in the future. Of course, conventional surveying methods have their merits, and for the foreseeable future both approaches will likely be used in combination depending on the situation. But it is wise to actively leverage the advantages of new digital measurement. Fully applying high-accuracy 3D data to design and construction management can enhance quality control and streamline construction processes, creating ripple effects beyond surveying. The future of civil surveying is a world where smart measurement and management centered on point clouds and the cloud become standard. As sensors and AI technologies advance, real-time updates to a site’s digital twin for as-built management will become increasingly feasible. An era when the site itself—not just drawings and numbers—is digitized, understood, and shared is approaching.

Simple Surveying with LRTK

As described above, 3D measurement using point cloud viewers brings great benefits to surveying work and is well worth adopting. However, some may hesitate due to concerns such as “Can our company truly use this?” or “We cannot afford expensive equipment.” Here, smartphone-based LRTK simple surveying is worth attention. LRTK is a positioning platform that uses a compact high-precision GNSS receiver integrated with a smartphone; when combined with a smartphone, it enables easy centimeter-level positioning (cm level accuracy (half-inch accuracy)). Its major appeal is that without complicated operations or large initial investments, you can try 3D surveying starting today with your current smartphone and a compact device.

For example, if you acquire point clouds using a smartphone’s built-in LiDAR or a photogrammetry app and augment them with accurate positioning from an LRTK device, you can perform point cloud surveying with accuracy approaching dedicated equipment. Quick on-site measurements and immediate volume calculations are possible even without special skills. If you are interested in volume calculations using point clouds but feel the barrier is high, starting with smartphone surveying using LRTK is recommended. Trying it on your company’s site will let you experience its ease and effectiveness. By making point cloud technology more accessible, LRTK can dramatically improve the accuracy and efficiency of your surveying work.

※For detailed product information or consultation on implementation, please see the [LRTK official site](https://www.lefixea.com). Take advantage of cutting-edge tools to improve on-site productivity.

FAQ

Q1. Can I calculate volumes with point clouds even without drones or expensive 3D scanners? A. Yes, it is possible. High-performance laser scanners and drones are certainly useful for large-scale surveys, but there are ways to leverage point cloud technology without them. For small areas, recent smartphones (e.g., the latest iPhone or iPad with LiDAR) can acquire point cloud data. If high-precision positioning is needed, combining a smartphone GNSS device such as LRTK makes centimeter-level point cloud surveying possible with inexpensive equipment. Photogrammetry—taking photos from the ground with a digital camera and processing them in software—is also effective without using drones. By choosing the optimal method for the site scale and purpose, you can acquire sufficiently practical point cloud data and calculate volumes without costly equipment.

Q2. Is operating a point cloud viewer difficult? Can beginners handle it? A. In recent years, point cloud viewer usability has improved dramatically, and basic viewing and measurement are not too difficult for beginners. Interfaces vary by viewer or service, but many provide intuitive workflows where you move the viewpoint with a mouse and select functions like “distance measurement” or “volume measurement” from menus and click. Cloud-based point cloud viewers are designed to be used without complex settings and require no installation or environment configuration. While advanced analysis requires some training, basic volume calculation can generally be understood after a few tries. Many software and services offer tutorials and support materials, so you can learn by referring to those. It’s smoothest to practice with small sample datasets before working with full-scale site data.

Q3. Can the accuracy of volumes calculated from point clouds be trusted? How do errors compare to traditional surveying? A. Volumes calculated from properly acquired point clouds have been shown to achieve high accuracy comparable to traditional surveying methods. For example, when using point clouds from drone photogrammetry or terrestrial laser scanning, differences from volumes computed by traditional cross-section methods are often within about 1–2%. In other words, results can be nearly identical to carefully conducted traditional surveys. However, ensuring this accuracy requires setting sufficient control points and calibration during surveying and accurately registering multiple point clouds if more than one dataset is collected. Excessive noise or missing data in point clouds can introduce errors, so appropriate post-processing—such as removing unnecessary points—is important. Under proper conditions, point cloud surveying can match conventional survey accuracy and is increasingly recognized publicly. Because it measures wide areas in detail at once, there is less chance of overlooking local features, and overall data reliability may be higher.

Q4. Does calculating volumes from 3D point clouds take a long time? Will I be kept waiting for data processing and computation? A. The time from point cloud generation to volume calculation has been greatly shortened by technological advances. In the past, post-scan processing with specialized software could take many hours, but today automated systems that generate point clouds from drone imagery and apps that provide instant results from smartphone scans have emerged. For instance, drone surveys can capture a wide site in about 15 minutes and, after uploading photos to a cloud service, produce point cloud models and orthomosaics within a few hours. Smartphone scans can acquire point clouds by walking the site for tens of seconds to a few minutes, and some apps display volume results instantly. Point cloud viewers’ computation engines have also been optimized so that typical earthwork calculations return near-real-time results. This is far faster than manual calculations and significantly reduces total work time. If dataset sizes are large, cloud services can handle server-side processing so your PC is not overloaded.

Q5. Will quantities measured and calculated from point clouds be accepted as official as-built quantities? A. Currently, a nationwide unified operational rule is not yet fully established, but point cloud-based quantity management is increasingly being adopted publicly. For national and municipal projects, 3D as-built management guidelines corresponding to i-Construction have been developed, and more cases use quantities calculated from point clouds for inspection and quantity confirmation. However, to be officially accepted, you must follow procedures that prove the reliability of the survey results. For photogrammetry, for example, establish multiple known-coordinate control points on site to verify accuracy; for laser scanning, perform equipment calibration and cross-checks with existing terrain. You may also need to provide explanatory materials on the survey accuracy and calculation methods to owners or supervisors. As technical standards are established, properly conducted point cloud surveys are expected to be recognized as official records and quantity estimation methods. There are already sites where inspections passed based on point cloud-measured quantities, and point cloud reporting is expected to become one of the new standards. While continuing to use traditional methods where appropriate, it is beneficial to actively leverage the advantages of new techniques.