How Cross-Section Creation Is Changing – The Latest LRTK Solutions Supporting On-Site DX

The method of creating “cross-sections,” indispensable in surveying and construction sites, is being dramatically transformed by digital technology. Tasks that once required many personnel and long hours are now being significantly streamlined and enhanced by the advancement of on-site DX (digital transformation). This article reviews the need for cross-sections and the challenges of traditional methods, then introduces how the latest solution, LRTK, addresses those challenges. We explain in detail the surprising way LRTK—leveraging a smartphone and high-precision RTK positioning—enables you to capture on-site cross-sections “with a smartphone, by one person.”

Why cross-sections are necessary and the problems with traditional methods

In civil engineering and construction, cross-sections are frequently used to understand the condition of structures and terrain such as roads, embankments, and slopes. A cross-section is a drawing that shows the shape of the terrain or structure when vertically sliced at a certain location, and it is an indispensable deliverable for as-built management, checking deviations from design, earthwork volume calculations, and more. For example, in road construction, final checks are done by measuring pavement and subgrade heights and thicknesses at specified locations and compiling them into cross-sections to verify conformity to design. While creating cross-sections is fundamental to quality control and as-built verification, traditional methods have several issues.

With traditional cross-section creation methods, experienced surveyors or site technicians use surveying equipment to measure heights and widths point by point on site and connect those points to draw cross-sections. Specifically, measuring tapes, staffs (level rods), levels (optical surveying instruments), or total stations are used to determine the elevations of points along the cross-section line, and those data are then drafted. The following issues have been pointed out with this approach:

• High labor and time burden: On-site cross-section measurement typically requires two or more people (a measurer and an assistant), and setting up, moving equipment, and reading leveling measurements are time-consuming. When measuring multiple cross-sections, crews must repeat the work at different positions, resulting in long total working hours. There is also office work to compile measurements into drawings after surveying, which places a heavy burden on site personnel.

• Safety risks: Depending on the measurement location, work can be dangerous—for example, on steep slopes or beside busy roads. Because people must physically enter the measurement area, there is a risk of falls or collapses on high or unstable slopes, and a risk of collisions with vehicles on roads.

• Limited measurement points and the risk of oversight: Manual cross-section measurement is physically limited in the number of points that can be obtained. Only representative points on the cross-section are typically measured and used for drafting, so fine irregularities or localized deviations from design can be missed. Particularly for long sections or large structures, the traditional “measuring only at points” approach can be insufficient for understanding the overall cross-section shape.

• Possibility of human error: On busy sites, human mistakes such as recording errors or forgetting to take photos are common. For example, if the cross-section is not recorded before buried utilities are backfilled, it becomes impossible to verify afterward. Missing data or transcription errors lead to inaccurate cross-sections and cause rework or setbacks.

As described above, traditional cross-section creation faces challenges in terms of equipment and personnel burden, safety, and accuracy/coverage, and the field has increasingly demanded more efficient and reliable methods.

High-precision, easy cross-section data acquisition enabled by LRTK

In recent years, LRTK has attracted attention as a new solution to the problems of cross-section creation. LRTK (El-Arr-Tee-Kay) is a system composed of a small RTK-GNSS receiver that attaches to a smartphone and a dedicated app, turning a smartphone into a high-precision surveying device. RTK stands for “Real Time Kinematic,” a technique that corrects satellite positioning errors (such as GPS) in real time to achieve centimeter-level positioning accuracy. By attaching an LRTK device to a smartphone (e.g., an iPhone) and connecting to a network-based RTK correction service, you can measure positions with an accuracy of several cm (a few in) using just a smartphone, without expensive dedicated surveying equipment.

Using LRTK dramatically streamlines the acquisition of the terrain data that form the basis of cross-sections. By scanning the surroundings with the smartphone’s built-in LiDAR scanner (light detection and ranging sensor) or camera while combining the high-precision positioning obtained from the LRTK receiver in real time, you can collect the surrounding terrain and structures as point cloud data. A point cloud is a collection of countless points that records the shape of the site in three dimensions, with each point containing XYZ coordinates (east-west, north-south, elevation). In LRTK, each point in the acquired point cloud is assigned an accurate coordinate in a global geodetic coordinate system, so scanning alone records the site’s 3D shape aligned with actual survey coordinates. This eliminates the cumbersome conversion to surveying coordinates and alignment work, allowing you to obtain high-precision cross-section data on the spot.

This high-precision mobile scanning allows cross-section data that once required multiple people to be acquired by one person in a short time. Because all you need is a compact LRTK device weighing a few hundred grams and a smartphone, there is no need to transport total stations or heavy equipment, greatly improving mobility. In some cases, dangerous slopes can be measured from a distance with LiDAR without sending personnel up the slope, offering substantial safety benefits. Even without advanced surveying skills, anyone can operate the system by following the smartphone app guidance, making it easy to adopt even on sites facing workforce shortages. An era has begun in which LRTK enables easy acquisition of cross-section data “with a smartphone, by one person.”

Record the entire site with point cloud scans and extract any cross-section later

With mobile scanning using LRTK, instead of measuring only points along a cross-section as before, you can record the site as a whole in 3D point cloud data. An operator holding a smartphone and walking around the site while performing LiDAR scans will capture high-density point clouds of the surrounding 360-degree terrain and structures. This yields a detailed 3D model that is essentially a digital copy of the entire site in a single measurement.

From this point cloud data, you can later cut out (extract) cross-sections at arbitrary positions. For example, slicing the point cloud along a vertical plane defined by two chosen points will display the cross-section shape. Traditionally, sites were planned with specified intervals—“measure cross-sections every X m”—and measured on site each time, but if you have the point cloud, you can freely generate cross-sections later at any required location. This avoids the need for re-surveying due to missed measurements and allows flexible follow-up, such as generating more detailed cross-sections where deviations from the design are found.

Furthermore, point clouds have many uses beyond cross-section creation. Viewing the acquired 3D data allows an intuitive grasp of overall terrain changes and structure shapes, and measuring dimensions other than cross-sections (such as distances, areas, and volumes) becomes easy. In other words, there is a shift from “measuring to create cross-sections” to “digitally recording the site in 3D and creating as many cross-sections as needed.” By digitally capturing the site information comprehensively through point cloud scans, the flexibility and accuracy of cross-section creation are greatly enhanced.

Cross-section display and DXF export in the cloud: faster drawing production

With LRTK, not only can point cloud and positioning data be checked on site, but they can also be uploaded to and utilized in the cloud. With one tap from a smartphone after measurement, data can be synced to the cloud, allowing office PCs to immediately view and analyze the site’s 3D data. Particularly convenient is the cloud-based cross-section display feature. You can slice the uploaded point cloud at any cross-section in a browser, enabling verification of required cross-sections without being on site.

Cross-sections displayed in the cloud can also be exported in DXF format, which can be used directly in CAD software. While civil surveying deliverables often require flat drawings or cross-sections on paper or PDF, using LRTK you can output cross-section shapes automatically generated from point clouds as DXF files and use them in drawing production. This makes producing deliverables far faster and more accurate than manually drafting drawings from measured points. Because the point cloud already contains absolute coordinates, the exported cross-sections are faithfully represented in the public coordinate system, and they can be used directly in downstream CAD editing and quantity calculations.

LRTK’s cloud also includes data-sharing features. Created cross-sections and point cloud models can be easily shared via URL, so stakeholders who do not have dedicated software can view 3D data and cross-sections through a browser. For example, when you want a client or supervisor to check current cross-section shapes, they can access the cloud data to view realistic 3D views and cross-section drawings. This eliminates the need to send drawings by email or have people come to the site, improving communication efficiency.

In this way, LRTK’s cloud integration enables one-stop handling from cross-section creation to sharing and utilization. Data collected on site can be turned into drawings in the cloud the same day, shared with stakeholders, and used for consensus building and next-step construction planning—realizing a fast workflow.

Example use cases where cross-section data is valuable across many sites

LRTK’s high-precision cross-section creation solution is useful across a wide range of site scenarios. Representative use cases include:

• Steep slope and slope face management: On mountainsides or slopes beside roads, regular cross-section measurements are used to evaluate stability and check for signs of collapse. LRTK allows scanning the entire slope from a safe distance and extracting arbitrary longitudinal cross-sections, enabling detailed shape assessment without personnel entering hazardous areas. Cross-sections allow accurate assessment of slopes and deformations, aiding repair planning.

• As-built verification of embankment and cut works: For earthworks in roads or land development, it is necessary to verify that the finished shape matches the design. Traditionally heights and widths were measured at key points to create cross-sections, but if the post-construction terrain is point-clouded with LRTK, shapes along design cross-section lines can be compared instantly. From cross-sections you can calculate excess or deficiency of fill or cut volumes, preventing rework and assisting earthwork quantity control.

• Inspection and shape verification of structures: Cross-sections are also used to check completed shapes of structures such as bridges, tunnels, dams, and retaining walls. For example, measuring tunnel internal cross-sections to verify design radius or comparing concrete structure as-built conditions to drawings. LRTK point cloud scans capture 3D models including fine surface irregularities, enabling accurate cross-sections even for complex shapes. Rebars and piping may also appear in the point cloud, allowing checks of lining thickness or the positions of buried items.

• Pavement thickness and drainage slope checks for roads: In road works, checking cross-slope (crossfall) and pavement thickness is important. Scanning a road with LRTK lets you create longitudinal and transverse cross-sections at arbitrary positions to visualize pavement thickness in sections. You can inspect pavement thickness right after completion to confirm required thicknesses are met. Drainage gradients can also be checked by measuring angles from cross-sections to ensure proper water drainage.

• Disaster site recovery planning: After landslides or slope failures, it is necessary to understand the terrain of the damaged area to plan restoration methods. LRTK enables rapid point cloud measurement of affected areas, allowing creation of cross-sections comparing pre- and post-collapse terrain to assess damage extent and aid temporary road planning. It is also advantageous for safety because data can be acquired without personnel spending long periods in areas at risk of secondary disasters.

• Earth volume management for residential development and foundation works: On housing development sites, cut and fill are used to adjust ground levels, and LRTK is effective for managing earth volumes and as-built verification. Scanning land before and after development allows cross-sections to be created at any time to compare with design ground surfaces. Detailed slope shapes near property boundaries can be captured to check impacts on neighboring land and to inform retaining wall planning. In foundation works, scanning excavation cross-sections after mass excavation allows verification that depth and slopes match instructions.

In these and many other site types, the new workflow for cross-section creation is being utilized. The common advantages across cases are that you can quickly obtain accurate cross-section data on site and immediately turn it into drawings and share them. This speed and precision were not possible before and can significantly raise the quality of site management.

How digitization changes surveying workflows: fewer personnel, faster work, better quality

Introducing LRTK dramatically changes surveying and measurement workflows, including cross-section creation. First, fewer personnel: as mentioned, a single person can complete terrain measurement by walking with a smartphone, so tasks that previously required two to three people can be done alone. This reduces labor costs and the burden of staffing coordination, and allows site management to be handled with a small team, alleviating workforce shortages.

Next, speed-up (reduced working time): once a high-density point cloud is captured, cross-sections can be generated repeatedly later, eliminating the need to re-measure the site whenever a new cross-section is required. Traditionally, after field surveying, teams returned to the office to draft and calculate, often taking days to produce results. With LRTK it is possible to turn site data into drawings via the cloud and obtain results the same day. For example, cross-section data scanned in the morning can be shared with design personnel by noon, and corrective construction can begin in the afternoon—enabling a rapid PDCA cycle. This can shorten construction time and improve responsiveness.

Additionally, quality improvement: point cloud measurement covers far more points than manual measurement, making it less likely to miss as-built variability or local defects. Measurement coverage increases dramatically, improving the accuracy and reliability of cross-sections. Because data are automatically digitized, human errors such as recording mistakes or omissions are also reduced. Continuously storing up-to-date site data digitally makes it an asset useful for historical comparison and future maintenance planning.

Thus, with on-site DX centered on LRTK, you can perform surveying and drawing creation “with fewer people, faster, and more reliably.” The digital workflow not only reduces workload but directly enhances construction management accuracy by providing rich data that traditional methods could not. On-site DX is a prime example of how efficiency gains also lead to improved quality control.

Complete with one smartphone and one person: an easy-to-start LRTK solution

A key strength of LRTK is that its high functionality is very easy to introduce and operate. With just a smartphone and a small device, no special equipment is required, and the intuitive smartphone app keeps the learning curve low, enabling smooth adoption on site. By simply attaching an LRTK receiver weighing only a few hundred grams to a smartphone, a person can start point-cloud surveying as soon as tomorrow.

This “do it with a smartphone, by one person” simplicity greatly enhances site responsiveness. Survey tasks that previously required specialist contractors or in-house survey teams can be performed immediately by the site personnel themselves if equipped with LRTK. When you urgently need to confirm a cross-section or inspect an as-built shape on the spot, you can take out your smartphone and scan right away. Reduced waiting times and the ability to make real-time site decisions directly contribute to construction efficiency and safety.

The low barrier to entry is also attractive. Purchasing a high-performance 3D laser scanner or surveying instrument traditionally required an investment of hundreds of thousands of dollars and operator training, but LRTK allows you to start relatively low-cost and with simple operation. Technicians already familiar with smartphones can use it without difficulty. While basic surveying knowledge is of course necessary, the LRTK app includes measurement procedure guidance and automatic calculation functions so that even non-specialists can achieve a certain level of surveying and drawing accuracy. As a “DX tool anyone can use,” LRTK strongly supports site digitization.

Conclusion: LRTK is changing the norms of cross-section creation

The way cross-sections are created is clearly beginning to change with the advent of LRTK. Measurement work that once required significant effort and personnel can now be completed in a short time with a single smartphone, producing high-precision cross-sections on site. Equipment burdens and safety concerns are greatly reduced, while data coverage and accuracy have dramatically improved.

By adopting LRTK, the latest solution supporting on-site DX, you can resolve traditional problems related to cross-section creation and simultaneously enhance the efficiency and quality of construction management. Digital technology is reshaping the “ordinary” of the site, achieving both productivity gains and strengthened safety management. If you currently face challenges in reducing surveying labor or as-built management, please visit [LRTK official site](https://www.lrtk.lefixea.com/lrtk-phone). The next-generation cross-section creation solution that leverages smartphones will surely contribute to advancing your on-site DX.