RTK Cross-Sections You Can Do Alone! How RTK Cross-Sections Are Changing Field Surveying Norms

Table of Contents

• Importance of creating cross-sections and traditional challenges

• How RTK technology changes cross-section surveying (What is LRTK?)

• High-precision cross-section data acquisition by one person using a smartphone

• Freely create cross-sections from point cloud data

• Streamlined drawing creation and sharing using the cloud

• Use cases for RTK cross-sections: powerful in many field situations

• Benefits: fewer personnel, faster work, improved accuracy

• Next-generation surveying solutions that are easy to adopt

• Conclusion: RTK cross-sections are changing field surveying norms

• FAQ

The method for creating cross-sections—an indispensable deliverable on civil engineering and construction sites—has dramatically evolved thanks to recent digital technologies. Field surveying, which formerly required multiple people and significant time and effort, has entered an era in which high-precision work can be done by a single person using the latest RTK (Real-Time Kinematic) technology. This article reviews why cross-sections are necessary and the challenges of traditional methods, then explains how the latest solutions that combine smartphones and RTK devices realize efficiency and labor savings. We also introduce concrete use cases and the benefits of the new technology, and finally present an easy surveying solution using LRTK.

Importance of creating cross-sections and traditional challenges

On civil and construction sites, cross-sections are frequently used to understand the condition of various structures and terrain such as roads, embankments, and slopes. A cross-section is a drawing that shows the shape of the terrain or structure cut vertically at a given location, and it is an essential deliverable for as-built control (verifying post-construction shape), checking deviations from design, and earthwork volume calculations. For example, in road construction, measuring the pavement and subgrade height at specified locations after completion and compiling them as cross-sections allows verification of whether construction was performed according to design. While cross-sections are fundamental to quality control and as-built verification, creating cross-sections via traditional field surveying has posed several challenges.

Significant manpower and time burden – Traditionally, experienced surveyors used staff rods, optical levels, or total stations and measured each point on site with two or more people, then connected those points to create cross-sections. Setting up and relocating equipment and reading level measurements took time, and when measuring multiple cross-sections, positions had to be changed repeatedly. After measurement there was also clerical work to organize data and create drawings, requiring considerable overall effort and time.

Safety risks – Some measurement locations involve hazardous work. On steep slopes or along busy roads, surveyors entering the site to measure could face risks of falls or traffic accidents. Surveying on unstable slopes was particularly hazardous, requiring careful safety measures.

Limitations in measurement points and overlooked details – Manual cross-section measurement limits the number of obtainable points, so typically only representative points along the cross-section line are measured and plotted. This can miss fine irregularities or localized unevenness (areas deviating from design) between measured points. For long sections or large structures, the sparse continuity of points makes it difficult to fully grasp the entire cross-sectional shape, posing reliability concerns for quality control.

Human error – On busy sites, human errors such as transcription mistakes or missed records are common. For example, if cross-section conditions are not recorded before backfilling buried utilities, they cannot be checked after completion. If measurement points are recorded incorrectly, accurate cross-sections cannot be produced, leading to rework or re-surveying.

As described above, traditional cross-section creation faced challenges in terms of manpower and time burden, safety, and accuracy and coverage, creating a need for more efficient and reliable methods on site.

How RTK technology changes cross-section surveying (What is LRTK?)

One promising approach to address these challenges is the use of RTK (Real-Time Kinematic) technology. RTK is a high-precision positioning technique that applies correction information to satellite positioning data such as GPS, reducing real-time positioning errors to the order of a few centimeters (cm level accuracy (half-inch accuracy)). Recently, solutions that make RTK easily usable with smartphones have appeared; these solutions are called LRTK. LRTK consists of a compact RTK-GNSS receiver that can be attached to a smartphone and a dedicated app, turning a smartphone into a versatile surveying instrument. Without expensive dedicated surveying equipment, a smartphone with an LRTK device can achieve positioning via network RTK correction services with an accuracy of a few centimeters (cm level accuracy (half-inch accuracy)).

High-precision cross-section data acquisition by one person using a smartphone

Using LRTK dramatically improves the efficiency of acquiring terrain data for cross-section creation. What used to require multiple people measuring each point on site can now be completed in a short time with just a smartphone and a small device. By scanning the surroundings with a smartphone’s built-in LiDAR scanner (distance measurement by light) or camera while combining the high-precision position coordinates obtained from the LRTK receiver in real time, you can create 3D data of the surrounding terrain and structures on the spot. The resulting point cloud data—a collection of many measurement points—has accurate XYZ coordinates (in the World Geodetic System) attached to each point, so simply walking the site and scanning records the shape in the survey coordinate system faithfully. Time-consuming transformations to reference points or post-processing alignment are unnecessary, enabling immediate acquisition of high-precision cross-section data.

This high-precision mobile scanning allows cross-section measurements that previously required several people and long hours to be completed by one person. Because only a compact LRTK device weighing a few hundred grams and a smartphone are needed, there is no need to carry a total station or heavy tripod, greatly enhancing field mobility. On slopes, if LiDAR scanning can be done from a safe distant position, there is no need to enter hazardous areas, offering significant safety advantages. Operation simply follows prompts in the smartphone app, so no special expertise is required; anyone can use it as an easy surveying tool, making it suitable for sites facing labor shortages. Indeed, LRTK has ushered in an era in which cross-section data can be easily acquired “with a smartphone, by one person.”

Freely create cross-sections from point cloud data

With mobile scanning using LRTK, there is no need to decide cross-section lines in advance as with traditional methods. Because the entire site can be recorded as a 3D point cloud, a “digital copy” of the whole field can be captured in a single measurement. If an operator walks around the site holding a smartphone, the terrain and structures around them are captured as a high-density point cloud covering 360 degrees. A major advantage is that cross-sections can be generated later at arbitrary positions from this acquired data. For example, slicing the acquired point cloud with a “vertical plane that connects any two points” displays the cross-sectional shape cut by that plane. Traditionally, one would plan to measure cross-sections every XX m (XX ft), but with a point cloud you can create any required cross-section later.

This prevents additional surveys or rework due to missed measurements and allows detailed verification of locations where discrepancies between design drawings and as-built conditions are found. Even if the number of desired cross-sections increases, there is no need to revisit the site as long as the data exists; you can respond flexibly. Also, once acquired, point cloud data can be used for many purposes besides creating cross-sections. Viewing a 3D model makes it easy to intuitively understand overall terrain changes and structure shapes, and measuring distances, areas, and volumes becomes straightforward. This approach transforms the mindset from “measure points to create cross-sections” to “digitally record the site and extract cross-sections as needed.” By capturing site information exhaustively in a point cloud, the freedom and reliability of cross-section creation improve dramatically.

Streamlined drawing creation and sharing using the cloud

With LRTK you can not only check point cloud data and position information on site but also upload and utilize the data in the cloud. After measurement, a one-tap cloud sync from the smartphone allows office PCs to immediately view and analyze the site’s 3D data. Particularly convenient is the cloud-based cross-section display function. On the uploaded point cloud model, specifying any cross-section position in the browser displays the cross-section on the spot. Even if you are not on site, as long as the data is shared, you can check required cross-sectional shapes anytime.

Furthermore, cross-sections displayed in the cloud can be exported in DXF format, which CAD software can handle. While civil surveying deliverables are typically required as paper or PDF plans and cross-sections, LRTK can automatically generate cross-section lines from the acquired point cloud and export them as DXF data for drawing creation. This produces deliverables far more quickly and accurately than manually drafting drawings based on measured points. Because point cloud data already contains absolute coordinates in a public coordinate system (the World Geodetic System), exported cross-sections preserve accurate spatial relationships and can be used directly in downstream CAD editing or quantity calculations.

Cloud sync also offers the advantage of data sharing. Generated cross-sections and 3D point cloud models can be easily shared via a URL, so clients or managers without specialized software can check the current 3D view or cross-section in a browser. This saves the hassle of emailing drawing files or asking stakeholders to visit the site, enabling near-real-time information sharing and decision-making. LRTK’s cloud integration allows the entire workflow from acquisition to drawing creation and utilization to be completed in one place, enabling same-day cloud-based drawing generation and sharing of site data to drive subsequent actions in a speedy workflow.

Use cases for RTK cross-sections: powerful in many field situations

High-precision cross-section creation with LRTK is useful in a wide variety of field situations. Here are some representative use cases.

• Monitoring steep slopes and cut/fill faces – On steep mountainsides and roadside slopes, cross-section measurements are taken periodically to monitor ground stability and deformation. LRTK allows scanning the entire slope from a safe distant position and extracting arbitrary longitudinal or transverse sections, enabling detailed shape assessment without personnel entering hazardous areas. Cross-sections can accurately capture changes in gradient or abnormalities and support early repair planning.

• As-built verification of fills and cuts – For roadworks and land development, it is necessary to check whether completed fills and cuts match design. Traditionally, heights and widths at key locations were measured and drawn as cross-sections, but with LRTK you can point-cloud the entire post-construction terrain and instantly compare current shapes to design cross-section lines. Calculating excess or shortage of fill/cut volumes from cross-sections becomes easy, helping prevent rework and improving earthwork volume management.

• Structural shape inspection – Large structures like tunnels, bridges, dams, and retaining walls are often checked after completion by measuring cross-sections and comparing them to design values. For example, measuring tunnel cross-sectional clearance to verify excavation radii or checking thicknesses of bridge members. LRTK point cloud measurement yields high-resolution 3D models including fine surface irregularities, enabling accurate cross-section generation even for complex shapes. If rebar or piping appears in the point cloud, it can be used to check lining concrete thickness or equipment placement.

• Checking pavement thickness and drainage slopes on roads – In road works, inspecting pavement thickness and transverse slope (cross-slope) is important. If the road is scanned with LRTK, vertical and cross sections can be made at any location to check pavement thickness on drawings. Immediate on-site inspection of pavement thickness after construction is possible to confirm that specified thicknesses are met. Measuring cross-section slope angles from cross-sections allows checking that proper drainage slope is provided.

• Disaster site recovery planning – After landslides or slope failures, it is necessary to assess the collapsed terrain and plan restoration methods. With LRTK you can scan affected areas quickly and create cross-sections comparing pre- and post-collapse terrain data (if pre-disaster data is available) to evaluate the damage scale. Cross-sections are also useful for planning temporary road routes. Even in situations with risk of secondary hazards, stakeholders can acquire necessary data without staying long on site, improving safety.

• Earthwork management for residential development and foundation work – In residential development, land regrading involves cut-and-fill adjustments; LRTK helps verify as-built shape and manage earthwork volumes. By point-cloud surveying before and after development, design comparisons including slope shapes near site boundaries become straightforward. It provides material for evaluating impacts on neighboring properties and for retaining wall design. Likewise, scanning the ground surface after foundation excavation lets you verify excavation depth and slopes against instructions using cross-sections.

As shown above, the ability to acquire and draw cross-section data quickly and with high precision brings great value to field work across scenarios. Common benefits are the speed of obtaining necessary cross-section data and sharing it with stakeholders, along with high accuracy. With unprecedented speed and coverage, site conditions can be understood more comprehensively, greatly improving construction management quality and safety.

Benefits: fewer personnel, faster work, improved accuracy

The new cross-section creation workflow enabled by RTK and digital technology refreshes traditional methods with three key advantages: fewer personnel, reduced work time, and improved quality.

• Fewer personnel – Since one person can complete terrain surveying by walking with a smartphone, tasks that previously required 2–3 people can now be done solo. This reduces labor costs, simplifies personnel coordination, and allows limited staff to cover more sites. In the construction industry facing severe labor shortages, labor-saving in field surveying is a pressing issue, and LRTK can be a key solution.

• Faster work – Once a high-density point cloud is acquired, cross-sections can be generated repeatedly later, eliminating the need for re-surveying whenever required. Traditionally, it could take days from surveying to office drafting and quantity calculation, but with LRTK you can produce drawings in the cloud on the same day as measurement. You could scan in the morning, share data with design staff by noon, and start corrective work in the afternoon—making a rapid PDCA cycle realistic. This enables schedule compression and faster site responsiveness.

• Improved accuracy – Point cloud measurement yields far denser data than manual surveying, making it easier to capture slight variations and localized defects in as-built conditions. Dramatically improved data coverage enhances cross-section accuracy and reliability, reducing the risk of rework due to oversight. Automated digital recording of measurements also reduces human errors such as transcription mistakes and omissions. Accumulated 3D data becomes a valuable asset for tracking terrain changes over time and for future maintenance management.

Thus, site DX (digital transformation) centered on LRTK enables surveying and drawing creation with fewer people, more quickly, and more reliably. Beyond mere efficiency gains, the abundance of data obtainable with this approach fundamentally raises the quality of construction management. It is an exemplary case of using digital technology to renew field “common sense,” achieving both higher productivity and better quality and safety.

Next-generation surveying solutions that are easy to adopt

A major advantage of LRTK is that, despite its high functionality, it is easy to introduce and operate. All you need is a smartphone (e.g., iPhone) and a pocket-sized LRTK receiver—no large specialized equipment is required. The intuitive smartphone app is easy to learn, facilitating smooth on-site adoption. By simply attaching an LRTK weighing only a few hundred grams to a smartphone, a single person can start high-precision 3D surveying as soon as tomorrow.

This “single smartphone, single-person completion” ease greatly enhances site responsiveness. Surveying tasks that previously required arranging specialized surveyors or an in-house survey team can now be carried out immediately by site personnel. When you need to quickly check a cross-section or inspect as-built conditions, you can take out your smartphone and scan immediately. Reducing wait times and enabling immediate decisions directly improves construction efficiency and safety.

Low cost and low barriers to adoption are also attractive. Introducing high-performance 3D laser scanners or surveying instruments requires large investments and operator training, but LRTK can be started at relatively low cost and is not difficult to operate. Technicians familiar with smartphones can use it without resistance. While basic surveying knowledge is of course necessary, LRTK apps include guided measurement procedures and automated calculation features, enabling non-specialists to perform surveying and drafting with a certain level of accuracy. As an “easy-to-use site DX tool,” LRTK strongly supports digitalization on the job site.

Conclusion: RTK cross-sections are changing field surveying norms

The field of cross-section creation is unmistakably changing thanks to RTK technology and smartphone utilization. What once required many people and much time can now be completed quickly with a smartphone, enabling high-precision cross-sections on the spot. The burden of transporting equipment and the risks of working in hazardous locations are greatly reduced, while data coverage and accuracy have dramatically improved.

By using the latest solution LRTK, traditional problems related to cross-section creation can be resolved, simultaneously enhancing the efficiency and quality of construction management. Digital technology is rewriting on-site “common sense,” enabling both productivity gains and strengthened safety management. If you currently face challenges with manpower or time in surveying or as-built control, consider LRTK-based easy surveying. The next-generation cross-section creation solution using smartphones will surely contribute to your site DX initiatives.

FAQ

Q: What is RTK? Can it be used with a smartphone? A: RTK (Real-Time Kinematic) is a technique that applies correction information to satellite positioning data (such as GPS) to dramatically improve positioning accuracy. Ordinary GPS has errors on the order of meters, but RTK can achieve high-precision positioning with errors on the order of a few centimeters (cm level accuracy (half-inch accuracy)). Recently, small RTK receivers that attach to smartphones and enable easy RTK positioning (for example, LRTK) have emerged, allowing smartphones to benefit from RTK without dedicated equipment.

Q: Why does LRTK make single-person surveying possible? A: Traditionally, surveying was commonly done in pairs using a staff and surveying instrument, but with LRTK one person can complete surveying. A smartphone plus an RTK receiver provides high-precision positions while you walk and measure yourself, removing the need for an assistant. Measurement data is automatically recorded in the app, so no second person is needed to take notes. Equipment transport and setup are also minimized, enabling efficient solo surveying.

Q: How are cross-sections created from measured data? A: Data acquired with LRTK is saved as 3D point cloud data. This point cloud is processed in a dedicated app or cloud service, and a vertical cross-section is created by slicing at any chosen position. For example, if you specify a cross-section line on the point cloud, the software automatically generates longitudinal or transverse sections along that line. Cross-section line data can be exported in DXF format and imported into CAD drawings for finishing.

Q: Which traditional surveying instruments can be dispensed with when using LRTK? A: Depending on the application, at least for cross-section surveying the need for traditional levels and total stations may be reduced. A smartphone and LRTK can obtain high-precision horizontal and vertical positions, and LiDAR scanning covers wide areas, so for simple as-built checks you may not need optical surveying instruments or heavy surveying equipment on site. However, when establishing design control points or when very high-precision control is required, specialized surveying instruments and a surveyor’s judgment may still be necessary.

Q: Can LRTK be used where GPS signals don’t reach or indoors? A: RTK-GNSS relies on satellite signals and works best in open-sky locations. In environments where GPS cannot be received—such as inside forests, tunnels, or indoors—RTK positioning does not function. However, LRTK is modular and can be combined with other measurement methods such as drone surveys, photogrammetry, or indoor 360° camera measurements. By choosing the appropriate method for the situation, efficient measurement can be achieved in a wide range of scenarios.