How Slope Greening DX Achieves Construction Efficiency and Quality Improvement

Slope greening works involve applying vegetation to cut or fill slopes to prevent soil erosion and improve landscape aesthetics. These projects are often carried out on steep slopes in mountainous areas or alongside roads, making the work environment harsh and efficient construction difficult. Traditional methods rely heavily on craftsmen’s experience and manual labor, requiring significant manpower and time while producing variable quality. Against this backdrop, expectations are rising for construction DX (digital transformation) as a means to simultaneously improve construction efficiency and ensure quality. In fact, supported by the Ministry of Land, Infrastructure, Transport and Tourism’s *i-Construction* initiative, the use of digital technologies is becoming the new norm in civil engineering. By leveraging the latest 3D surveying technologies, AR (augmented reality), high-precision GNSS positioning, and other digital tools, it is possible to reduce labor, visualize work progress, and minimize errors in slope greening works—dramatically improving construction efficiency and accuracy. This article整理s the challenges faced on slope greening sites and explains key points for improving efficiency and quality through DX adoption. At the end, we introduce LRTK as an example of a solution that digitizes everything from surveying to construction management, offering a starting point for on-site DX.

Site challenges in slope greening works

• Dangerous and inefficient surveying work: Slope surveys on steep faces are performed by workers walking the slope using tape measures and survey rods, which carries risks such as falls. Measuring each point is time- and labor-intensive, making it difficult to grasp large areas of terrain quickly.

• Discrepancies between existing terrain and design: When the site terrain differs from the design drawings, the conventional approach required detailed pre-construction surveys to revise the design. Insufficient survey accuracy or point density can lead to discoveries after completion that the work does not match the design, causing rework. Such discrepancies can also lead to extra repair work or complaints.

• Burden of as-built confirmation and quality control: Verifying that as-built conditions meet design criteria—such as spray thickness and slope gradient—requires numerous measurements and photographic records. Traditionally, site technicians manually measured limited points and handled pass/fail judgments and report creation, which was a large burden. Because measurements were point-based only, there was a risk of overlooking localized defects.

• Labor shortages and skill transfer issues: Slope work relies heavily on veteran specialized skills (rope-based high work, uniform spray application techniques, etc.), but the aging workforce and lack of younger workers are serious problems. Even if more workers were desired, safety considerations often force operations to proceed with a limited crew, increasing demand for labor-saving measures.

• Difficulty in on-site consensus and communication: When sharing the final image or construction process with clients and site stakeholders, drawings and verbal explanations alone can be hard to convey. Since the appearance of slope greening is important, disagreements in perception can lead to time-consuming rework or adjustments.

• Cumbersome record-keeping and reporting: Managing the vast number of photos and measurement data taken at each stage, and creating as-built reports and drawings, was traditionally done using paper logs or spreadsheets and was inefficient. Busy sites often suffer from missed photos or incomplete records; without records, it is impossible to prove quality, which in the worst case can lead to rework or disputes.

Improving construction efficiency and quality through DX adoption

• Labor savings: By using DX technologies, tasks that depended on manual labor can be replaced by machines or digital tools, reducing the required workforce and work hours. For example, introducing automated measurement and data processing can enable surveys and inspections that previously required multiple people to be completed by a small team in a short time.

• Visualization: Visualizing site conditions and design data with 3D models or AR allows intuitive understanding of information that was previously invisible. Projecting the finished image on site or color-coding progress and discrepancies helps all stakeholders share the same understanding, reducing communication loss.

• Error prevention: Digital recording of measurements, automatic calculations, and cloud sharing prevent human recording errors and missed measurements. Sensor-measured data are always objective, suppressing quality defects and rework caused by human error.

• Workflow streamlining: Connecting the entire flow from surveying to design, construction, inspection, and reporting digitally reduces waiting times and redundant work. For example, if data collected on site are immediately analyzed and shared in the cloud, the traditional process of taking data back to the office for drawing and reporting can be shortened. Real-time information sharing speeds decision-making, leading to overall shorter construction periods and cost savings.

• Safety improvement: Labor savings and automation reduce the need for workers to enter hazardous areas. Remote measurement and real-time sharing enhance safety management. For example, surveying and inspection that used to be conducted on the slope can be done from a safe location, directly reducing worker risk.

Capturing terrain area-wise with point cloud scans and linking to design

Among DX technologies, 3D point cloud scanning for terrain measurement is particularly effective. By using laser scanners or drone photogrammetry to acquire 3D data of an entire slope, elevation differences and surface irregularities can be captured as surface data. There is no need to mentally interpolate between distant survey points as with traditional methods; accurate terrain models, contour lines, and cross-sections can be freely generated from the acquired point cloud. This makes coordination with design smoother. For example, importing pre-construction point cloud data into design software allows the creation of realistic, terrain-adapted design plans. Comparing as-built point clouds with the design 3D model makes it possible to verify the finished state at a glance. Point cloud data can also be used for volume calculations and slope area computation, streamlining estimates of required greening materials and preparation of as-built inspection documents.

In recent years, the methods for point cloud scanning themselves have become simpler. For large sites, drone photogrammetry is effective, while handheld laser scanners or LiDAR-equipped smartphones are useful for areas with dense vegetation or partial measurements. In some cases, attaching a high-precision GNSS receiver to a smartphone and walking the slope enabled scanning of a 30 m-class high slope in just a few minutes. Compared to traditional surveying that required expertise, these methods are easier for anyone to handle and allow measurements from safe locations. Introducing point cloud scanning enables comprehensive measurement of the entire slope, reducing “invisible deviations” and improving accuracy in both design and construction while preventing rework.

Visualizing the finished image with AR and speeding up on-site consensus

If the expected finish shown on drawings can be overlaid on the real landscape using AR, anyone can intuitively imagine the final state. Simply holding up a tablet or smartphone can display CG representations of slope protection frames and vegetation placement on the slope, making AR highly effective during meetings with clients and site personnel. It enables immediate sharing of finish images that were difficult to convey with words or 2D drawings, allowing faster agreement on details. Also, visual checks with AR help prevent mistakes. For example, projecting the design model on site allows pre-checks for interference with surrounding structures or whether adequate space is left for people to access. After construction, overlaying the design model on the completed slope lets you visually confirm subtle finish differences that are hard to notice with the naked eye. Using AR in this way reduces rework caused by mismatched expectations and the “it’s not what I imagined” problem after completion.

Effectiveness of smartphone surveying and navigation with high-precision GNSS

High-precision GNSS refers to technologies (such as RTK positioning) that achieve centimeter-level accuracy by applying real-time correction to satellite positioning errors. Recently, this technology has become miniaturized and lower-cost, making it possible to conduct full-fledged surveying by simply attaching an antenna receiver to a smartphone or tablet. Tasks that once required a total station or a skilled surveyor can now be done with a smartphone in hand, recording point coordinates or guiding operators to specified positions, enabling anyone to easily perform surveying and layout marking.

On slope greening sites, this smartphone surveying and navigation delivers significant benefits. For example, when indicating boundary lines of a designated slope area or plant locations, instead of measuring with a tape while referencing paper drawings, workers can simply walk in the direction shown on the smartphone to reach the target point. Visual markers or arrows displayed on the screen indicate “this is the design position” with centimeter-level accuracy, reducing marking errors and cutting work time. Moreover, coordinate data for each measured point are automatically saved and shared to the cloud, allowing the as-built state to be digitized on the spot without worrying about missed measurements or record errors. High-precision GNSS streamlines and reduces the manpower needed for site positioning tasks, shortens the time workers spend in hazardous slope areas, and reduces wait times for surveying—secondary safety benefits that improve overall site safety.

Labor-saving as-built inspections with heatmap comparisons and cloud reports

For slope greening work inspections, it is essential to verify whether the post-construction slope shape matches the design and whether required thickness and gradients are secured. DX tools can dramatically streamline this as-built confirmation. Particularly useful is automatic comparison between design data and as-built point clouds. By overlaying a 3D design model with on-site scanned point clouds, you can generate a heatmap that color-codes the degree of deviation, allowing the overall finish to be assessed at a glance. Areas where the spray thickness is insufficient or where there are protrusions or depressions relative to the design line are visualized in different colors, making it intuitive to judge whether deviations are within allowable ranges. This makes it easier to correct localized defects that were likely to be overlooked, contributing to uniform quality.

Additionally, managing measurement data and inspection results in the cloud simplifies reporting tasks. If as-built tables and cross-sections are automatically generated from point cloud data and stored in the cloud, inspectors can immediately review them from an office PC. There is no need to transfer data via paper records or USB drives, and stakeholders can always access the latest information. Sharing inspection results with the client via the cloud enables immediate pass/fail checks or corrective instructions on the spot, smoothing the handover process. By combining heatmap-based surface comparisons with cloud-based reports, as-built inspection work time and human errors are greatly reduced, improving the overall reliability and speed of inspections.

DX benefits for disaster recovery, steep slopes, and infrastructure maintenance

• Disaster recovery sites: When sudden landslides or slope collapses occur, DX technologies help assess damage and consider recovery methods. Even in hazardous, hard-to-access collapse sites, drone aerial photography and remote point cloud scanning can quickly acquire detailed terrain data. Sharing the situation immediately with relevant agencies via the cloud and projecting post-repair shape images on site with AR to facilitate consensus allows faster development of safe recovery plans than traditional methods. These approaches also help prevent secondary disasters by keeping people away from unstable slopes immediately after an incident.

• Construction on steep slopes: Particularly on very steep slopes, the danger of manual work increases. DX adoption enables surveying and layout marking from safer positions above the slope, or remote construction using robots or automatic spraying devices, enabling labor savings and improved safety. There are reported cases where robot spraying increased construction speed by several times compared to traditional methods, showing that DX can dramatically boost productivity. Real-time measurement data also allow work to proceed while verifying construction accuracy, enabling efficient, high-quality execution even on steep gradients.

• Infrastructure maintenance: For greened slopes along roads or around check dams, DX is also effective for long-term maintenance after completion. Recording and comparing surface changes with 3D scans during periodic inspections makes it possible to quantitatively grasp erosion progression or areas in need of repair. Accumulating point cloud data in the cloud enables trend analysis of deterioration and supports planning repairs with AR on site, realizing more accurate, preventive maintenance than before. Continuously storing digital records shifts maintenance from reactive to preventive, contributing to long-term cost reductions.

Integrated surveying, AR, navigation, and cloud DX with LRTK

Finally, one solution gaining attention for enabling consistent use of these DX technologies is LRTK. LRTK is a system consisting of a small RTK-GNSS receiver that attaches to a smartphone and a dedicated app, enabling point cloud surveying, AR display, coordinate navigation, and cloud integration in a single package. By scanning slopes with a smartphone or tablet camera/LiDAR, you can obtain high-precision 3D point clouds on the spot and upload them to the cloud. The acquired data are automatically analyzed, and tasks such as heatmap comparisons with 3D models and generation of as-built reports can be completed in the cloud. The function to display design coordinates in AR on site allows accurate marking of greening area boundaries and construction positions by viewing the smartphone screen without paper drawings. By digitally linking surveying, construction, inspection, and reporting, LRTK can maximize the effects of on-site DX.

If you aim to improve efficiency and quality in slope greening works, introducing such smart construction systems is one option to consider. Using LRTK lets you easily realize the DX benefits introduced above on a single platform. DX may seem large-scale, but a smartphone-centered system can be introduced even on small sites. Once used on site, you should quickly appreciate its labor-saving and efficiency gains. As labor shortages and work-style reforms are pressing issues, smart construction management incorporating the latest technologies directly enhances on-site productivity and safety. Consider smartphone surveying and AR with LRTK as a trigger to promote DX at your own sites.