Towards Eliminating Near-Miss Incidents: Improving Surveying Safety with AR Heat Maps

Contents

• What is a near-miss?

• Safety challenges at surveying sites

• What is an AR heat map?

• Why AR heat maps improve safety

• Concrete use cases of AR heat maps

• Recommendation: simple surveying with LRTK

• FAQ

What is a near-miss?

Workplace accidents in the construction industry remain frequent, and preventing serious accidents requires identifying and addressing hazards at the near-miss stage. A near-miss refers to an experience that did not result in an accident but gave a fright or a sudden shock—for example, almost slipping while surveying or nearly coming into contact with heavy machinery. Although these events may seem like “nothing happened,” they provide important information from which safety lessons can be learned. In safety management, it is often cited by Heinrich’s Law that “behind one major accident there are 29 minor accidents and 300 near-misses.” By not leaving near-misses unaddressed and by sharing and countering them, future major accidents can be prevented. For that reason, many sites report near-miss cases and create near-miss maps, promoting safety education through the visualization of hazardous locations.

That said, relying solely on paper maps or verbal notices has limits for making hazard information immediately usable on site, and there are situations where alerts cannot be fully enforced. Enter the latest technology called the AR heat map. By leveraging AR (augmented reality), it becomes possible to visualize hidden hazards and work areas on site and intuitively alert workers. This article explains in detail how AR heat maps can enhance the safety of surveying work and how they work and can be applied to eliminate near-misses.

Safety challenges at surveying sites

Surveyors enter virtually every part of a site, so they constantly face safety risks. For example, surveying near operating construction machinery might result in almost contacting equipment; during road surveys a vehicle might pass very close by; or trying to measure a slope might lead to an almost slip—such near-miss situations can occur. Surveying work often demands concentration on instruments and measurement points, which can lead to reduced attention to surroundings and difficulty noticing hazards coming from blind spots. Furthermore, surveying is often performed by one person or a small team, making it hard to assign a dedicated watcher for hazards. Site layouts and hazardous areas change daily, so merely marking areas with barrier tape or cones can be insufficient. In busy sites, even if someone verbally warns “don’t go there, it’s dangerous,” new entrants or workers from different teams may not get the message, and surveyors could unintentionally enter hazardous zones. Thus, at surveying sites, insufficient transmission and display of hazard information contribute to near-misses, and new measures are required to ensure safety.

What is an AR heat map?

AR (augmented reality) is a technology that overlays computer graphics or textual information onto camera views from smartphones, tablets, or smart glasses. You may have seen it in games or tourist guides. In the construction industry, AR is already being used to project completed models on site or to display underground piping routes in a see-through view. Recently, by combining RTK-GNSS for centimeter-level positioning accuracy (half-inch accuracy), AR displays can be aligned with minimal positional offset so they match actual coordinates precisely.

A heat map is a chart that expresses the magnitude or frequency of data using color gradients. By showing high-risk areas in red and low-risk areas in blue, for example, one can instantly identify “hot spots” requiring attention. An AR heat map brings this heat-map visualization into AR. Specifically, it displays colored distributions and frequencies of hazards overlaid on the real site view. For example, areas with many past near-misses appear bright red, while locations with few incidents show blue or green. Workers can simply point their phones around and intuitively grasp where risks are lurking. Traditionally, workers had to consult danger maps on drawings or read lists to know where to be careful, but AR heat maps make information appear as if it is part of the site, making it easier to understand and helping prevent oversights in safety checks.

Why AR heat maps improve safety

• Intuitive identification of hazards: AR heat maps let users instantly see dangerous spots. Viewing a red-highlighted area through a phone screen immediately signals it as a place to be cautious. This is faster and easier to understand than reading text, making it effective at preventing missed safety checks.

• Prevents gaps in hazard information sharing: AR heat maps enable all workers to visually share the same information. Even those who missed the morning briefing or are unfamiliar with the site can learn hazard locations on-site through an app. Digital tools distribute safety knowledge to everyone without relying solely on veteran experience.

• Real-time risk visualization: If site conditions change and new hazards arise, updating the data immediately reflects those changes in AR. This real-time capability addresses what posted notices or signs cannot, allowing up-to-date alerts even on rapidly changing construction sites.

• Prevents accidental entry into hazardous areas: AR can display virtual exclusion lines or warning signs to prevent workers from inadvertently stepping into danger zones. Even where boundaries are hard to discern with the naked eye, AR makes it clear “danger beyond this point,” helping maintain safe distances.

• Raises safety awareness: Visual feedback heightens workers’ safety awareness. Showing risks around them in color makes workers more conscious of why a place is dangerous and leads them to act more carefully. As a result, the occurrence of near-misses themselves is expected to decline.

Concrete use cases of AR heat maps

• Visualizing heavy equipment operating areas: AR can display alert zones around operating machinery and vehicles. For example, showing a crane’s swing radius or an excavator’s working radius in red, and issuing warnings if people enter that area, can reduce the risk of contact accidents. This reassures both equipment operators and nearby workers.

• Indicating work areas and exclusion zones: Safe entry areas and restricted dangerous zones can be color-coded or separated by virtual fences in AR. Surveyors can compare their current position through AR with permitted work areas, preventing accidental entry into hazardous zones. It can also be used to show pop-up warnings if unauthorized personnel approach a work area.

• Pre-display of buried utilities and obstacles: AR can visualize the locations of underground pipes, cables, and obstacles that are not within direct sight. Before excavation, pointing a smartphone to view underground utility routes in a see-through AR display can prevent near-misses like almost damaging a water pipe with a shovel. Similarly, AR can emphasize hazards that are hard to see at night or in bad weather, aiding safety checks.

• Contactless inspection of hazardous locations: For steep slopes or areas at risk of collapse, it is important to assess conditions without entering them. Using a smartphone camera or LiDAR to scan terrain from a distance and displaying the collected data as an AR heat map on the spot allows evaluation of surface elevation differences or deformations without stepping onto unsafe ground. This enables non-contact inspections even in places humans cannot approach, helping prevent secondary disasters.

• AR sharing of near-miss history: By database-izing past near-miss cases and reflecting them on an AR map, “near-miss visualization patrols” become possible. For example, placing a warning icon in AR at the location of a near-miss that occurred yesterday lets workers check it on-site the next day. Tapping a pin can display details and countermeasures, making it an effective on-site safety education tool. AR shares lessons that paper noticeboards or morning meetings cannot fully convey as live on-site information. Initiatives are also underway to reflect proximity alarm position data from sensors mounted on heavy equipment and danger-detection data from AI analysis of surveillance camera footage in heat maps. Combining IoT, AI, and AR will enable safety management based on more objective data.

In these ways, AR heat maps can be applied in many situations and are expected to become a new trump card for safety measures. Trials have already begun at some sites, and feedback like “hazardous spots are visible at a glance” and “even inexperienced workers can work safely” has been reported. There are also reports of reductions in near-miss incidents, suggesting the technology has the potential to change site safety culture. More sites are moving from demonstration phases to full implementation, and the day when AR heat maps become a standard tool for safety management may not be far off.

Recommendation: simple surveying with LRTK

As a solution to easily realize AR heat maps on site and improve safety, there is LRTK. LRTK is a next-generation surveying system composed of an ultra-compact RTK-GNSS receiver that can be attached to a smartphone and a dedicated app. By attaching the pocket-sized device to a phone and launching the app, anyone can immediately begin centimeter-level positioning (half-inch accuracy) and AR displays. The accuracy rivals that of conventional expensive surveying instruments, and experiments comparing measurements with national reference GNSS points have shown errors on the order of a few millimeters.

With LRTK, tasks that used to require skilled surveyors and bulky equipment can be completed with just one smartphone. For example, even without setting reference points, one can instantly obtain high-precision positioning by using Japan’s Quasi-Zenith Satellite System (Michibiki) centimeter-level augmentation service (CLAS) or VRS reference station data over the network. Acquired data is automatically synchronized to the cloud, allowing progress to be shared with office colleagues while on site. Advanced functions such as scanning the surroundings with the phone’s built-in LiDAR scanner and immediately displaying differences between as-built and design as an AR heat map on site can be achieved safely by a single worker. As a result, it can reduce personnel and shorten working time, thereby reducing the time people spend in hazardous zones.

The LRTK series is designed for use in construction and civil engineering sites, offering stable positioning performance and durability even in bad weather and harsh environments. It supports iOS devices such as iPhone and iPad and is noted as a solution compatible with the Ministry of Land, Infrastructure, Transport and Tourism’s i-Construction requirements. It is already being introduced at construction sites across the country, dramatically shortening surveying and as-built confirmation times and being praised for its ease of use by non-specialist site staff.

If you want to try simple surveying using state-of-the-art RTK AR technology, please consider utilizing LRTK. Product information and case studies are available on the [LRTK official site](https://www.lrtk.lefixea.com). You are welcome to contact them with questions or for demo inquiries. Implement LRTK to realize smart surveying that balances safety and productivity.

FAQ

Q: What do I need to use an AR heat map? A: Basically, you need a smartphone or tablet capable of AR display, a GNSS receiver to obtain positioning information, and an application to display hazard data. Recent smartphones come with built-in AR features, and for more precise alignment it is ideal to combine an RTK-GNSS unit (such as a device like LRTK). If you import pre-created near-miss map data or design drawings into the app, you can overlay them on-site as AR heat maps.

Q: Do I need specialized knowledge to introduce or operate it? A: No, systems are designed to be usable without special expertise. Dedicated apps have intuitive interfaces, and information appears just by pointing a phone camera. Some initial practice is needed, but even those without surveyor qualifications should be able to learn the basic operation in a short time. Experienced veterans, who can intuitively identify hazards, will likely find it especially effective.

Q: Will AR heat maps really reduce accidents? A: AR heat maps are a tool to support hazard alerts, but if used appropriately they are expected to contribute to reductions in near-misses and accidents. Being able to visually see hazard locations increases each worker’s awareness and is expected to reduce small mistakes. However, do not rely solely on AR and neglect other safety measures. AR heat maps should complement and strengthen conventional safety management (such as KY activities and wearing protective equipment).

Q: How accurate is the displayed position? A: It depends on the equipment used, but combining high-precision GNSS can provide accuracy within a few centimeters (within a few inches). For example, using an RTK-capable system like LRTK allows virtual warning displays to overlap almost exactly with the intended positions on the ground. Conversely, smartphone-only GPS can have errors of several meters (several ft), making it unsuitable for precise alignment. To accurately indicate hazards, efforts to improve precision such as using RTK or calibrating with known points are recommended where possible.

Q: Can it be used indoors or in tunnels where GNSS is not available? A: In locations where satellite signals cannot reach, RTK-GNSS-based AR displays are unfortunately difficult. In such cases, marker-based AR or a combination with conventional surveying methods (total station, etc.) is necessary. However, recent technological advances have introduced indoor positioning using UWB or Bluetooth and self-positioning using pre-acquired point cloud data, enabling AR displays without GNSS. Indoor and underground AR use is expected to expand gradually.

Q: What kinds of sites and applications can it be used for? A: It can be applied to all kinds of civil engineering and construction sites. It is suitable for roadworks and land development, from large-scale sites like bridges and tunnels to small-scale repair works and surveying—wherever hazardous working conditions exist, AR heat map visualization can aid safety measures. It is also being applied beyond construction, such as factory equipment inspection and infrastructure inspection, and use cases are expected to expand.

Q: Is the cost worth the benefit? A: While safety is priceless, the benefits of introducing AR heat maps are significant. Reducing near-misses leads to fewer work stoppages and rework for countermeasures, improving productivity. Preventing accidents avoids not only human harm but also subsequent construction delays and material loss costs. Recent smartphone-based solutions have reduced initial investment compared to conventional specialized equipment. Depending on site scale, the cost-effectiveness is generally high when considering safety improvements and efficiency gains. Additionally, AR heat maps contribute to quality control and work efficiency, offering comprehensive benefits.

Q: How will AR heat map technology develop in the future? A: AR heat map technology is expected to advance further. On the hardware side, the spread of smart glasses will bring an era where AR information can be checked continuously hands-free. On the software side, integration with hazard-prediction AI and real-time information sharing in the cloud will strengthen mechanisms for sharing safety information across entire sites. In the future, AR heat maps are expected to become a commonplace safety management tool, contributing to workplaces with zero near-misses. For example, a future where all workers wear smart glasses that automatically highlight hazards in their field of view could make the elimination of workplace accidents a realistic goal. Expectations for digital technologies are also rising among government agencies and corporate safety officers, and it is hoped that site DX and the cultivation of safety culture will progress together.