Construction site photo records are changing: Streamlining progress management with LRTK-positioned photos

Photographs are indispensable on construction sites for recording work progress and workmanship. Site supervisors and engineers routinely walk the site with a camera in hand, photographing various locations as part of quality control and reporting duties. However, organizing those photos and identifying their locations has required significant effort, and information sharing has remained problematic.

In recent years, the construction industry has been gradually adopting digital technologies to improve efficiency. Initiatives such as the Ministry of Land, Infrastructure, Transport and Tourism’s "i-Construction" promote the introduction of ICT from surveying through construction management, and photo record methods are also poised for major change. In practice, aerial photography with drones and 360-degree cameras have begun to be adopted, but those options can require dedicated equipment and skills. In contrast, LRTK-positioned photos, which can be used conveniently with a smartphone, are attracting attention as a high-precision tool anyone can use. With LRTK (high-precision positioning technology), positioning photos record accurate location information along with each photograph. This dramatically streamlines the previously cumbersome tasks of photo recording and management, greatly improving the accuracy and speed of progress management.

This article reviews the challenges of photo documentation on construction sites and explains in detail what LRTK-positioned photos are, their benefits, and concrete use cases. Let’s look together at how this new form of photo documentation will change on-site progress management.

Table of contents

• The role and challenges of photo documentation on construction sites

• What are positioning photos?

• Benefits LRTK-positioned photos bring to progress management

• Concrete use cases for positioning photos

• Conclusion: The evolution of photo documentation and expectations for LRTK simplified surveying

• FAQ

The role and challenges of photo documentation on construction sites

First, let’s confirm why recording site photos is important. As an objective means of recording construction progress and workmanship, photographs are extremely effective. For example, if you document the construction status at each stage with photos, you can later review the state at that time, and the photos can also be used as presentation material for clients and stakeholders. Because photographs convey the real on-site conditions that are difficult to express with text or drawings alone, they have become indispensable as a reporting and sharing tool.

On the other hand, traditional photo documentation has faced several challenges. Many site personnel feel the heavy burden of the time-consuming task of sorting and categorizing大量の写真 taken on site. Tasks such as organizing folders by date and location or adding captions to each photo can take considerable time every day. In fact, there are cases where manual sorting that used to take two to three hours was shortened to about 30 minutes after introducing digital management. Another common problem is that the exact location of the photographed object can become unknown later. One method is to include the section name or direction on a blackboard or whiteboard in the photo at the time of shooting, but even then people often wonder later, “Where on the site was this photo taken?” Because a single photo lacks spatial information, cross-checking with drawings and locating the photo takes time, and mistakes such as mix-ups or missed records have occurred.

Thus, traditional photo documentation has problems with information organization and location identification, and many photos taken have not been fully utilized. So how can these issues be solved? One answer is the new technology introduced next: “positioning photos.”

What are positioning photos?

“Positioning photos” literally means photos with positioning (location measurement). Specifically, it refers to photo data that combines coordinate information such as the latitude and longitude of the shooting point with the camera’s bearing (direction). Normally, when you take a photo with a smartphone camera, GPS-based location information may be attached to the photo, but that accuracy is typically on the order of several meters to a dozen meters, which is insufficient to indicate precise on-site locations. Directional information is also not included, making it difficult to know “from where and in which direction the photo was taken.”

By contrast, LRTK-positioned photos enable centimeter-level high-precision positioning (cm level accuracy, half-inch accuracy). LRTK is a technology that allows high-precision GPS/GNSS measurement to be performed easily, using a small dedicated device attached to a smartphone. This makes it simple to obtain high-precision position coordinates in real time even on site. When you use the LRTK positioning photo function to take a picture, the photo file records the precise coordinates (the positioning point) at that moment, and the device’s electronic compass and gyroscope also save the shooting direction as data. For example, information such as “photographed from the southwest of Building 〇〇 toward the northeast” or “at a height of ○ m above ground” can be included, enabling viewers to grasp the space including areas not visible in the image.

In other words, positioning photos are a new recording method that integrates photos and positioning data. This integrates what used to be handled separately—the “image information” and the “location information”—so the photo itself becomes a valuable dataset that carries on-site spatial information. In the next section, we will look at the specific benefits this positioning photo brings to on-site progress management.

Benefits LRTK-positioned photos bring to progress management

Introducing LRTK-positioned photos improves progress management on construction sites in various ways. Here are the main benefits.

• Streamlined photo organization: Because location tags are attached to photos at the time of shooting, the effort required to sort photos later is greatly reduced. Photos can be automatically organized and searched based on shooting date and location information, allowing you to identify “which photo is from which location” at a glance. This eliminates the manual folder-sorting work and reduces the burden on site staff and overtime.

• Accurate progress assessment: With centimeter-level position information (cm level accuracy, half-inch accuracy), you can accurately identify the construction location each photo shows. Small positional differences are backed by data, enabling more accurate evaluation of progress. For example, even in rebar photos of foundation work, you can determine “which column and which part” from the location data, making it easy to compare before-and-after states of the same spot later.

• Reproducibility of shooting points: Using the coordinate data from positioning photos, it is easy to retake photos from the same point and angle as past photos. LRTK systems have functions that can navigate you to past shooting points, facilitating fixed-point observations to record chronological changes. This allows precise time-series comparisons and identification of changes in workmanship, and helps prevent missing records or photography mistakes.

• Faster information sharing: Positioning photos taken on site can be synced to the cloud and shared immediately. Photos taken on site can be uploaded to the cloud on the spot, enabling office staff and remote stakeholders to view them in real time. Because photos include accurate location information, recipients can pinpoint the location on a map without verbal explanations like “a photo near 〇〇.” This makes it possible to communicate quickly while sharing the same information with supervisors or clients who are not on site.

• Enhanced integration with drawings and models: The precise coordinates of each photo make it easy to link photos to electronic maps, CAD drawings, or BIM models. For example, you can plot photo locations on a map in the cloud or embed photos in the corresponding spots of a 3D model—this kind of data linkage becomes possible. Integrating on-site photo information with design drawings or geographic information systems (GIS) enables more intuitive and complete progress tracking.

• Simplified reporting and inspections: Creating photo ledgers and final inspection documents is also streamlined. Because positioning photos include highly reliable location and time data, you no longer need to write long explanatory text when inserting photos into reports. Photos that clearly show “when, where, and what was photographed” can be used directly as evidence, making it easier to prepare persuasive documents for regulatory submissions or internal reports quickly. At project completion, having photos and positioning data for all construction locations prevents last-minute scrambling to collect records before inspections.

As shown, LRTK-positioned photos offer many advantages that simultaneously improve the quality and efficiency of progress management. Not only do they make daily on-site record tasks smarter, but they also provide consistent benefits for subsequent verification work, communication, and the quality of final deliverables.

Concrete use cases for positioning photos

Now let’s look at how positioning photos can actually be used on site in concrete scenarios.

• Fixed-point progress recording: Decide shooting points at key locations and periodically take positioning photos from the same points. If you pre-register fixed points such as the four corners of a building or representative points on each floor, LRTK can navigate you to those locations so you can always record photos with the same angle and distance. Accumulating photos with the same composition weekly or monthly allows you to accurately compare the erection of steel frames or the progress of interior work over time, greatly contributing to visualizing progress. Moreover, fixed-point observation enables objective assessment of construction progress, helping to detect delays or workmanship issues early and take prompt corrective actions.

• Reliable evidence of construction content: For works that will later become hidden, such as buried piping or rebar installation, recording them with positioning photos ensures peace of mind. For example, if you capture the location and depth of piping before burying it, you can later verify with drawings that the installation was made in the correct position. If questions arise later such as “Is the piping located differently from the drawings?”, having positioning photos as irrefutable evidence allows rapid confirmation of facts. Accurately recording hidden processes helps precisely locate items for future excavation or repairs, which supports efficient work planning.

• Rapid sharing when trouble occurs: When unexpected problems occur on site (e.g., discovery of underground obstructions or detection of construction errors), positioning photos are powerful. By photographing the situation on the spot and immediately sharing the photo with accurate location data, remote project stakeholders can quickly align their situational awareness. This eliminates the need to explain which spot on the drawings the issue occurs, facilitating timely decision-making and emergency responses. As a result, time loss from problem detection to countermeasure planning is minimized.

• Handover for post-completion maintenance: After project completion, positioning photo data remains useful for the maintenance phase. If completion documents include photos with location information, inspections years later can accurately determine “what was here originally” and “what condition it was in.” Management of crack repair histories and buried object locations can be centralized, drastically reducing the effort to retrieve past records during future renovation or inspection tasks. Such retained photo records can inform future construction plans, additional works, or inspections, contributing to long-term maintenance efficiency. Thus, the usefulness of positioning photos extends beyond construction to post-completion asset management.

As the above demonstrates, LRTK-positioned photos support site management in many scenarios. From fixed-point progress monitoring to reliable documentation of workmanship, rapid trouble response, and future data reuse, they are a tool that enhances the value of photo documentation across a wide range of situations.

Conclusion: The evolution of photo documentation and expectations for LRTK simplified surveying

Positioning photos—digitalized and high-precision photo documentation—are a technology that can significantly advance progress management on construction sites. Tasks that previously relied on manual labor, such as photo organization and location confirmation, can be automated, and record accuracy dramatically improves, raising the efficiency and reliability of site management. In addition, clear records with location information increase project transparency and help build trust with clients and regulatory authorities. Beyond saving small daily tasks, the accumulation of “reliable data to rely on when needed” positions this technology as an important pillar of on-site DX (digital transformation).

Moreover, LRTK’s potential is not limited to photo documentation. Leveraging LRTK’s high-precision positioning, it can also be used as a simplified surveying tool. For example, applying the same mechanism as positioning photos makes it possible to measure coordinates of objects captured in photos or acquire point cloud data of the site in a short time—simplified surveying becomes accessible to anyone. Without specialized surveying equipment or highly experienced technicians, a smartphone with LRTK enables quick collection of necessary surveying data, letting teams measure current conditions or check as-built states during construction. Advancing from photo documentation to streamlining surveying work itself is a unique strength of LRTK.

The evolution of photo documentation is sure to change site workflows. If your site is struggling with photo management, consider adopting this new method using LRTK-positioned photos. You can expect not only more efficient progress management but also future reductions in surveying labor and other benefits. Embrace cutting-edge technology to improve productivity and working styles on construction sites.

FAQ

Q: What are positioning photos? A: Positioning photos combine photos with precise position coordinates and direction data recorded at the time of shooting. Using high-precision positioning technologies such as LRTK, centimeter-level position information (cm level accuracy, half-inch accuracy) can be attached to each photo, making it a new recording method that clarifies “when, where, and what was photographed.”

Q: Are special devices or knowledge required? A: Little specialized knowledge is required to use positioning photos. In the case of LRTK, you attach a small dedicated positioning device to a commercially available smartphone and use a dedicated app, allowing anyone to handle it easily. Complex settings are unnecessary, and it is designed so that site personnel can use it naturally in their daily work.

Q: How is this different from photos with a smartphone GPS function? A: Standard smartphone GPS photos have accuracy on the order of several meters, which is insufficient for precise on-site location records. They also do not include bearing (the direction the photo was taken). LRTK-positioned photos correct satellite positioning errors to achieve dramatically higher accuracy (centimeter-level) and also obtain data such as shooting direction and altitude. Therefore, both in terms of recording accuracy and information content, they are a step above conventional GPS-tagged photos.

Q: Can it be used at sites without internet coverage? A: Yes. LRTK supports Japan’s quasi-zenith satellite system (Michibiki) centimeter-class augmentation service (CLAS), enabling high-precision positioning even in areas with no mobile signal, such as mountainous regions or near tunnel openings. Because it can position without relying on real-time communications, it is effective for construction records in areas with limited infrastructure and for documenting disaster sites immediately after an event.

Q: How can positioning photo data be shared and utilized? A: Captured positioning photo data can be uploaded to the cloud with one click and shared instantly with office PCs or other team members. By issuing a sharing link, clients and contractors without dedicated software can also view the photos. In the cloud, photos can be mapped on a map or displayed in chronological order, enabling utilization beyond a simple photo album as living project data for internal and external use.

Q: Will adding high-precision location data to photos affect file size or communication? A: The additional data such as coordinates are very small, so photo file sizes do not increase significantly. For example, only a few kilobytes of information are added to a photo of several megabytes, so the impact on storage and transmission time is minimal. Cloud synchronization is also optimized to work reliably over mobile networks.