Innovating On-site Response with LRTK-capable Smartphone Surveying! A Guide to Simplified Plan Drawing Creation

Plan views (planar drawings of the site) are indispensable for construction planning and reporting. However, actual plan drawing creation has become a major burden on-site. Traditionally, surveying specialists used large-scale equipment to measure and then drafted drawings in the office, which required significant time and effort.

In recent years, the construction industry has been pushed by DX (digital transformation) to respond more quickly on-site. For example, there are increasing cases of checking for discrepancies with design drawings during construction or quickly creating plan views of damage after disasters. The traditional approach often could not keep up with these needs. One promising solution is a new surveying method that utilizes smartphones. This article explains the advantages and practical procedures for creating plan views using LRTK-capable smartphone surveying, taking into account the challenges of conventional methods. Let’s look at how on-site responses can be innovated.

Conventional plan drawing methods and their limitations

First, let’s summarize the methods that have commonly been used to create plan drawings and their limitations. Traditionally, surveyors performed field surveys with specialized equipment such as transits and total stations, and drawings were produced based on that data. On small sites, manual measurements using tape measures and spirit levels were sometimes relied upon. In any case, dimensions were measured on-site, notes were taken, and drawings were produced after returning to the office, requiring a great deal of time and effort.

Conventional methods have the following issues:

• Specialization and manpower: High-precision surveying requires survey technicians with specialized knowledge, and it is often difficult for one person to handle, making multi-person work necessary.

• Bulky equipment: Transporting and setting up tripods and large surveying equipment is laborious, making them unsuitable for cramped sites or urgent measurements.

• Time and cost: From planning the survey to execution and drawing creation takes time, and work may be halted during this period. Outsourcing to surveying companies can also be costly.

• Errors and omissions: Handwritten notes and later office drafting can lead to human errors, resulting in missing measurements or record mistakes that cause inaccuracies in drawings.

• Difficulty of frequent updates: Even when construction changes or additional surveys are required, it is difficult to immediately re-survey and update drawings each time, so the latest site conditions are not easily reflected.

Due to these constraints, plan drawing creation has been regarded as “inevitably time-consuming” and “something that must be left to specialists.” However, technological advances are overturning these assumptions.

Changes brought by LRTK-capable smartphone surveying

Enter a new surveying method using smartphones. In particular, LRTK-capable smartphone surveying has the potential to solve conventional issues at once. LRTK enables high-accuracy positioning technology (RTK: Real Time Kinematic) on smartphones: a compact dedicated receiver is attached to the smartphone, and satellite positioning errors are corrected in real time, allowing a smartphone alone to achieve accuracy comparable to traditional surveying equipment.

LRTK smartphone surveying brings the following changes to on-site plan drawing creation:

• Ease of use for anyone: With a simple setup of a smartphone and a compact device, construction managers and workers without specialized surveying skills can operate it. The pocket-sized equipment allows measurements to be started immediately when needed, enabling surveying during breaks in work.

• Real-time high accuracy: The typical smartphone GPS error of about 5-10 m (16.4-32.8 ft) can be reduced by LRTK to about 1-2 cm (0.4-0.8 in) horizontally and within about 3 cm (1.2 in) vertically, achieving centimeter-level accuracy. High-precision position information can be obtained on-site, allowing immediate verification and decision-making.

• Labor reduction and speed-up: One person can conduct surveys simply by carrying a smartphone, eliminating the need to set up heavy tripods or use surveying assistants. The time from measurement to drawing is drastically reduced; plan drawings that used to take several days can be completed on the same day, and in some cases while working on-site.

• Digital data integration: Measurement data are automatically recorded in smartphone apps and can be shared via the cloud. Coordinates and tracks obtained on-site become electronic data, eliminating the need for office data entry and enabling immediate import into CAD or integration with other systems.

• Multifunctional use: Because smartphones can be combined with cameras and AR (augmented reality), use cases extend beyond simple coordinate measurement to include geotagged photos, on-site projection of design drawings via AR, and 3D modeling through point-cloud scanning. This potential allows efficiencies across on-site tasks beyond just plan drawing creation.

Concrete steps to create plan drawings using smartphone surveying

Now let’s look at the process for actually creating a plan drawing with smartphone surveying. Unlike manual drafting or creating drawings from scratch in CAD, surveying and drafting can be performed as a continuous workflow. Below are the general steps.

• Preparation: Attach an LRTK-capable compact receiver to the smartphone and launch the dedicated app. Ensure the device is receiving satellite signals for positioning and able to obtain correction information (via the Internet or compatible satellite signals). Before surveying, verify the reference coordinate system (e.g., plane rectangular coordinate system) settings and prepare to start measurements.

• Selecting measurement points: Decide the area and points to be reflected in the plan drawing. For example, for land boundaries, identify the positions of boundary markers and vertex points; for structure layout, the corners of buildings or planned installation locations; for disaster sites, the outer perimeter of damaged areas. Plan the survey to ensure no measurement omissions.

• Executing positioning: Move to the target position with the smartphone and tap the positioning button in the app to record coordinates. Latitude, longitude, and elevation for each point are automatically obtained, and names or notes can be added and saved as needed. For linear data like site perimeters, use continuous positioning mode to record tracks while moving, efficiently capturing the data. During surveying, the current position and acquired points are displayed on the screen, allowing you to check the map and avoid missing measurements.

• On-site verification: After measuring, display the recorded points and lines on the app’s map screen to confirm a draft of the plan drawing. Coordinates are plotted on the map, so you can immediately grasp shapes and positional relationships. If any points are missing or require correction, perform additional measurements to supplement the data. Switching the smartphone view to a profile (vertical) view allows checking elevation differences, enabling three-dimensional checks when necessary.

• Data synchronization and sharing: Measurement data can be uploaded to the cloud with one tap and instantly shared with the office PC or stakeholders via the Internet. While on-site, you can have colleagues in the office view the latest survey results and request instructions. On the cloud, acquired point clouds and coordinate data can be displayed in 2D or 3D, allowing remote stakeholders to understand on-site conditions.

• Output as drawings: Collected coordinate information can be exported in common formats such as CSV or DXF. For example, trajectory data can be imported directly into CAD software and used as the boundary lines of a site plan. The app can also generate simple PDF drawings for printing, and it is easy to overlay and compare with existing drawings (CAD data). The ability to rapidly complete final plan drawings based on data acquired on-site is a major advantage.

Use cases: boundary checks, structure layout, disaster sites, etc.

LRTK-capable smartphone surveying can be applied to plan drawing and surveying tasks in various scenarios. Here are representative examples.

• Boundary checks: Smartphone surveying is useful for confirming the positions of boundary markers and partition lines. Boundary point coordinate checks that used to require a surveyor can now be performed in-house with a smartphone in a short time. By comparing obtained boundary coordinates with existing land survey data, discrepancies can be quickly identified. For new partitioning, you can measure points on-site and set temporary markers easily.

• Structure layout: Smartphone surveying is also effective for layout tasks to place buildings and structures accurately. Based on coordinates specified in design drawings, on-site markers can be set using smartphone navigation or AR displays, reducing the effort previously needed for batter boards and staking. For example, positions for lighting poles or signposts can be calculated from survey data and guided by the smartphone to prevent placement errors and efficiently install them. For as-built inspections, measuring finished positions on the spot and comparing them to drawings facilitates smooth quality checks.

• Disaster sites: Creating plan views of conditions after earthquakes or landslides is also effective with smartphone surveying. The extent of hazardous areas and the positions of damaged structures can be quickly measured on-site and plotted on digital maps. Initial response that used to wait for specialized teams can now be performed by municipal staff or on-site personnel using a single smartphone to create a rough current-condition map, aiding rapid planning of emergency measures. Furthermore, because surveying can be done with light equipment even amid post-disaster chaos, you can quickly collect necessary information with high mobility.

Simplification of data management and drawing output

As smartphone surveying becomes widespread, organizing survey data and reflecting it in drawings will be greatly simplified. Measurement point data that used to be managed in field notebooks or Excel can be centrally managed in digital form.

Specifically, coordinate values and photo data acquired on-site are all stored in the cloud, allowing drafters to use the data directly. There is no need to re-enter notes into CAD while referring to paper field books, eliminating transcription errors. Also, because an automatically drawn base map generated from coordinates can be refined for details, even those without specialized drawing skills can produce high-accuracy plan drawings.

Moreover, once survey data is stored in the cloud, integrating later additional survey data is easy. For example, as construction progresses and new structures are measured, those coordinates can be overlaid on existing data to update drawings. Historical data is retained, allowing traceability of “when, where, and who” measured each point, and functioning as a ledger for maintenance management. By making data management and drawing output seamless, information sharing between field and design/management departments accelerates, improving overall operational efficiency.

Benefits for small and medium contractors and municipalities

The advantages of LRTK-capable smartphone surveying extend beyond large companies to small and medium-sized contractors and municipalities. Let’s see the benefits for each.

• For small and medium contractors: Smaller businesses that cannot afford expensive surveying equipment or outsourcing can adopt smartphone surveying with a reasonable investment. Completing surveys in-house reduces outsourcing costs and enables nimble responses even with a small workforce. Even without experienced surveyors, site supervisors and workers can measure and create drawings themselves, helping to alleviate labor shortages. The ability to rapidly create as-built drawings for each contract and include them in proposals is also a strength for agile business development.

• For municipalities: Local governments frequently need surveying for infrastructure inspections and disaster response but often face limited specialized staff and budgets. If municipal staff can operate smartphone surveying, they can perform simple surveys for road and park maintenance as needed and update ledgers and drawings in a timely manner. Creating damage maps quickly during disasters speeds up information provision to residents and planning of recovery measures. Affordable, portable smartphone surveying equipment is also useful as municipal disaster prevention equipment and can contribute to improved regional disaster resilience.

Future outlook and integration with BIM/CIM and maintenance management

Plan drawing creation using smartphone surveying is expected not only to change on-site work styles but also to play an important role in future data integration with BIM/CIM and maintenance management.

Initiatives such as i-Construction and BIM/CIM promoted by the Ministry of Land, Infrastructure, Transport and Tourism advocate consistent digital data utilization from construction through maintenance. High-precision coordinate data and point clouds acquired by LRTK-capable smartphone surveying can be directly incorporated into 3D models and GIS. For example, as-built data surveyed by smartphone during construction can be reflected in BIM models to examine discrepancies with design in near real time. Using AR, it is also easy to project BIM/CIM model layouts onto the site and share the envisioned completion among stakeholders from the planning stage.

After handover, smartphone surveying devices are also useful for maintenance. Geotagged photos taken during inspections are effective for recording asset conditions over time and creating a database. Since photos can be stored with coordinates and orientation, the same location can be accurately re-surveyed years later to objectively compare deterioration. In the future, such field-collected data will be used to update digital twins (virtual infrastructure management models), and smartphone surveying may become part of the infrastructure maintenance platform.

As smartphone technologies improve (standard inclusion of high-precision GNSS and better sensors) and communication environments advance, LRTK surveying is likely to become a common tool on more sites. If that happens, not only plan drawing creation but also 3D measurements, as-built management, and inspection/maintenance records may all be handled by a single smartphone per person. LRTK-capable smartphone surveying will increasingly gain prominence in promoting on-site DX.

Conclusion and a natural path to LRTK surveying

This article started from on-site challenges in creating plan drawings and introduced the solutions and outlook provided by LRTK-capable smartphone surveying. Surveying and drawing creation that were once left to specialists are becoming tasks anyone can perform quickly and accurately with just a smartphone. Smartphone surveying capable of centimeter-level positioning is a powerful ally that can innovate on-site responses while achieving both efficiency and quality.

Once you start using it, its ease and speed often lead to comments like “we can’t go back to the old way.” Simplifying plan drawing creation not only shortens drawing tasks but also accelerates on-site decision-making and contributes to workstyle reform. If your site spends significant time or cost on plan drawing creation, consider LRTK-capable smartphone surveying as an option. Adopting the latest technology can bring big benefits even to small sites and lay the groundwork for future BIM/CIM and maintenance management.

LRTK smartphone surveying is becoming the new standard for plan drawing creation. Experience this innovative tool that can dramatically boost on-site productivity and responsiveness.