Seven Steps to Successfully Carry Out 3D Surveying of Buried Cultural Heritage

3D surveying of buried cultural heritage can enhance record preservation and visualize investigative results, but if handled incorrectly it is a field prone to insufficient data collection on site, deliverables that are difficult to use downstream, and the need for re-surveying. For practitioners, in particular, it is necessary to proceed while simultaneously considering excavation progress, coordination with stakeholders, recording accuracy, and where deliverables will be used; it is not sufficient to simply bring in equipment and measure.

Moreover, buried cultural heritage often includes subjects that cannot be returned to their original state once excavated. Therefore, 3D surveying requires greater reproducibility of records, accuracy of positional relationships, and stability of work procedures than general surveying or photography. Changes in soil layers, overlapping features, artifact recovery conditions, narrow investigation areas, sunlight conditions, and constraints on workspace—all site-specific conditions—greatly affect results. To prevent failures, it is important to design the entire workflow from pre-introduction preparation through on-site measurement, data organization, and deliverable verification.

This article explains seven steps for practitioners who are about to undertake 3D surveying of buried cultural heritage, organized to make on-site failures less likely. It lays out what should be decided at each stage, what to watch for, and how to ensure deliverable quality following the flow of practical work. It is useful not only for those handling 3D surveying for the first time but also for organizations that have relied mainly on outsourcing and are considering in-house execution or operational improvement.

Table of Contents

• Why failures are likely in 3D surveying of buried cultural heritage

• Step 1 Define the purpose of the survey and the deliverables first

• Step 2 Organize the subjects and site conditions in advance

• Step 3 Decide accuracy standards and how to handle coordinates

• Step 4 Design measurement methods and a photography plan suited to the site

• Step 5 Enforce recording rules on the day of measurement

• Step 6 Perform data processing and quality checks in stages

• Step 7 Organize with an eye toward post-delivery use

• Summary

Why failures are likely in 3D surveying of buried cultural heritage

The main reason failures are likely in 3D surveying of buried cultural heritage is that many necessary judgments must be made on site and those judgments are difficult to undo. Unlike construction sites or general facility surveys, archaeological investigations change day by day. Features that were not visible yesterday may appear, excavation may change the ground surface, and shooting conditions can vary greatly due to rain or sunlight. Amid such changes, you must make appropriate on-the-spot decisions about what to record, to what accuracy, at what timing, and in what format.

Furthermore, failures in 3D surveying are often hard to notice on site and tend to be discovered during post-processing. Even if things look adequately captured in the field, insufficient image overlap, remaining blind spots, or inconsistent handling of control points can lead to holes in models or dimensional mismatches during modeling. If problems are noticed after the site work is finished, reproducing the same conditions is often impossible. Especially when recording temporary states such as soil section faces or artifact recovery conditions, re-surveying may be practically impossible.

In addition, 3D surveying of buried cultural heritage is not just about preserving shape. Deliverables must withstand multiple uses: positional relationships among features, artifact correspondence, consistency with plan drawings, report preparation, research use, preservation records, and public outreach. If the purpose is ambiguous, you may end up with outputs that are highly accurate but hard to use, or visually appealing but insufficient as records. That is why it is important to carefully design procedures before selecting equipment.

Step 1 Define the purpose of the survey and the deliverables first

The first step is to clarify why the 3D survey is being conducted. If this is left vague, you may spend unnecessary effort or, conversely, lack required information. 3D surveying of buried cultural heritage may have preservation recording as the main purpose, or it may be intended primarily to assist in drafting, quantity estimation, cross-section verification, explanatory materials for investigative results, public outreach to residents, educational use, or future comparative verification. Required accuracy, representation methods, deliverable formats, and work time vary greatly depending on the purpose.

For example, if the main purpose is to grasp the overall planar layout of features or to document site progress, overall shape readability and work efficiency are prioritized. Conversely, if you need to confirm fine excavation shapes of a feature, tool marks on stones, or subtle elevation differences, a denser and more stable acquisition method is required. The data structure needed also differs depending on whether the data will be used for figures in an investigation report or intended for future reuse as a 3D model. If you aim for an all-purpose dataset without clarifying purpose, only the on-site and processing burdens will increase.

Along with the purpose, decide the final deliverables at the start. Clarify whether point clouds, 3D meshes, orthophotos, the ability to convert to plans and sections, or lightweight, easy-to-view data are required. If on-site staff, report authors, preservation managers, clients, and supervisors are separate, share who will use what from the outset. If the image of the deliverable is vague, post-processing may result in mismatches like “this isn’t what we wanted.”

At this stage, the important thing is not to be overly ambitious. Due to constraints in the investigative process, it is unrealistic to capture everything perfectly in one pass. By dividing tasks—days prioritizing overall site recording, areas prioritizing detailed recording, and targets considered for public-facing aesthetics—work becomes more stable. If you define purpose and deliverables first, subsequent accuracy settings and selection of measurement methods will remain consistent. The first step to preventing failure is to verbalize what constitutes success before entering the site.

Step 2 Organize the subjects and site conditions in advance

Next, you should not only determine what to measure but also concretely understand under what conditions you will measure. In 3D surveying of buried cultural heritage, both the characteristics of the subject itself and the features of the site environment are equally important. The difficulty of acquisition varies greatly depending on whether the subject is a wide investigation area, a narrow trench, a deep excavation, highly three-dimensional elements such as stonework or foundation stones, or planar records like soil section faces.

As site conditions, check workspace, surrounding obstructions, sunlight and shadowing, wind, stability of footing, access routes, interference from other work, and responses for rainy weather. Especially for photogrammetry-based 3D reconstruction, strong direct sunlight and deep shadows make shape reproduction unstable and uniform shooting difficult. Conversely, deep excavations or narrow compartments reduce freedom of shooting positions and make it hard to secure necessary overlap. If you decide a method by only looking at the subject, you may not be able to move as assumed on site, causing missing data or delays.

It is also essential to organize the investigation’s progress stages. In records of buried cultural heritage, information to be preserved differs at each stage: before excavation, on detection surfaces, during excavation, after complete excavation, after section exposure, before and after artifact removal, etc. If it is not organized which timing to record what, you may miss the most important state. Especially relationships among features and soil layer changes become harder to grasp over time, so investigation and recording processes must be considered together.

A pre-site visit or quick check is effective here. If parts are already exposed, confirm candidate measurement positions, likely blind spots, potential control point locations, and movement routes. Even if much remains unexposed, knowing the dimensions and depth of the investigation area and surrounding conditions helps anticipate equipment placement and shooting traffic flows. While improvisation on site is unavoidable in 3D surveying of buried cultural heritage, inadequate pre-organization makes that improvisation ad hoc. Organizing the subjects and site conditions beforehand lays the foundation for stable acquisition.

Step 3 Decide accuracy standards and how to handle coordinates

To establish 3D surveying as a reliable record, it is essential to clearly define accuracy standards and how coordinates will be handled. Starting work with ambiguity here can produce visually coherent 3D models that nonetheless fail to align with drawings or other data and are therefore impractical. On site, absolute coordinates may be required in some cases, while in others it may be more important to stably preserve relative positional relationships within the investigation area. First, confirm among stakeholders the level of positional accuracy required for this record.

For instance, if you aim for cross-year comparisons, overlaying with other survey results, integration with plan drawings or topographic maps, or consistency with future re-surveys, coordinate consistency is highly significant. Conversely, for short-term survey records or primarily single-feature shape preservation, designing to prioritize relative accuracy can be more rational. The problem is realizing afterward that “we actually wanted to overlay with other drawings” or “we should have made it comparable later.” To prevent such rework, translate the intended uses and precision requirements identified at the purpose stage into coordinate design.

Decide on control point placement and how to connect to known points at this stage. Depending on the site, existing survey benchmarks may be usable, or it may be more practical to establish site-specific control points. The important thing is to standardize who uses which reference, when it will be checked, and how it will be recorded. If names, positions, intended uses, measurement methods, and verification methods for control points are ambiguous, discrepancies tend to arise in multi-day surveys or operations with multiple staff. If temporary relocation of control points on site is unavoidable, keep a traceable history.

Also, think of accuracy not only numerically but in terms of fit to the intended use. Demanding unnecessarily strict accuracy increases on-site burden and destabilizes the whole process; conversely, underestimating required accuracy makes post-processing correction and explanation difficult. The accuracy needed for overall comprehension and the accuracy needed for detailed verification are not necessarily the same. Rather than applying a uniform standard across the entire site, it is more practical to organize required levels by subject and use. Coordinates and accuracy may seem technical, but they fundamentally affect the usability of deliverables. By settling this first, subsequent method selection and quality checks are less likely to waver.

Step 4 Design measurement methods and a photography plan suited to the site

In 3D surveying of buried cultural heritage, more important than which single method to use is how to combine methods suited to site conditions. Some approaches are better for recording wide surfaces, some for capturing details, and some for quickly covering the whole area. A fail-safe approach is not to seek a panacea method but to design methods and procedures according to the subject’s nature and the intended deliverables.

For example, on wide planar exposure surfaces, it is important to plan shooting traffic flows that make it easy to understand overall positional relationships. In contrast, deep features or highly terraced terrain are often insufficiently captured from overhead alone and require acquisition from oblique and side directions. When stonework or three-dimensional structures are involved, the degree to which you can capture shadowed or near-backside areas, not just the visible faces, differentiates outcomes. It is not simply that narrow sites are easy and wide sites are difficult; whether lines of sight can wrap around and whether acquisition can be done under uniform conditions matters.

In photographic planning, focus on securing overlap and avoiding blind spots. A common on-site mistake is assuming an adequate number of images were taken when in fact many are from similar directions. That results in insufficient parallax for 3D reconstruction. Conversely, overemphasizing parallax and producing incoherent shooting patterns destabilizes data connectivity. The important point is to maintain a consistent overlap while arranging continuous traffic flows that surround the subject. For significant elevation differences, deliberately separate shots for upper and lower layers and for near and mid-range scenes.

The order of shooting and measuring also matters. Coordinate the sequence relative to excavation, cleaning, artifact removal, drafting, and other processes to avoid missing the most valuable recording state. If you postpone all measurement to the end of fieldwork for convenience, important conditions may already have changed. Recording buried cultural heritage is not only about preserving tidy states but also about retaining investigative progress itself at the necessary granularity. Therefore, decide which stage of which process to record in conjunction with measurement methods.

Additionally, prepare contingency plans. Weather deterioration, equipment malfunctions, sudden changes in light conditions, and access restrictions are common. Therefore, separate the minimum recording scope that must be secured from additional ranges desirable if time allows; this simplifies on-site decision-making. Since ideal conditions seldom align on investigation sites, realistically design measurement methods and a photography plan suited to the site and approach the work with priorities—this helps prevent failure.

Step 5 Enforce recording rules on the day of measurement

To stabilize on-site 3D surveying, enforcing recording rules is often more important than technical skill. This is because for buried cultural heritage, it is essential not only to acquire data but to be able to correctly interpret its meaning later. If you cannot trace which point was measured when, under what conditions, and for what purpose, the data’s value drops significantly. Especially when surveys span multiple days, areas, or staff, naming and recording method consistency determine deliverable quality.

First, consistently record subject names, area names, dates, process stages, data collectors, reference standards used, and supplementary notes according to a predetermined rule. Ad hoc data naming causes confusion during processing. If many similarly named datasets accumulate, it becomes unclear which recording corresponds to which moment, and there is a risk of mistakenly overlaying data from the wrong day. Although time pressure on site is common, deciding naming conventions and a simple record sheet in advance greatly reduces downstream burdens.

Next, record on-site state changes. Whether before or after cleaning, whether water was sprayed, presence of sheets or temporary materials, before or after artifact removal, and soil surface shaping conditions all affect 3D results and interpretation. Things obvious when seen on site can be impossible to judge from data alone later. Therefore, besides 3D data, succinctly record site conditions. This helps not only in report preparation but also when a different person reuses the data later.

A quick on-site check during the day is also mandatory. Review not only the number of images and measured points but whether blind spots remain, whether major parts are sufficiently captured, and whether control points and markers appear stable. Waiting until post-processing to check is often too late, so incorporate a first inspection on site. For particularly important features or unreproducible stages, leave room to supplement with shots from different angles or re-acquire immediately after capture.

Also, ensure survey on site does not depend solely on the measurement team. Sharing priorities among excavation staff, recording staff, and drafting staff reduces omissions. While 3D records are convenient, they do not replace all traditional records. Decide during on-site communication which information to preserve in 3D and which to supplement with conventional records. Enforcing on-the-day rules may seem mundane, but it is one of the most practical elements that support an operation that avoids failures.

Step 6 Perform data processing and quality checks in stages

After on-site acquisition, you may be tempted to process everything at once into final deliverables, but to prevent failures it is safer to proceed with processing and checking in stages. In 3D surveying of buried cultural heritage, acquisition volumes tend to be large and the meaning of data differs by process stage, so insufficient organization during processing leads to quality degradation. The key is to refine while checking, not to aim for a finished product from the start.

First, preserve raw data. Shooting images and measurement data should always be backed up before organization so you can work without altering the original data. Data that seemed unnecessary on site may later help fill gaps. Next, organize by area, date, and process stage and make processing units clear. Combining everything at once makes consistency checks difficult and causes errors to be hard to trace.

In the initial processing stages, check not only whether shapes are reproduced but whether they meet the purpose. A visually pleasing model may still fail to show necessary sections, may obscure dimensional sense, have ambiguous soil layer boundaries, or make feature junctions hard to discern. Quality checks therefore must consider practical usability in addition to technical success. Verification viewpoints differ depending on whether the deliverable is for report figures, research records, or public display.

Also, perform coordinate and reference consistency checks early. Discovering mismatches later expands the scope of corrections. By checking agreement with control points, alignment with existing drawings, and connectivity of data acquired on multiple days at each stage, you can avoid major rework. Pay attention to handling noise and unwanted elements too. Reflections of workers, temporary materials, sheets moved by wind, and areas of strong shadow are not just aesthetic issues but affect interpretation. Over-cleaning can erase traces of site conditions.

In quality checks, do not rely solely on the eye of one person. Those who acquired the data know the site but may overlook things from familiarity. Involving people with different perspectives, such as drafting or report staff, improves evaluation of practical usability. 3D surveying of buried cultural heritage is not complete when a model appears in processing software; it is only successful when it makes sense as a record and can be used downstream. Therefore, an operation that incorporates staged processing and verification is necessary.

Step 7 Organize with an eye toward post-delivery use

When thinking about carrying out 3D surveying without failure, people often imagine only on-site acquisition, but practically it is only a success when post-delivery handling is considered. Acquired 3D data do not fully realize their value simply by being collected; depending on how they are organized, they may be used or left unused. Especially for records kept across fiscal years or referenced by multiple departments, it is important that they are searchable, understandable, and extractable in needed formats.

First consider the composition of deliverables. Along with the 3D data itself, provide subject lists, acquisition dates, process stages, coordinate information, control point details, processing conditions, and accompanying documents explaining intended uses—these make reuse easier. A very common practical problem is that when personnel change, the contents become incomprehensible. Organize so that it is clear which area and moment a dataset corresponds to, what level of accuracy to treat it with, and which drawings or reports it corresponds to.

Balance preservation and usability as well. High-resolution raw data have archival value but can be difficult to view and share as-is. Conversely, overly lightweight viewing data cannot support future detailed analysis. Therefore, prepare datasets for long-term archiving, daily viewing, and derivative deliverables convenient for drafting or explanation, dividing roles accordingly. Records of buried cultural heritage often become meaningful for future research or comparison, and uses not anticipated at the time may arise later.

Also, concretely envision scenarios for 3D data use to clarify how to organize them. For example, sharing in on-site review meetings, creating figures for reports, resident briefings, preservation records, educational exhibits, or future comparisons each require different extract and display methods. Delivering data without considering use risks them languishing in storage. For practitioners, ensuring data remain usable is most important.

Finally, leave feedback that can be applied to future projects. Record which methods were stable, where time was consumed, under which conditions missing data occurred, and which deliverables proved useful on site or in reports—this improves accuracy and efficiency in subsequent cases. 3D surveying of buried cultural heritage is not completed by a single successful instance but is refined through accumulating site-specific experience. Procedure design that includes post-delivery organization and utilization planning contributes to practical operations that avoid failures.

Summary

To carry out 3D surveying of buried cultural heritage without failure, do not focus only on equipment or processing techniques; instead, organize the entire flow from setting objectives through organizing site conditions, designing accuracy and coordinate systems, selecting methods, establishing on-the-day recording rules, staged processing and verification, to post-delivery use. Because records often capture temporary states that are hard to reproduce, pre-site preparation and on-site decision rules have an outsized impact on outcomes.

In sites prone to failure, operators may be tempted to rely on experience and intuition, but stabilizing operations in practice requires procedures that maintain a consistent standard regardless of who is assigned. The seven steps introduced here are effective not only for sites introducing 3D surveying for the first time but also for those already conducting surveys that struggle with inconsistent outputs and rework. By clarifying purpose and deliverables, understanding site conditions, defining required accuracy, establishing measurement and recording rules, and progressing processing and verification in stages, 3D surveying becomes not merely visually appealing records but practical investigational assets.

Moreover, in 3D surveying of buried cultural heritage it is important not only to record features and artifacts in three dimensions but also to stably capture the overall positional relationships on site. In situations where you want to efficiently confirm the investigation area’s position, the coordinates of recorded targets, and consistency with existing drawings or other outputs, how position information is handled affects operational ease. In such cases, utilizing LRTK—a smartphone-mounted high-precision GNSS positioning device—can facilitate on-site coordinate confirmation and recording efficiency. Creating an environment that enables smooth management of surrounding position information is also effective for improving the overall quality of 3D surveying. If you want to make recording work more reliable and more practical, consider not only refining 3D surveying procedures but also adopting high-precision position confirmation measures like LRTK to raise the quality of on-site operations.