Four Precautions and Countermeasures to Avoid Failure in Photogrammetry of Cultural Properties

Interest in photogrammetry is increasing year by year in the fields of cultural property documentation, investigation, restoration planning, and public utilization. The major appeal is that shapes, dimensions, and surface conditions that could not be fully captured by traditional hand-drawn records or flat photographic records can be reconstructed in three dimensions from multiple photographs. Because it can produce three-dimensional data that can be reviewed later while keeping the burden on site relatively low, it is a very powerful method for practitioners.

On the other hand, photogrammetry of cultural properties is not a matter of simply taking a lot of photos and expecting success. Unlike measurements of general structures or terrain, cultural properties involve unique conditions such as difficulty of redoing work, restrictions on contact, constraints of the working environment, long-term preservation of records, and the need to enable future comparative investigations. As a result, even if everything appears fine immediately after shooting, failures often occur in later stages: “necessary parts cannot be reproduced,” “dimensional reliability is insufficient,” “usable as a record but not for investigation,” or “saved data is difficult to utilize in the future.”

Practitioners searching for information under “cultural property photogrammetry” are likely less interested in a technical overview and more in what to watch for in the field to prevent failure, and what to confirm at the ordering and planning stages. Each cultural property differs in condition and value, and it is often difficult to apply the same method across the board. That is why pre-arrangement and a coherent approach to shooting, measurement, and preservation are important.

This article organizes and explains the common failures in photogrammetry of cultural properties into four particularly important practical precautions. For each, concrete countermeasures are provided so you can review the process consistently from planning through shooting to data management. Whether you are starting photogrammetry of cultural properties for the first time or have done it once but encountered issues, this practical guide aims to serve as a decision-making framework and will dig into details from a practitioner’s perspective.

Table of Contents

• Reasons why failures are likely in photogrammetry of cultural properties

• Precaution 1: Do not leave the recording purpose and required deliverables ambiguous

• Precaution 2: Do not leave the shooting plan to on-site judgment

• Precaution 3: Do not underestimate considerations of accuracy

• Precaution 4: Do not postpone post-delivery preservation and utilization

• How to proceed to successfully carry out photogrammetry of cultural properties

• Summary

Reasons why failures are likely in photogrammetry of cultural properties

The main reason failures are likely in photogrammetry of cultural properties is insufficient preparatory organization before the shooting itself. Photogrammetry is a method that reconstructs shapes from photographs, so the way photos are taken greatly affects the quality of the deliverable. However, at the site, photographing is often perceived as “just take more photos for now,” and investigations can proceed without clarity on survey objectives, required accuracy, recording extent, or how the data will be used in later stages. As a result, even if the number of photos is sufficient, the desired information can be omitted.

Unlike ordinary buildings or civil engineering structures, cultural properties are often difficult to touch directly. You may not be able to approach them, erect scaffolding, change lighting, move them, or have ample working time; visitor circulation may not be obstructed. Outdoor sites are further influenced by weather, sunlight, shadow patterns, vegetation, and surrounding obstructions. Even indoors, reflections, dark areas, confined spaces, or shooting through display cases can combine to affect accuracy. If these constraints are not taken into account and you approach the site with general-photography instincts, the resulting data is likely to be unusable later.

Also, for cultural properties the act of “preserving” can itself become the goal, and measurement can begin without clarity on what and at what granularity should be preserved. For example, the required photographic method and reference information differ depending on whether the aim is to preserve the overall shape, compare areas of deterioration, check differences before and after restoration, or produce drawings. Different objectives require different model density, surface detail to be reproduced, color handling, dimensional reliability, and alignment methods. If this organization is insufficient, the three-dimensional data produced may be “viewable” but not robust enough for practical use.

Another frequently overlooked point is that photogrammetry does not conclude once shooting is finished. In practice, “record preservation” is only established after post-shooting data organization, confirmation of processing conditions, management of unnecessary photos, model validation, checking coordinates and scale, exporting deliverables, and organizing storage formats. Judging success by impressions on the shooting day can leave gaps and inconsistencies discovered later, leaving only data that are hard to use and without the possibility of returning to the site.

Therefore, in photogrammetry of cultural properties it is important not only to focus on shooting techniques but also to consider pre-design and operational design. The next chapters examine four practical precautions that commonly lead to failure, along with their countermeasures.

Precaution 1: Do not leave the recording purpose and required deliverables ambiguous

The first precaution is not to start with the purpose and required deliverables of photogrammetry left ambiguous. This is the most basic, yet it is often the source of most failures. For cultural property photogrammetry, “creating a three-dimensional model” itself is not the objective. What matters is clarifying why the three-dimensional data are being acquired and who will use them and how.

For example, if the objective is to preserve the overall shape of a cultural property as a record, photographing to prevent omissions of the entire object is emphasized. On the other hand, if restoration or chronological comparison is expected, reproducing the details of specific parts and designing so that the same conditions can be reshot become more important. When considering exhibition or educational use, a visually clear three-dimensional model and natural color may be required, while strict dimensional accuracy can be relatively lower priority. If you want to use the data for drafting or cross-section checks, how scale and coordinates are handled, required resolution, and minimizing blind spots become more important. Even under the single term “photogrammetry,” success conditions vary greatly with purpose.

If the purpose is ambiguous, decisions at the site waver. Shooters cannot decide whether to capture the whole or focus on details. Clients cannot hold evaluation criteria for deliverables, resulting in mismatches after completion. Especially at cultural property sites, where shooting time may be short and access restricted, indecisive shooting easily leads to omissions. Since these often cannot be remedied later, initial organization is extremely important.

As a countermeasure, first put in writing “what you ultimately want to judge.” Clarify a primary purpose such as preservation record, current condition survey, change detection, restoration planning, drafting, or public use. Then break down “what deliverables are necessary to satisfy that purpose.” Determine whether you need only a three-dimensional model, orthophotos, drawings or documents that allow dimensional checks, or data reproducible under the same conditions for chronological comparison; this will make the shooting policy concrete.

Next, clearly define the target coverage. Cultural property documentation can include not only the main object but also the plinth, surrounding terrain, attached components, damaged areas, joints, back sides, and interior spaces. The design of the operation changes significantly based on what is included. It is not uncommon to be satisfied with photographing only the whole and later find that the defective area you wanted to compare was not sufficiently captured. When multiple uses are anticipated, it is effective to separate whole-object recording and focused recording. Planning separate shoots for whole coverage and detail-focused capture helps keep priorities stable on site.

It is also important to consider deliverable formats in advance. Whether you only need to view a three-dimensional model, share still images, or require formats usable in different environments in the future will change the types of data to organize. Since cultural property records are assumed to be used long-term, it is essential to preserve data in a form that is easy to reuse, not just temporarily appealing.

Failures in photogrammetry often start not with shooting technique but with vagueness in purpose setting. Conversely, if purpose and deliverables are clear, the necessary photos, accuracy, and on-site work become apparent. If you want to succeed in photogrammetry of cultural properties, begin by defining not only “what you want to preserve” but “in what usable state you want it preserved.”

Precaution 2: Do not leave the shooting plan to on-site judgment

The second precaution is not to leave the shooting plan to ad hoc on-site decisions. In cultural property photogrammetry, shooting conditions almost determine the outcome. While the ability to adapt on site is of course necessary, entering the site with a weak pre-plan increases the likelihood of omissions, duplications, blind spots, and inconsistent conditions. Even many photos won’t yield a stable model if they don’t connect well.

Pay special attention to cases where no shooting flow is planned to match the object’s shape. Cultural properties are not flat; they often have protrusions and recesses, intricate decorations, recessed spaces, overhangs, and shadowed areas. Shooting only by walking around once leaves parts that appear visible but are not. For sculptures, stone structures, wooden decorations, wall delamination, and terraced remains, frontal photos alone often lack information needed for three-dimensional reconstruction. Overlapping shots from oblique angles, viewpoint differences from above and below, and close-up detail shots are often necessary.

Also, do not underestimate light conditions. Strong surface reflections or major shadow changes by time of day can hinder stable reconstruction. For outdoor cultural properties, morning and afternoon shadow patterns can change so much that the same area looks like a different object. Indoors, spotlights, case reflections, and noise in dark areas can be problematic. Even if the photos look nice to the eye, matching points during processing can be difficult, so do not rely solely on how the site appears.

Moreover, frequently changing shooting distance and focal length is a cause of failure. If you increase close-up photos to capture details or take only distant photos to capture the whole, connections among photos weaken. In photogrammetry of cultural properties, it is important to design both a set of photos that connect the whole and a set that supplements details. Either alone is insufficient; lacking intermediate photos that bridge whole and detail causes parts of the model to collapse or details to float.

A useful countermeasure is to think of the shooting plan in layers before entering the site. First plan photos for overall understanding, then photos to cover each face and component, and finally supplemental shots for priority areas. This helps maintain priorities even when time is limited. Unexpected constraints occur on site, but if you have predetermined the “minimum set of photos to secure,” you can reduce the risk of critical omissions even when time is shortened.

Pre-inspection, checking drawings, and reviewing existing photos are also effective. Knowing where blind spots likely are, which access directions are difficult, and at what times shadows are strong reduces on-day hesitation. Because protective constraints often limit equipment placement and movement at cultural property sites, pre-checks are more valuable than at typical sites.

Additionally, always perform on-site checks after shooting. Don’t just stop when you’ve taken the photos—verify photo continuity, coverage of key areas, and whether there is blur or exposure issues. While fully reproducing post-processing on site is difficult, it is often possible to detect fatal omissions on the spot. Because revisits to cultural property sites are often difficult, incorporate on-site verification time into the schedule.

A shooting plan is not a supplement to technique but a means of quality assurance. In cultural property photogrammetry, relying solely on on-site adaptability has limits. Designing a planned shooting sequence based on object shape, light conditions, accessibility, and information density is the shortest route to preventing failure.

Precaution 3: Do not underestimate considerations of accuracy

The third precaution is not to proceed with vague thinking about accuracy. In cultural property photogrammetry, “a visually appealing three-dimensional model” is not the same as “a model with accuracy sufficient for records or investigation.” Confusing these leads to major problems later. Practitioners should pay particular attention to judging how much dimensional reliability and positional reproducibility the photogrammetric results have for their intended use.

For instance, if the model will only be viewed for exhibition or education, some dimensional error might be acceptable. However, for comparing progression of deterioration, checking consistency with restoration components, reading cross-sections, or comparing with future re-measurements, considerations of scale, coordinates, and reproducibility are crucial. For cultural properties, subtle changes in shape can be meaningful, so “it looks right” is not enough.

A common mistake is to treat a model generated purely from photos as measurement-ready data. If conditions are right, photogrammetry can yield useful measurement results. However, to do so requires scale references, positional references, stable shooting conditions, and model validation. Models produced without these considerations may be useful for relative shape understanding but should be treated cautiously for rigorous comparison or drafting.

When considering accuracy at cultural property sites, it is important not to chase absolute numbers alone but to work backwards from the required accuracy for the intended use. What error range is acceptable? Which parts require accuracy? Is it necessary to reproduce the same standard for future comparisons? Clarifying these reveals the necessary on-site actions. In some cases, designing for high accuracy only in critical parts rather than the entire object is effective.

As a countermeasure, first design scale and positional references in advance. Rather than relying solely on photogrammetry, adding reference information to the object or surroundings increases the credibility of deliverables. Methods vary by site conditions, but at minimum do not leave “what will serve as the standard for dimensions and position” ambiguous. Since cultural properties may restrict installation or contact, consider non-contact reference methods or using the surrounding environment.

Next, validate the completed model. Beyond visual impression, perform basic plausibility checks by comparing known dimensions, checking multiple areas, or comparing data taken under different shooting conditions. The more complex the object’s shape, the more likely localized distortions will appear. Even if the whole looks natural, errors often appear at edges, shadowed parts, or featureless surfaces, so select validation points intentionally.

If future comparisons are anticipated, thinking “it’s fine because it works this time” is insufficient. Record the references used, the rationale for shooting positions, the object coverage, shooting date and time, light conditions, and special notes so that the same standards and conditions can be reproduced in re-measurement. Cultural property records are referenced over long periods, so they must be organized so a different practitioner years later can replicate them.

Accuracy is not a matter only for specialists. Clients and managers should also understand the accuracy requirements for each use. If this is unclear, excessive demands can cause impractical work, or conversely, necessary quality may not be ensured and substandard deliverables accepted. In cultural property photogrammetry, separating visual quality from record quality and designing accuracy that matches the purpose is key to preventing failure.

Precaution 4: Do not postpone post-delivery preservation and utilization

The fourth precaution is not to postpone thinking about preservation and utilization after delivery. In cultural property photogrammetry, attention tends to focus on shooting and model creation, and receiving delivery can feel like the job is done. However, what truly matters is leaving the results in a form usable into the future and making them retrievable when needed. If this is insufficient, three-dimensional data obtained at cost can become untraceable, unreadable, or contextless within a few years.

Cultural property records differ from typical short-term business data. They are not only for immediate use but may be used for future comparisons, re-surveys, checking restoration histories, preparing public materials, and disaster recovery—long-term usability is expected. Thus, merely retaining data is not enough; it must be managed so that later personnel can understand it. In practice, however, it is common to find mixed deliverables—images, models, output files—left in delivery folders without clear correspondence to shooting date, coverage, reference information, and processing conditions.

It is also problematic when delivery formats are biased toward temporary viewing. Attractive viewer formats are convenient, but they alone may be difficult to reuse in the future. For cultural property records, it is important that viewing deliverables be accompanied by source photos, base data, reference information, and explanatory materials properly organized. If it is unclear which photo sets produced which deliverables, what the coverage is, or what moment the data represent, the data cannot be used later for comparison or validation.

As a countermeasure, decide the composition of deliverables in advance. Plan not only the final deliverables but also how to store source data, work logs, descriptions of the target coverage, reference information, and a deliverables inventory. Anticipating what and how to preserve from the beginning reduces confusion at handover. For cultural property photogrammetry, explanatory information accompanying the data is as important as the data itself. Organize it so that a third party can understand it after personnel change.

File and folder naming conventions should not be neglected. Without unified naming for object name, shooting date, part, version, and deliverable type, searching later becomes difficult. Especially for chronological comparison, organization by year and implementation is indispensable. If “previous data exist but it is unclear which parts were taken under the same conditions,” the value as comparative material greatly decreases.

It is also useful to consider how to hold data according to usage scenes. Requirements for format, size, and viewing method differ for investigation, management, sharing, and public use. Trying to consolidate everything into one format can make the data hard to use on site. For example, keep detailed base data in storage but prepare lightweight deliverables for routine checks to make data usable in daily operations.

Above all, do not end with “the data are stored.” Consider where they are stored, who can access them, how update history is managed, and procedures for reuse. Photogrammetry of cultural properties is not a one-off event but part of preservation management. Only by planning for post-delivery preservation and utilization does photogrammetry fully realize its value.

How to proceed to successfully carry out photogrammetry of cultural properties

So far we have reviewed four precautions, but in practice knowing each individually is not enough. To prevent failure you must design the entire flow from planning to post-delivery. A helpful sequence is: first clarify the purpose, then set the target coverage and required accuracy, create the shooting plan, perform on-site verification, conduct post-processing validation, and finally design delivery and preservation.

In the initial purpose clarification, concretely define “why we measure” and “what constitutes success.” Eliminating ambiguity here becomes the basis for all subsequent decisions. In defining target coverage and required accuracy, separate whole-object recording from priority recording and specify the level of reproducibility required for each part. At this stage, consider whether on-site reference information or auxiliary measurements are needed to ensure accuracy; doing so stabilizes later processes.

When creating the shooting plan, build a shooting sequence mindful of object shape, access, light conditions, and time constraints so photos will connect. To avoid confusion on site, categorize shots into minimal necessary shooting, supplemental shots for priority parts, and verification shots. Because conditions at cultural property sites are hard to change on the spot, pre-design strength has a larger impact on quality than on-site adaptability.

On the shooting day, include verification as part of the workflow, not only taking photos. Omissions, blur, exposure differences, shadow bias, and lack of coverage for key parts can often be corrected on site; shortcomings discovered after leaving the site are frequently irrecoverable. The value of on-site verification increases where revisits are difficult.

After processing, verify not only visual completeness but also suitability for intended use. Check whether required parts are reproduced, whether conditions for comparison or drafting are met, and whether there are major inconsistencies with known information. Careful checks at this stage significantly reduce post-delivery troubles and rework.

Finally, in delivery and preservation design, organize data so they can be used continuously. Cultural property records should not be left only on an individual’s device. Structuring them so institutions or organizations can inherit them increases their value. Photogrammetry of cultural properties should be regarded not merely as a measurement task but as the development of an information asset intended for long-term preservation.

Summary

To avoid failure in photogrammetry of cultural properties, do not focus only on equipment or processing techniques; consider purpose setting, shooting planning, accuracy design, and preservation operations as an integrated whole. Pay particular attention to not leaving the recording purpose and deliverables ambiguous, not leaving the shooting plan to on-site judgment, not underestimating accuracy considerations, and not postponing post-delivery preservation and utilization. Addressing these four points already prevents many common failures in cultural property photogrammetry.

Because a cultural property can be damaged, missed, or inadequately recorded and cannot be reproduced under the same conditions, when introducing photogrammetry it is important to consider it not merely as a new recording method but as the foundation for future investigation and preservation management. Plan carefully, capture necessary information without excess or omission, and preserve it in a form that remains useful over time—these factors greatly determine the quality of cultural property records.

Additionally, for stable practical progress in cultural property photogrammetry, consider handling on-site positional and reference information in addition to photographs to increase the credibility of deliverables. When you want to efficiently organize shooting positions, coverage, and related on-site information, using an iPhone-mounted GNSS high-precision positioning device such as LRTK can help link photographic records and positional information. If you want to make cultural property record preservation more reliable and practical, incorporate such simple surveying methods into your photogrammetry planning to improve on-site accuracy and reusability.