4 Tips for Capturing Pre-Construction Photos of Solar Power Plants Using Drone Surveys

Pre-construction photographs of solar power plants are not merely record photos; they are important materials for later confirming the pre-development terrain, existing structures, drainage conditions, surrounding environment, and the state of the construction area. Especially for solar power plants that include large sites or sloping land, photos taken only from the ground often fail to preserve the overall picture, making it difficult after construction to explain what the original condition was. What is effective, therefore, is recording pre-construction photos using drone surveying. By keeping aerial overview photos and continuous shooting data, it becomes easier to compare before and after construction, share information among stakeholders, and support future operation and maintenance.

Table of Contents

• The Importance of Retaining Pre-Construction Photos at Solar Power Plants

• Tip 1 Organize the purpose of the shoot and clarify the scope that should be recorded.

• Tip 2: Photograph from an angle that shows the terrain and drainage conditions

• Tip 3 Make location and timing consistent so they can be compared later

• Tip 4: Organize not only photos but also survey data

• Precautions when using pre-construction photographs

• Summary

The purpose of retaining pre-construction photos at solar power plants

In the construction of solar power plants, how specifically the pre-construction condition is documented has a major impact on subsequent inspections and on preventing problems. Once work begins, vegetation clearing, earthworks, drainage ditch installation, pile driving, mounting-structure installation, and cable-route construction quickly change the appearance of the site. It is not easy to accurately describe later, from memory alone, the terrain and ground-surface conditions once they have been altered.

If pre-construction photos are insufficient, the information available for judgment becomes limited when it appears that water flow has changed after construction or when you want to distinguish between pre-existing deterioration and changes caused by the work. For example, small slope failures that existed before construction, cracks in existing roads, clogged drainage channels, vegetation near boundaries with adjacent properties, and the condition of temporary access routes all become harder to confirm after work has begun. By recording these with photographs before construction, it becomes easier to share the situation among stakeholders and to use the photos for explanations at a later date.

Traditional ground-level photographs are effective in that they allow you to get close to the subject and capture fine details. However, at sites with large areas and many elevation changes and blind spots—such as solar power plants—ground photos alone can make it difficult to grasp how the entire site connects. It can also be hard to tell from photos alone where the photographer was and which direction they were facing. This is especially the case at sites where similar grassland or pre-development slopes continue, where the positional relationships between photos tend to become ambiguous.

Using drone surveying allows you to obtain an overhead overview of the entire site, making it easier to understand terrain undulations, drainage directions, and positional relationships with existing facilities. By organizing photos taken along fixed routes and at consistent altitudes, you can preserve the pre-construction condition as surface data. Furthermore, when combined with geotagged photos, orthomosaic images, and point cloud data, the images become more than mere keepsakes and can be handled as record materials usable for construction management and maintenance.

However, photographing with a drone does not automatically produce useful records. If you simply shoot widely without deciding on a purpose, you may not capture the necessary areas, the shooting times may be inconsistent and difficult to compare, and organizing the photos later can take time. To make pre-construction photos useful, it is important to think in advance about what the photos are meant to document, who will use them in which situations, and how they will be stored.

The value of pre-construction photographs at a solar power plant does not end immediately after construction. There are many occasions years later when you may want to look back at past conditions—inspections after commissioning, checking for drainage issues, confirming changes to slopes or site boundaries, assessing vegetation growth, and considering expansions or renovations. If you keep careful records before construction, they will be easier to use as reference material for future decision-making.

Tip 1 Organize the purpose of shooting and clarify the scope that should be recorded

The first tip when capturing pre-construction photos with drone surveying is to clarify the purpose of the shooting. At a solar power plant site, photographing the entire site is important, but that alone is not sufficient. Depending on what the pre-construction photos will be used for, the scope, angles, level of detail, and organization method will differ.

Common purposes include comparisons before and after construction, explanations to neighbors and landowners, internal reporting, confirmation of the work scope, recording the condition of existing structures, understanding the current state of drainage and slopes, and checking before and after tree removal or land development. If you start photographing with these purposes mixed together, you may end up with many photos but still lack images of necessary locations. First, organize the information you want to preserve before construction and make sure it can be verified by photos.

At a solar power plant, not only the area where generation equipment is installed but also the surrounding conditions are important. Site boundaries, access roads, planned material storage areas, temporary roads, existing drainage channels, adjacent farmland and woodlands, existing fences, retaining walls, slopes, and locations near rivers and waterways are all worth preserving in their pre-construction state. Even places that construction itself does not directly enter can be affected by vehicle traffic or temporary works, so include them in the photographic coverage as necessary.

When determining the scope of photography, it is easier to organize if you cross-reference the design drawings and construction plans and separate areas that will change due to construction from those that must not change. Areas such as the planned panel installation area, around pile locations, planned site development areas, valleys and catchment areas related to the drainage plan, and sites planned for on-site roads are locations whose conditions are likely to change as a result of construction. On the other hand, site boundaries, adjacent properties, existing roads, and nearby waterways are places you will want to retain as records showing pre-construction conditions.

In drone surveying, combining wide-area overhead shots with oblique shots at key points is effective. Wide-area photos make it easier to grasp the overall shape of the site and its relationship to the surroundings. Oblique photos, taken from angled perspectives, play a complementary role by revealing information that is hard to discern from directly overhead alone, such as slope heights, the vertical profile of existing structures, the density of tree growth, and the appearance of roads and drainage channels. Relying solely on overhead photos or solely on oblique photos can leave you lacking information you may want to check later.

Also, before shooting, you should consider how much detail needs to be recorded. If the objective is to capture an overall view of the site, wide, continuous shooting is important. On the other hand, if you need to document cracks in existing structures, blockages in drainage channels, or the conditions around boundary markers, it is more reliable to also use ground photographs and low-altitude close-up shots. Drone surveying is strong for gaining an overall picture, but verifying the condition of fine details is affected by shooting conditions and resolution. Depending on the information required, it is essential to plan on the assumption that ground photos will be combined.

Once you have decided on the subjects to be photographed, preparing a written list of shooting items in advance to prevent omissions in the record makes it easier to use in practice. For example, organize the items to check such as the overall site view, access routes, boundary areas, drainage channels, slopes, planned development area, planned tree‑clearing area, existing structures, surrounding roads, and points of contact with adjacent properties. This reduces variation in on‑site judgments and lowers the risk of discovering omissions after the photos have been taken.

Pre-construction photos are not materials that only the person who took them should understand. Designers, construction staff, managers, clients, partner companies, and maintenance personnel may all view them later. Therefore, it is important when photographing to be mindful of whether a third party can understand the location and condition. By clarifying the purpose and scope in advance, photos become record materials that can be used for explanation rather than merely a large volume of data.

Tip 2: Photograph from an angle that clearly shows the terrain and drainage conditions

In pre-construction photos of solar power plants, it is important to clearly document the topography and drainage conditions. Solar power plants may be planned on sites with a variety of conditions, such as former forest land, reclaimed land, fallow land, slopes, and valley terrain. Because there are many situations where you will want to check water flow and changes to the ground surface after construction, carefully recording the pre-construction topography makes later decisions easier.

Top-down photography is well suited to understanding the extent of a site and the placement of structures. Boundary lines, roads, drainage channels, the distribution of trees, and traces of existing land modification can be seen in plan view. By conducting continuous drone surveying and stitching and organizing the photos, the entire site becomes easy to handle like a single map. As documentation for an overview of the current conditions before construction, top-down photography is indispensable.

On the other hand, with only overhead photographs, it can be difficult to discern the steepness of slopes, the height of steps, the condition of slope faces, and the directions in which water is likely to flow. This is especially important at solar power plants, where it is crucial to know where rainwater will collect and where it will flow off-site. Slight undulations on the ground surface, the depth of drainage channels, and the relationship between the slope crest and toe can sometimes be easier to understand from photos taken at an oblique angle.

Therefore, for pre-construction photos it is effective to combine an overhead bird’s-eye view with oblique-angle situational photos. For oblique shots, be mindful of directions such as looking down from the higher side of the site toward the lower side, along the direction of drainage flow, from the side to check the slope face, and from the access road to survey the entire site. This makes it easier to explain the connectivity of the pre-construction terrain and the routes that water is expected to take.

Locations related to drainage should be given high priority for photographic documentation. Existing side ditches, unlined channels, catch basins, entrances and exits of culverts, valley lines, places suspected of having springs, low-lying areas where water tends to pool after rainfall, and spots where water may flow onto adjacent properties are worth preserving in their pre-construction condition. If drainage problems arise after construction, these records can serve as evidence to determine whether they stem from pre-existing topographical conditions or changes caused by the work.

However, drainage conditions cannot always be judged solely from drone photos. Even if the shooting day was clear, different flow patterns may occur during rainfall. Also, waterways covered by vegetation or drainage routes made shallow by sediment can be overlooked in aerial photos alone. Therefore, while using drone surveys to grasp the overall situation, it is important to verify necessary locations on the ground and supplement with photos and notes.

When recording terrain, the pre-development surface irregularities and vegetation conditions are also important. In areas where vegetation is dense, the ground surface can be difficult to capture in photographs. Locations covered by trees or tall grasses require caution; do not judge ground conditions solely from photos. Even if you realize after shooting that "the grass obscures the view," once clearing or construction begins it may be impossible to reshoot the original condition. If necessary, consider recording separate photographs: one documenting the vegetation before clearing and another documenting the ground surface after clearing.

When deciding shooting angles, it's practical to use as a criterion whether someone viewing later can imagine the site's elevation differences. For example, photos taken from the highest point on the site looking toward the lower area, photos looking up at the slope from the low side, and oblique photos taken while circling the site's perimeter help convey the site's three-dimensionality that is hard to understand from plan drawings alone. Pre-construction photos are also materials that preserve the on-site sense that survey results alone can't convey.

Also, attention must be paid to the time of day when photographing. Depending on the sun's position, strong shadows can make surface irregularities easier to discern, but conversely can make important areas difficult to see in shadow. At solar power plants, even before mounting structures are installed, shadows from trees and the surrounding terrain can affect photographs. It is desirable to avoid times when shadows become too long and directions that are prone to blown-out highlights from backlighting, and to photograph under conditions where the necessary areas can be clearly interpreted.

Pre-construction photos from drone surveys are not merely intended to produce attractive aerial images. It is important that they show the relationships between topography, drainage, boundaries, existing features, and the planned construction area. By being mindful of angles that will be useful for later assessment—not just taking visually appealing shots—you increase their practicality as pre-construction records.

Tip 3 Align locations and timing so you can compare later

To use pre-construction photographs as comparison materials in the future, it is important to make the shooting positions and timing as consistent as possible. In solar power plant construction, photos may be taken at multiple stages, such as before construction, after site formation, after pile driving, after racking installation, after panel installation, after completion, and during inspections after operations begin. If the position and orientation of the pre-construction photos differ greatly from those of later photos, it becomes difficult to compare changes.

The advantage of drone surveying is that it makes it easy to capture images along consistent routes and altitudes. If you decide the flight route in advance, it becomes easier to obtain photographs under similar conditions before and after construction. Even if it is difficult to make the conditions exactly the same, aligning the survey area, flight altitude, photo orientation, and key capture points can greatly improve the ease of comparison.

When taking pre-construction photos, it is useful to photograph with reference points in mind. For example, use landmarks that will be easy to identify after construction, such as the corners of the site, the starting point of access roads, connection points to existing roads, areas around boundary markers, confluences of drainage channels, edges of slopes, and existing structures. Even if aerial photos alone make it difficult to determine locations, having these landmarks visible will make it easier to organize the photos later.

The timing of when photos are taken also affects how easy they are to compare. If the season differs greatly between before and after construction, the condition of vegetation, the appearance of the ground surface, shadow lengths, and how rainwater lingers will change. At solar power plants, vegetation growth or leaf fall can make the same spot look very different. When keeping pre-construction photos, recording the shooting date, weather, ground wet/dry conditions, and time of day will make it easier to explain the context when comparing them later.

Conditions after rain in particular can be useful for checking drainage and low-lying areas. However, flying immediately after rain requires attention to safety, protecting the aircraft, and ensuring visibility. Rather than forcing photography in poor conditions, it is practical to keep separate records as needed: standard records taken in fine weather and post-rain inspection records. Clearly indicating which condition a photo documents makes it easier to avoid misunderstandings later.

Location information embedded in photo data is useful for aligning images. However, the location information in ordinary photographs alone does not necessarily allow the precise judgments required for construction management. When accurate positional comparisons are required, the data must be organized while verifying consistency with on-site reference points, control points, and survey results. If you want to utilize drone survey results overlaid on design plans or construction drawings, you need to plan according to the accuracy required on site.

To make photos easier to compare, it is also important to increase the reproducibility of shooting. On sites where the photographer changes each time, shooting methods tend to vary. If, before construction, you decide which areas to shoot and from which directions, from what height to take overall photos, and from which directions to take key oblique shots, later stages can be photographed using the same approach. Linking the drone survey flight plan with the site photo shooting rules makes it easier to maintain consistent record quality.

Also, for comparison, photo file names and folder organization cannot be overlooked. When the number of photos increases, it can take time just to find the ones you need. By clearly organizing the shooting date, site name, shooting area, construction stage, and shooting direction, stakeholders can immediately access the photos they need. Even if you remember the contents of pre-construction photos right after shooting, that memory fades after several months or years. It is important to organize them with the assumption that they will be used later.

When comparing before-and-after construction photos, differences in how the photos appear can lead to misunderstandings. For example, merely differing shooting altitude can make the same channel width or the slope of a bank look different. If the shooting direction is reversed, the way shadows fall and the sense of depth also change. For photos used as comparison materials, it is important to take them under as similar conditions as possible, and if conditions differ, to be able to explain those differences.

Pre-construction photographs of a solar power plant are most effective when kept not only immediately before work begins but also progressively from the planning stage.

If you photograph the same area at each milestone where conditions change—before and after clearing, before and after earthworks—you can track how the site evolves. This is useful not only for construction management but also for later maintenance and for evaluating potential renovations. Rather than a one-off pre-construction shoot, designing drone surveying as a time-series record that can be compared over time is the key to making the most of it.

Tip 4 Organize not just photos but also survey data

If you are keeping pre-construction photos from drone surveying, it is important not only to store the photos individually but also to organize them as survey data. At solar power plant sites the number of images tends to be large, and if you simply put photos in a folder you may later be unable to tell which photo corresponds to which location. Rather than leaving photos in a state where you can only vaguely understand them by looking, organizing them so the location, extent, date, and intended use are clear will increase their value as documentation.

Representative methods for organizing survey data include geotagged photographs, orthophotos, elevation data, point cloud data, and overlay materials with drawings. It is not necessary to produce every type at every site, but it is important to select the deliverables required according to the purpose. If the goal is to gain an overall understanding before construction, orthophotos are useful. When you want to check terrain variations or changes before and after earthworks, data that include elevation information are effective. If you want to preserve the three-dimensional condition of existing structures or slopes, point cloud data can be helpful.

However, the quality of drone survey results can vary depending on imaging conditions and processing methods. In areas with dense vegetation, it may be difficult to accurately represent the elevation of the ground surface. Water surfaces, highly reflective materials, monotonous ground surfaces, and areas with strong shadows can also affect data creation. When using pre-construction photographs as survey data, it is necessary to distinguish between the information visible in the photos and the information that can be interpreted as survey results.

For pre-construction records of a solar power plant, organizing them so they are linked to the design drawings and construction plans makes them more useful. Indicate which planned parcel the photographed area corresponds to, which roads or drainage channels it relates to, and which construction section’s pre-construction condition it represents, so that construction and management personnel can easily verify it. By making the materials current-condition documentation that can be cross-referenced with the drawings—rather than mere aerial photographs—you improve the ability to explain the before-and-after construction.

When organizing photo data, it is also important to store original files and processed files separately. Original photos should be kept as the primary record at the time of capture. Meanwhile, images whose brightness has been adjusted for sharing with relevant parties, documents with annotations, and materials overlaid on drawings should be distinguished as processed data. If you cannot tell later which are the original files and which were processed for explanatory purposes, it can cause confusion when making decisions.

Also, notes recording the conditions at the time of imaging are important. Recording the shooting date, the photographer, the weather, wind conditions, the coverage area, the reference points used, whether ground verification was performed, areas that could not be captured, and any blind spots to be aware of will make it easier to understand the meaning of the data later. In particular, because pre-construction photos may be used for future comparisons, it is reassuring to have information that can explain the conditions at that time.

When organizing survey data, it is also important to put it into a format that is easy for people within the company to use. Leaving only specialized processed data may mean that field personnel or managers cannot check it immediately. Providing images for an overall review, verification materials overlaid on drawings, and a structure that allows detailed data to be referenced as needed makes it easier to use in practice. The goal should not be only to create advanced data, but to ensure that the people who need it can check it when they need to.

When storing data, you also need to pay attention to version control. As data accumulates at each stage—before construction, after tree removal, after land development, and after completion—old and new materials can easily become mixed. Include the date and the construction stage in folder and file names so it’s clear which point in time each file represents. Avoid overwriting files and keep a traceable change history to prevent confusion when reviewing materials later.

Furthermore, the pre-construction photos captured by drone surveys also contribute to maintenance. If, after completion, drainage appears to have worsened, slope vegetation has changed, or you want to check shading effects from the growth of nearby trees, comparing with the pre-construction condition makes assessment easier. Data organized so that future maintenance personnel can understand it also supports the long-term operation of the power plant.

To treat pre-construction photos as survey data, it is important to consider the entire workflow—from capture, processing, organization, sharing, to storage. Rather than stopping at capture, preparing them as materials usable for site management will further enhance the effectiveness of drone surveying.

Precautions When Using Pre-construction Photos

When using drones for surveying to record pre-construction photos, there are several points to be aware of. First and foremost is operating with consideration for safety and legal compliance. The checks required for drone flights differ depending on the location, airspace, flight method, and surrounding environment. Planned sites for solar power plants are often in mountainous or suburban areas, but there may also be nearby houses, roads, railways, transmission lines, communications equipment, or airport-related restricted zones. Before filming, it is necessary to confirm whether flight is permitted, any required procedures, and how to ensure safety on site.

On-site safety management is also indispensable. Land before construction can include areas with dense vegetation and poor footing, steep slopes, muddy spots and steps, or existing structures that have deteriorated. Not only the person operating the drone but also assistants and on-site inspectors should be able to move safely, so confirm in advance the takeoff and landing locations, entry areas, vehicle routes, and any potential interference with surrounding work. Drone surveying is useful for checking places that are difficult to access, but because people may still need to enter the site for flight preparations and visual checks, it is important not to omit safety management.

If the photographed area may include adjacent properties, houses, roads, vehicles, or people, attention must also be paid to privacy and information management. Because photos taken before construction may be shared both inside and outside the company, care should be taken to ensure that unnecessary personal information or unrelated facilities do not appear. If necessary, limit the scope in materials prepared for sharing or remove parts that are not needed for explanation. However, it is desirable to distinguish between the storage of original data and the editing of shared materials, and to organize them so as not to compromise the reliability of the records.

Also, it is important not to overestimate what drone photos show. While a great deal of information can be seen from above, you cannot confirm what lies beneath vegetation, behind structures, inside drainage channels, or the conditions underground. Something may appear fine in photos but, when inspected on the ground, a waterway may be clogged or a slope may have small cracks. Drone surveying is a means to streamline on-site inspections and cannot be used to make all judgments in place of necessary ground verification.

Pay attention to the quality of the photos. Out-of-focus photos, blurred photos, photos with extreme exposure, photos where the subject is obscured by shadows, and photos with intervals between shots that are too large can become difficult to use later. Since the condition before construction can often only be photographed once, it is important to check the data immediately after shooting and, if there are omissions or defects, retake them where possible. In particular, promptly check for any missed shots of the edges of the site, areas near boundaries, drainage routes, and existing structures.

When sharing results produced by drone surveying with stakeholders, explaining how to read the materials can help prevent misunderstandings. For example, orthophotos are planar, top-down materials, and impressions of elevation differences may need to be confirmed using separate data. Elevation data can be affected by capture conditions and processing settings. The conditions shown in a photograph do not necessarily reflect the actual condition of the ground. Sharing how the materials should be used and their limitations makes it easier to avoid overly definitive conclusions.

Pre-construction photos are valuable not only to the client and contractor but also to maintenance personnel. Therefore, it is desirable to organize them on the assumption that the data will be handed over upon project completion. If they are stored only with the construction staff, they may not be found when needed in the future. Clarifying the storage location, file structure, contents of verification materials, and the whereabouts of the original data will make them records that can be used over the long term.

Additionally, it is useful to keep captions and annotations for photos, even if brief. Photos alone may not make clear what was intended at the time of shooting. For example, simply adding descriptions such as "existing drainage channel on the north boundary," "pre-construction conditions at the planned access road," "vegetation conditions at the top of the slope," or "areas of rainwater accumulation in low-lying sections" can greatly change the understanding of someone viewing them later. Because drone surveys generate large amounts of data, attaching annotations that indicate the purpose to important photos and deliverables makes them easier to use.

What is important when using pre-construction photos is to treat the captured data not as infallible evidence but as objective material for explaining site conditions. Photographs have strong explanatory power, but impressions can change depending on shooting conditions and perspective. Verifying them, as necessary, against drawings, survey results, field notes, and ground-level photos leads to safer, more practical decisions.

Summary

Capturing pre-construction photos of solar power plants through drone surveying is an important practice that aids before-and-after comparisons, sharing on-site conditions, and future maintenance. On sites that include large areas or sloped terrain, ground-level photos alone can make it difficult to preserve the overall picture and spatial relationships. By utilizing drones, you can clearly record a bird’s-eye view of the entire site, drainage routes, the positional relationships of boundaries and existing structures, and the pre-development terrain conditions.

The key to effectively preserving pre-construction photographs is to first clarify the purpose of the photos and define the areas that should be documented. In addition to an overall view of the site, decide in advance which locations you may want to check later—such as access routes, boundaries, drainage channels, slopes, existing structures, and points of contact with adjacent properties—so it becomes easier to avoid missing shots.

Next, it is important to photograph from angles that reveal the terrain and drainage conditions. Photos taken directly overhead are useful for grasping the overall layout, but slopes, steps, and water flow are often easier to understand in oblique shots. By combining overhead and oblique photos and, when necessary, supplementing them with ground-level shots, you can preserve a more three-dimensional record of the site conditions.

Also, to allow later comparison, it is important to match as closely as possible the shooting position, orientation, elevation, and timing. If you can shoot before construction, after earthworks, after completion, and during inspections using the same approach, it becomes easier to confirm changes. Recording the shooting date, weather, and shooting conditions and establishing rules for organizing photos will make the materials easier for stakeholders to use later.

Furthermore, rather than simply storing photos individually, it is useful to organize them as survey data. By utilizing geotagged photos, orthophotos, elevation data, point cloud data, and materials that overlay drawings according to purpose, you can describe pre-construction conditions more concretely. Separating raw data from shareable materials and organizing them by construction stage also makes long-term management easier.

However, drone surveying is not infallible. Photographs alone may not be sufficient to determine conditions beneath vegetation, inside drainage channels, or underground. In practice, safety management, legal compliance checks, privacy considerations, and verification of data quality must be carried out and combined with necessary on-the-ground inspections.

Pre-construction photographs of a solar power plant are important records that can only be captured before work begins. To avoid later regret of "I wish we had taken them," it is important to consider the purpose, scope, angles, comparisons, and data organization together. To preserve the pre-construction condition in a clear, easy-to-use, and long-lasting form, it is essential to operate drone surveying in combination with site records, plan verification, ground inspections, and data storage.