4 steps to use drone surveying to assist in confirming land classification of solar power plants

In planning, sale and purchase, operation and maintenance, and consideration of expansion for solar power plants, there are many situations where confirming the land’s cadastral classification is necessary. The cadastral classification is information indicating the type of land on the registry, but it does not necessarily match at a glance the way the site is actually used, the development status, equipment placement, or the condition near the boundaries. In particular for solar power plants, forestland, undeveloped land, miscellaneous land, rice paddies, fields, and land adjacent to residential lots may be involved, and proceeding while leaving an understanding of the current situation ambiguous can lead to misunderstandings among stakeholders and to rework of verification tasks in later stages.

What helps in this regard is visualizing site conditions using drone surveying. Drone surveying is not a procedure for determining the registered land category itself. However, because it can record from the air the overall topography of the solar power plant, the extent of earthworks, panel layout, access roads, slope faces, drainage facilities, and relationships with adjacent land, it makes it easier to streamline the on-site assessment required for land-category confirmation. This article explains four steps to utilize drone surveying for land-category confirmation of solar power plants, presented in an easy-to-understand way for practitioners.

Table of Contents

• Prerequisites to Grasp First When Verifying Land Classification

• Step 1 Compare the registry information with the on-site boundaries

• Step 2: Record current land use with drone surveying

• Step 3: Clarify the differences between land classification and current conditions

• Step 4: Compile into materials that can be shared with stakeholders

• Situations where confirming land classification becomes important at solar power plants

• How to proceed with confirmations without relying solely on drone surveying

• Summary: Land classification checks should start by visualizing the current status.

Essential prerequisites to understand before verifying land classification

When confirming land categories for a solar power plant, it is important to first separate "registered information" and "how the site appears on the ground." A land category is a classification in land registration that indicates the use and nature of the land. On the other hand, at the site you may find a mixture of solar panels, mounting racks, access paths for maintenance, fences, balancing ponds, drainage ditches, slopes, and unused areas, so you cannot directly determine the land category from aerial photos alone.

For example, there are cases where solar power generation facilities are installed on land that is registered as forest or undeveloped land. Also, land that was originally used as farmland may be used as a power plant site after various procedures and land development. Furthermore, when a single power plant includes multiple parcels of land, the land classification may differ by parcel, and there may be discrepancies between the registered land classification and the actual on-site use.

In such situations, it is important to view drone surveying not as a tool to definitively determine land classification, but as a tool for organizing the current on-site information needed to confirm land classification. By overlaying the on-site conditions with registration records, lot-number maps, cadastral maps, land area survey maps, boundary confirmation materials, procedural documents related to development and farmland, past development drawings, and so on, the points that need to be confirmed become clear.

In solar power plants, even if the entire site has been developed, parts of the premises may remain as unused land or leftover slopes. The actual uses are not uniform: areas where power generation equipment is installed, areas used as material storage yards, areas left as grassland, areas set aside for drainage, and so on. When confirming land classifications, these subtle differences in land use must not be overlooked.

Also, verifying land classification is not something that should end with a mere document check. It affects various practical matters such as the sale and purchase of power plants, collateral valuation, maintenance management, expansion, regrading, coordination with adjacent land, and the preliminary arrangements for administrative consultations. If the on-site conditions are not accurately shared, confirmations are likely to arise later, such as “which parcel does this part belong to?”, “what is this land actually used for?”, and “how should we explain the discrepancies between the registered records and the current conditions?”

Therefore, as a starting point for confirming land-use classification, it is important to carefully organize the extent of the subject land, the relative positions of each parcel, the on-site usage, equipment layout, and the conditions near the boundaries rather than immediately drawing conclusions about the land-use category itself. Drone surveying is effective because it allows this situational assessment to be carried out broadly and visually from above.

Step 1 Compare registration records with on-site boundaries

The first step in using drone surveying to help verify land-use classification is to reconcile the registration information with the actual on-site boundaries. Although a solar power plant site may appear to be a single facility, it is often actually divided into multiple land parcels. It is necessary to first determine which parcels include the footprint of the generation equipment, fenced areas, maintenance roads, areas around substation equipment, slopes, drainage facilities, and adjacent unused land.

At this stage, we first check the land lot number, land area, land category, owner, and an overview of rights from the registration records. We also collect the cadastral map, land-area survey map, past survey results, drawings from the time of site development, and the power plant layout plan to organize an overall picture of the subject site. However, paper drawings alone can make it difficult to intuitively determine which on-site area corresponds to which parcel. In particular, for solar power plants in mountainous or sloped terrain, parcel boundaries do not always coincide with fences, access roads, or the extent of site development, so caution is required.

If you carry out drone surveying here, you can check the latest condition of the entire site from above. By producing orthophotos and point cloud data, you can examine the layout and extents of panel rows, walkways, slopes, drainage routes, fences, and boundaries with adjacent land. Overlaying parcel boundary and lot number information on these outputs makes it easier to reconcile land registry information with on-site conditions.

However, the images and point clouds obtained from drone surveying do not legally establish boundaries themselves. They need to be verified in combination with the presence or absence of boundary markers, past boundary confirmations, the contents of cadastral survey maps, records of stakeholders’ attendance, and so on. The role of drone surveying is solely to visualize the on-site conditions and to make it easier to cross-check with the information in the documents.

In practice, you first identify the perimeter of the power plant and then check the relationship between each land parcel’s boundaries and the equipment layout. For example, even if everything within the fence appears to be used as the power plant site, some portions may belong to different parcels, or only access paths and slopes may extend into adjacent parcels. Also, margin areas where panels are not installed may remain, on the land register, as land of a different category.

By carrying out this reconciliation work carefully, the subsequent verification items become clear. You can sort out which parcels' land classifications need to be checked, where there are likely discrepancies between current conditions and registered information, and which parts require additional document review or consultation with specialists. In land classification checks for solar power plants, if the initial scope organization is insufficient, subsequent on-site inspections and document preparation tend to become vague.

When using drone surveying, it is also important to clearly define the target area before the survey. Rather than photographing only the central part of the power plant, plan so you can record the perimeter, adjacent land, access routes, drainage outlets, and the lower and upper edges of slopes. This is because, in land-use verification, it is necessary to understand not only where equipment is located but how the entire property is being used.

Step 2 Record current land use using drone surveying

The second step is to document the current land use through drone surveying. When confirming land classification, it is important to understand how the land is currently being used. In the case of a solar power plant, multiple forms of use can exist within a single site, not only the power generation area where panels are arrayed, but also maintenance roads, grassy areas, slopes, drainage facilities, developed flat areas, undeveloped portions, and open spaces around equipment.

Aerial images help provide an overview of these differences in land use. Ground-level photos can have their views obstructed by rows of panels, fences, and embankments, making it difficult to grasp the relationships across the entire site. In contrast, aerial images produced by drone surveys make it easier to view the overall layout of the power plant and its relationship with adjacent land in a single image.

What's particularly effective for verifying land categories is dividing the land by use and recording each area. Organize areas such as those where power generation equipment is installed; areas used for management access; areas maintained by mowing; areas functioning as drainage facilities; areas that have been developed but contain no equipment; and areas where the natural terrain remains. This classification does not directly determine the land category, but it provides important material when comparing the registered land category with the current conditions.

Drone surveying makes it easier to confirm on-site elevation information. On sloped solar power sites, cut-and-fill, slopes, level changes, and drainage gradients are closely related to actual land use. For example, when the flat area where the power equipment is installed and the surrounding slopes and drainage channels are included in the same land parcel, a point of contention in land-classification checks can be how to organize the overall land use. By using point cloud data and elevation information, it becomes easier to grasp the earthwork conditions that are hard to understand from mere plan-view photos.

Also, when verifying land classification, attention must be paid to the timing of photography. During periods when grass is growing, the ground surface, drainage facilities, and areas near boundaries can become difficult to see. Conversely, immediately after mowing, it is easier to check the topography and structures. Snow cover, deep shadows, and muddy conditions immediately after rain can also affect how the current conditions appear. When conducting drone surveys, it is desirable to choose a time when the condition of the target site can be checked as easily as possible.

When photographing, it's also important not to focus too much solely on the power generation equipment. In surveys of solar power plants, attention tends to go to panel damage, weeds, and equipment inspections, but in land classification checks the primary focus is the land's actual usage. Be sure to consciously record the ground surface under the panels, the width of pathways, any remaining land outside the fence, the location of drainage ditches, connections with adjacent farmland or woodland, and how access roads are handled.

The results of drone surveying are also useful as records that allow stakeholders to verify the same conditions later. Personnel who could not attend the on-site inspection—such as real estate and legal staff, design personnel, and operations and maintenance staff—can discuss while looking at the same images and survey deliverables. Rather than explaining only in writing that "it is being used as a power plant" or "there is some unused land," showing images and drawings makes it easier to reduce discrepancies in understanding.

Furthermore, at power plants that regularly conduct drone surveys, you can compare past site conditions with current ones. If records exist for each point in time—such as immediately after development, at the start of operations, during maintenance, or during pre-sale inspections—it becomes easier to explain changes in land use. Chronological records are useful for land classification checks because there are cases where you need to confirm not only the current condition but also how the current use came about.

Step 3 Sort out the differences between land classification and current conditions

The third step is to reconcile the differences between the land category recorded in the registry and the actual conditions identified by the drone survey. At this stage, it is important not to assume that the mere existence of differences is a problem. Even if the registered land category and the on-site usage appear to differ, various circumstances may lie behind it, such as past procedures, the history of land development, changes in land use, or the allocation of use among individual parcels.

First, confirm the registered land category for each parcel and clarify how each parcel is actually being used. Check whether power generation equipment is installed, whether it is used as an access or management road, whether drainage facilities or slopes remain, or whether it is being managed as unused land. Overlaying lot numbers and parcel boundary information onto the results of drone surveys makes this clarification easier.

For example, even if solar panels are installed on the majority of a parcel, a portion of it may retain natural terrain. On another parcel, there may be no generation equipment, yet it may be used for plant operations as maintenance roads, fences, or drainage facilities. Also, land that appears to be on the perimeter of the plant may in fact be adjacent land rather than part of the plant site. If you proceed with land classification checks without organizing these differences, the explanatory materials will become ambiguous.

When assessing the current situation, it is important not to judge solely on whether equipment is present. In solar power plants, land without panels may still form part of the plant as maintenance access routes, slopes, drainage facilities, buffer zones, or weed-control management areas. When confirming land classification, it is necessary to record for what purposes the land is managed and how it is being used.

Also, areas where there is a large discrepancy between the actual condition and the land classification may require additional verification. The items that need to be checked vary by case, such as whether procedures related to farmland are necessary, permits and approvals for development or land reclamation, the need to register a change of land category, the status of boundary confirmation, and the scope of land under the contract. The results of drone surveying can serve as an entry point for such additional checks. By visually indicating which locations have differences, it becomes easier to explain the situation when consulting experts or relevant authorities.

What should be avoided in this situation is decisively asserting "this land's classification is such-and-such" based solely on drone imagery. Land classification is information related to registration and administrative procedures, and site photographs are only one of the materials for judgment. In practical documents, it is safer to separate observable facts and judgments, for example by stating "It can be confirmed that power generation equipment appears to be installed on site," "Conditions indicating use as a management road are observed," or "Some areas remain undeveloped or in a grassy state."

When organizing results from drone surveying, it is more practical for field work to classify existing conditions by area and explicitly indicate locations that require verification. For example, organize into categories such as power generation equipment area, pathway area, drainage area, slope area, unused area, and areas requiring confirmation with adjacent properties. The names can be adjusted to suit the project, but it is important to use expressions that all stakeholders will interpret in the same way.

Furthermore, when confirming land classification, adding a timeline to the description of the current condition makes it easier to understand. The site is currently used as a solar power plant, but past records may list it as being used for different purposes. If you can compare pre-development documents, documents from the start of operations, and current drone survey results, it becomes easier to explain changes in land use. When selling or transferring a power plant, organizing this history reduces the burden of later verification.

Step 4: Summarize into materials that can be shared with stakeholders

The fourth step is to compile the information organized for land classification confirmation into materials that can be shared with stakeholders. Even if drone surveys capture the current conditions, their practical value is not fully realized if the results remain understood only by the responsible personnel. It is important to present the information so that stakeholders—such as the power plant owner, management company, design personnel, construction company, real estate staff, legal personnel, financial institutions, and experts—can all view and verify the same information.

The basics of documentation are to organize registration information, parcel-specific extents, land categories, current-condition photographs, drone survey results, and items to be confirmed into a single sequence. First, indicate the overall location and extent of the site; next, show the land category for each parcel; and on that basis present the current conditions as captured by the drone survey. Finally, summarize locations where there may be discrepancies between the land category and the current conditions, and locations that require additional verification.

When doing so, it is effective to add clear annotations to drawings and images. Make explicit the items you want to confirm, such as the power generation equipment area, maintenance roads, drainage facilities, slopes, fences, and areas near boundaries with adjacent properties. Simply pasting aerial images can cause different viewers to focus on different places. In materials for land-use verification, a layout that makes it immediately clear what you want confirmed is important.

Also, in the materials, avoid definitive expressions and separate verified facts from matters that should be checked going forward. For example, the following organization can be considered: "The land category recorded in the registry is confirmed in the materials as follows," "On site, power generation equipment is installed in this area," "This section appears in the drone images to be used as a maintenance road," and "Whether a land category change or related procedures are required should be confirmed with a specialist."

In land-use confirmation for photovoltaic power plants, the information stakeholders want to see differs depending on their fields of expertise. Maintenance personnel may place importance on on-site accessibility and mowing boundaries. Real estate staff focus on land classification, area, and usage status per parcel. Legal personnel verify consistency with registration information, contract scope, and rights relationships. Design staff check the relationship between the development area, drainage plans, and equipment layout. The results of drone surveys can be used as a common document that connects these perspectives.

When preparing documentation, it is important to clearly state the date of the on-site inspection and the date the photographs were taken. The condition of land changes over time. Vegetation growth, additional earthworks, removal or installation of equipment, repairs to drainage channels, relocation of fences, and other changes can cause past images to differ from the current condition. If the date of photography is clearly indicated, you can later verify which point in time the document reflects.

Furthermore, it is convenient to prepare land classification check documents in a form that can be updated as management records for the power plant, rather than creating them once and leaving them as-is. At solar power plants, the same on-site information is often used for different purposes—pre-sale surveys, routine inspections, expansion planning, post-disaster checks, mowing plans, etc. By using the land classification check as an opportunity to organize the plant’s land information, it can then be utilized for subsequent management tasks.

Situations in Which Land-Use Classification Checks Are Important for Solar Power Plants

Situations in which confirming land classification for a solar power plant is important are not limited to the planning stage. Management after commissioning, buying and selling, inheritance and succession, financing, expansion, equipment upgrades, disaster response, and other timings all require verification of land information. Land classification is one of the basic pieces of land information, and understanding it together with the current site conditions makes it easier to carry out subsequent surveys and explanations.

When considering the construction of a new power plant or the expansion of an existing one, confirming the land's registered category and current status is an important element of initial investigations. By identifying early on what land category the site is registered as, how it is actually being used on the ground, and whether confirmation regarding site development or change of use is necessary, it becomes easier to determine whether plans need to be revised or additional surveys are required. Conducting drone surveys makes it easier to grasp the overall topography and land use of candidate sites and serves as a bridge between desk-based research and on-site surveys.

Even when buying and selling an existing solar power plant, confirming the land classification is important. Buyers need to check not only the power generation equipment but also land rights, each parcel’s land classification, current use, and conditions near the boundaries. Sellers, too, can streamline the verification process by organizing and presenting documents. If current-condition data from drone surveying is available, it is easier to share the overall condition of the plant and reduce discrepancies in understanding before and after on-site inspections.

Confirmation of land-use categories is also relevant in maintenance and management. For example, mowing areas, management responsibilities inside and outside fences, maintenance of drainage facilities, inspection of slopes, and checking boundaries with adjacent properties are closely related to the land’s extent and its usage. You do not check the land-use category itself every time, but if parcel-specific land information and current conditions are not organized, it becomes easy for decisions about the management scope to become ambiguous.

Drone surveying is also effective for post-disaster inspections. When heavy rain, typhoons, sediment outflow, slope failures, drainage problems, etc. occur, it is necessary to confirm which land parcels are affected, whether the damage is within the power plant site or on adjacent land, and whether it lies within the management area. Combining land-use information with current-condition data makes it easier to explain the extent of the damage and to consider restoration plans.

Furthermore, at power plants that have been in operation for a long time, construction records may have been lost or dispersed, and changes in personnel can make it difficult to grasp land information. Even when the operational status of the generation equipment is managed, there are cases where parcel composition, land classification, the extent of earthworks, and the current condition of the site perimeter are not sufficiently organized. In such cases, using drone surveying to re-document the current conditions can also help update management records.

It is more effective to organize land classification verification during normal conditions than to rush to do it after a problem occurs. If you have drone survey results from normal times, you can compare later changes or damage conditions. In particular, solar power plants are outdoor facilities installed for long periods, and land conditions change over time. By regularly keeping records of current conditions, you can not only verify land classification but also improve the overall accuracy of operation and maintenance.

How to Proceed with Inspections Without Relying Solely on Drone Surveys

Drone surveying is a useful tool for confirming land classification, but it should not be relied on alone to complete the verification. For confirming the land classification of solar power plants, it is important to combine registration information, plans, past procedural documents, on-site inspections, interviews with stakeholders, and expert judgment as needed. Drone surveying serves to clearly show the current conditions within that process.

First, checking the registration information is essential. Because the land category is information on the registry, it cannot be determined solely by the appearance on site. Confirm the parcel number, land category, and land area from the registration information, and determine the positional relationships of the parcels using cadastral maps and land survey diagrams. By overlaying the drone survey results, it becomes easier to compare the information on the documents with the actual on-site conditions.

Next, check past procedural documents. For solar power plants, there may be documents related to site formation, farmland conversion, development, drainage, road access, equipment installation, and so on. These documents provide clues for understanding the process that led to the current land use. By using drone survey results to grasp current conditions and cross-referencing them with past documents, it becomes easier to identify which parts have been changed or show discrepancies.

On-site verification is also important. While drone surveying allows a broad overview from the air, boundary markers, small structures, ground surface conditions, signs, traffic conditions, and details of drainage ditches can sometimes be more reliably checked on the ground. By extracting areas of concern from aerial images and focusing on those during on-site inspections, the efficiency of the survey can be improved.

Also, when decisions involving land classification, boundaries, registration, or permits and approvals are required, it is advisable to consult a professional. If you include the results of drone surveying when consulting, it will be easier to explain the on-site conditions. Showing aerial images and area maps, rather than explaining with words alone, makes it easier to share the points at issue.

What practitioners should be careful about is not to over-rely on the results of drone surveys. Even if the images are clear, they only show the conditions at the time of capture. The legal treatment of land classifications and the necessary procedures require document review and professional judgment. Drone surveys are best used as current-condition materials to support decision-making.

On the other hand, if you proceed with verification using only documents without drone surveying, you may overlook the actual conditions on site. In particular, solar power plants have equipment dispersed across wide sites, making it difficult to grasp the whole from the ground. Even if no problems are apparent on paper, on site you may find points that need to be checked, such as the locations of pathways, the use of areas outside fences, the shape of slopes, and points of contact with adjacent land.

Therefore, in land classification checks it is important to regard document review and drone surveying not as opposing methods but as complementary to each other. Confirm the land category and parcel from documents, use drone surveying to grasp the existing conditions, verify necessary locations on site, and consult on parts that require professional judgment. Establishing this workflow makes it easier to reduce omissions in verification.

Summary: Start Land Category Confirmation by Visualizing the Current Conditions

When confirming the land classification of a solar power plant, it is important to separate registry information from the actual on-site land use. Land classification is information related to registration and cannot be determined by drone surveying alone. However, by utilizing drone surveying, you can visually grasp the plant’s overall land use, equipment layout, access and maintenance roads, slopes, drainage facilities, and relationships with adjacent land, making it easier to organize the on-site conditions needed for confirming the land classification.

In practice, you first reconcile the registration information with the on-site boundaries, then record current land use with drone surveying. Next, you organize the differences between the official land classification and the actual conditions, and compile them into materials that can be shared with stakeholders. By following these four steps, the points that need to be checked become clear, making it easier to reduce misunderstandings between staff and rework in later stages.

In particular, at solar power plants, sites that span multiple parcels, sloping terrain, developed areas, unused land, drainage facilities, and fence perimeter areas often coexist, making it difficult to grasp the overall picture from ground-level inspection alone. By utilizing aerial images and point cloud data from drone surveys, you can capture how the land is used across the site and preserve it as documentation.

However, drone surveying is not a cure-all. Only when used in combination with registration information, drawings, past procedural documents, on-site verification, and expert judgment does it lead to a confirmation of land category that can withstand practical use. Separating and organizing the facts visible in images from judgments related to registration and procedures is the basic principle of preparing safe documentation.

When you want to efficiently proceed with land classification confirmation for a solar power plant, it is effective to start by visualizing the current conditions. Organizing land information, accurately recording on-site conditions, and preparing materials so that stakeholders can make decisions while viewing the same documents creates foundational resources useful for the plant’s planning, management, sale, and updates. As a practical means to carry out such current-condition assessments, combining the results of drone surveys with registry documents and on-site inspection findings makes it easier to advance the full range of tasks from land verification to preparing management materials.