Orthoimage generation made easy in the cloud – No specialist knowledge or high-end PC required, high-accuracy results in a short time

Table of contents

• What is an orthoimage?

• Traditional orthoimage creation and its challenges

• Orthoimage generation evolving in the cloud

• Benefits of using the cloud

• How high-accuracy results are achieved quickly

• Why anyone can use it without specialist knowledge

• Fields where orthoimage use is expanding

• Summary

• Frequently asked questions

What is an orthoimage?

An orthoimage is an image created by correcting the “distortions” of terrain and buildings that appear in photos taken from the air or elevated positions, converting them into a view as if looking straight down. The word “ortho” comes from Greek, meaning “correct” or “straight,” and, as the name implies, orthoimages lack the tilt and perspective distortion seen in ordinary oblique photographs. Think of the aerial imagery layer in online maps: building facades do not appear slanted and only roofs are visible from above because after shooting a process called orthorectification (ortho correction) is applied to transform all objects into their planimetric shapes. Orthoimages, also called orthophotos, are represented at a uniform scale like maps, which means distances and areas can be measured accurately.

Generally, an orthoimage is not produced from a single photograph; to cover a wide area multiple aerial images are stitched together. Dozens of photos taken by drones or aircraft are seamlessly connected through mosaic processing to create a single large ortho mosaic image. At this stage, lens distortions and misalignments caused by terrain relief in each photo are corrected by calculation to produce a precise image that looks like a map viewed from above. Orthoimages have traditionally been used professionally in aerial surveying and geospatial fields, but the recent spread of small drones has made it possible to obtain high-resolution orthoimages by more accessible means.

Traditional orthoimage creation and challenges

Before looking at new cloud-based methods for orthoimage creation, let’s review the traditional approach and its challenges. To generate an orthoimage from photos taken by drones or aircraft, the common method until now has been to use specialized photogrammetry software (photogrammetry tools). A large set of image data is imported into that software, and processes such as feature-point matching and 3D reconstruction are executed on a local PC. While obtaining high-precision orthoimages is possible, there have been several major hurdles.

• High-spec PCs and expensive software required: Processing to analyze aerial photos and generate point clouds or orthoimages requires a high-spec PC with strong CPU/GPU power and large memory. The photogrammetry software used is often specialized and costly, making adoption difficult for small-to-medium businesses and local governments.

• Long processing time and effort: Analyzing hundreds of photos can take considerable time; it was not uncommon for calculations to run overnight on a PC so that results were available the next day. There are many configuration settings during analysis, and achieving optimal results required trial and error by technicians with expertise in camera calibration and matching parameter adjustment.

• Data management burden: Generated orthoimages are very high resolution and file sizes can reach several GB. Preparing the environment to store and share such results was a challenge. Exchanging large datasets among stakeholders was not easy, and viewing often required GIS software or a specialized viewer.

• Additional manual work: Using the results sometimes required further editing. For example, creating cross-sections or adjusting overlays with other map data often involved manual processing. Such manual tasks not only increase workload but can also introduce errors.

Thus, traditional methods had many issues in terms of cost, time, and effort, and aerial photos taken could not always be fully utilized.

Orthoimage generation evolving in the cloud

What changed this situation was the emergence of services that complete orthoimage generation entirely in the cloud. By using a cloud service, users simply upload the photos taken on site to the web, and the server automatically performs orthoimage generation processing. Because high-performance cloud server resources can be utilized over the internet, it is possible to analyze large numbers of photos even without a high-spec PC on hand.

Let’s briefly look at how cloud-based orthoimage generation works. First, users access the cloud service via a web browser, create a project, and upload the photo data for the target area. On the cloud side, photogrammetric algorithms run to detect common feature points across multiple photos and calculate the positional relationships among images. This allows reconstruction of the three-dimensional structure of the shooting area, generating point clouds and digital terrain models. Based on that 3D information, each photo is corrected to a nadir view and stitched together, automatically producing a high-precision ortho mosaic image. All heavy computations are performed in the cloud, so the user’s PC load is minimal. The service can be operated from a notebook PC or tablet, and once upload is complete, the user simply waits for the results. When processing finishes, the generated orthoimage can be previewed in the browser or downloaded in the required format.

Benefits of using the cloud

Switching to the cloud resolves the constraints of traditional methods at once and offers many benefits to users. Here are the main advantages.

• No specialized hardware required: Since intensive analysis is performed on cloud servers, users do not need to prepare high-performance workstations or GPUs. Processing proceeds fine even with an ordinary notebook PC.

• Fast processing and time savings: The cloud can run image analysis with a large number of CPU cores and GPUs in parallel, dramatically improving processing speed. Orthoimage generation that used to take overnight can often be completed in several hours on the cloud. This shortens lead times from fieldwork to office reporting and speeds up overall operations.

• Low-cost scalability: Without having to purchase expensive surveying software or hardware in-house, cloud services allow resources to be used only when needed. This reduces initial investment and lets projects scale from small to large, offering excellent cost performance.

• Easy data sharing: Analysis results are stored in the cloud, making it simple to share outcomes online with stakeholders. There is no need to email huge files or exchange hard drives, and multiple people can simultaneously view orthoimages on a web platform.

• Automatic output of multiple deliverables: Some cloud services automatically generate not only orthoimages but also point cloud models, DSMs (digital surface models), cross-sections, and numerical map data in one stop. This reduces manual follow-up work and smooths the workflow to data utilization.

• Maintenance-free: Software version management and updates are handled by the service provider, so users always have access to the latest analysis technologies. Users are freed from complicated system maintenance and can focus on learning how to use the service.

How high-accuracy results are achieved quickly

There are technical reasons why cloud orthoimage generation enables “high-accuracy results in a short time.” Regarding reduced processing time, as noted earlier, the cloud’s powerful computing environment plays a major role. Even for sets of several hundred photos, advanced parallel processing enables analysis to be completed at speeds far faster than traditional methods. After uploading shooting data, the user only needs to wait and does not have to sit by a PC monitoring progress.

Regarding improved result accuracy, cloud services provide optimization and correction techniques. For example, they make skillful use of geotags and IMU data embedded in images to improve image alignment precision. Some services also allow input of ground control point (GCP) coordinate data or uploading positioning logs from RTK-equipped drones. Using these features, orthoimages can be aligned to a specific geodetic coordinate system, making it possible to obtain orthophotos with absolute coordinates and position accuracy on the order of several centimeters (cm-level accuracy, half-inch accuracy). Despite these advanced processes, they run fully automatically, so users can obtain high-precision results without needing to follow specialist procedures.

Why anyone can use it without specialist knowledge

Cloud-based services are designed so they can be used without specialist knowledge. The user interface is intuitive and easy to understand; following onscreen prompts to upload photos and enter basic items starts the processing. Complex parameter settings are pre-tuned by the system, so users do not need to adjust detailed analysis conditions one by one. Image processing that formerly required experienced photogrammetrists is black-boxed in cloud services, allowing good results without awareness of the internal advanced algorithms.

Moreover, domestically provided services often include comprehensive Japanese manuals and support, so first-time users can feel secure. If you get stuck, help centers and inquiry desks are available to consult, and specialist staff will guide you to resolution. The necessary knowledge is generally limited to basic drone shooting methods and basic file operations on a computer. By following cloud-based guides, anyone can complete the orthoimage generation workflow. This ease of use for non-surveying specialists is the greatest attraction of cloud services.

Fields where orthoimage use is expanding

Because cloud-based orthoimage generation makes high-precision aerial imagery easier to obtain, its applications are expanding rapidly. Below are representative fields and example uses.

• Civil engineering and construction: Orthoimages are used to grasp site conditions and for as-built management at construction sites. Because wide areas can be accurately viewed from above, they are useful for monitoring earthworks progress, calculating earth volumes, and recording construction locations. Overlaying orthoimages with CAD design data allows checking whether constructed shapes match the plan. With initiatives such as the Ministry of Land, Infrastructure, Transport and Tourism’s i-Construction, orthoimages are becoming indispensable for digital surveying in construction.

• Government and public sector: Local governments and administrative agencies are increasingly using orthoimages. For example, in farmland parcel surveys or river maintenance, periodic drone-captured orthoimages can be compared to understand changes over time. Public surveying that used to rely on manned aircraft with high cost and effort can now be performed at lower budgets and shorter timeframes with small drones and cloud processing. Some municipalities are using orthoimages as baseline data for cadastral surveys and urban planning.

• Disaster response and mitigation: Drone orthoimages are powerful for assessing disaster areas that are difficult for people to access. Capturing landslides or flood-damaged areas from the air and converting them to orthoimages via cloud processing enables rapid identification of affected extents and situation assessment. In disaster response, time is critical, and cloud-based image generation can allow sharing of the latest information with relevant agencies on the same day as shooting. Keeping a stock of high-precision orthoimages in peacetime also supports damage comparison and simulation when an event occurs.

• Agriculture and forestry: Orthoimages are being used for farm and forest management. Aerial imaging of entire fields with drones allows monitoring of crop growth and disease locations from above, enabling efficient agricultural planning. Measuring plot areas and understanding vegetation distribution on orthoimages reduces manual survey work. In forestry, orthoimages help identify harvest areas and locations of damaged trees across vast forests, contributing to improved resource management.

Beyond these, orthoimages are useful in archaeology for recording subtle ground undulations at sites, in cultural property protection, environmental monitoring, and infrastructure inspections. As cloud-based orthoimages become easy to obtain, new application scenes will continue to be developed.

Summary

Combining drone aerial photography with cloud processing has made orthoimage generation remarkably easy and accessible. Tasks that once relied on specialist contractors and expensive equipment can now yield high-precision results with just a single PC. Orthoimages, which allow rapid acquisition of up-to-date, wide-area data, strongly support on-site DX (digital transformation). Cloud-based orthoimage generation is becoming the new standard for surveying and investigation, delivering overwhelming efficiency and labor savings compared to traditional methods.

In particular, simple surveying with LRTK allows automatic generation of point cloud data with absolute coordinates simply by uploading photos taken by a drone to the cloud, enabling orthoimages and cross-sections to be obtained together. With ease of use for non-specialists and the attentive support typical of domestic vendors, even first-time users can adopt it with confidence. Why not leverage cutting-edge technology to further accelerate surveying DX in the field?

Frequently asked questions

Q: What’s the difference between an orthoimage and a regular photo? A: An orthoimage is a photo corrected to appear as viewed from directly above, and the whole image is at a uniform scale—this is the main difference from regular photos. Oblique photos taken from an angle show building sides and perspective distortions in dimensions, but in an orthoimage all objects are transformed to their planimetric shapes, allowing distances and areas to be measured accurately as on a map.

Q: Can a beginner create orthoimages if they have a drone? A: Yes. If you know basic drone operation and photographic procedures, a beginner can create orthoimages. Nowadays, automatic flight apps make it easy to set shooting routes, and cloud services for uploading and analyzing photos have appeared. Start with a small area for practice, and as you gain experience gradually expand the coverage to acquire skills smoothly.

Q: Do I need expensive software or a high-performance PC to create orthoimages? A: Not necessarily. Orthoimage generation uses specialized photogrammetry software, but there are open-source options and cloud services available for a usage fee. Using cloud services allows processing large numbers of photos without a high-performance PC, so you can start creating orthoimages without large upfront investment. Commercial drones for aerial photography are generally sufficient, so try with readily available equipment first.

Q: How accurate are orthoimages created by drones? A: When processed properly, drone-derived orthoimages can represent terrain with accuracy on the order of several centimeters. However, absolute positional accuracy depends on the GPS and correction methods used. Relying solely on the built-in GPS of consumer drones can result in horizontal offsets on the order of several meters, but using ground control points (GCPs) or RTK-enabled drones can improve accuracy to within a few centimeters. The advantage of drone orthoimages—rapid coverage of wide areas—remains significant even considering such accuracy requirements.

Q: In what forms can orthoimages be used? A: Orthoimages are a type of digital map data and can be used in many ways. They can be loaded into GIS software as base maps, overlaid on CAD drawings for comparison with as-built conditions, and used for distance and area measurements in site surveys, farm management, and post-disaster damage assessments. They can also be printed for inclusion in reports or overlaid on web map services for public release. Accurate, up-to-date orthoimages are widely used as objective material for decision-making.

Q: How many photos do I need to take to create an orthoimage? A: The number of photos required depends on the area to be covered and flight altitude. For example, with a standard camera on a drone shooting from an altitude of 100 m (328.1 ft), a single photo can capture an area on the order of several thousand square meters. Creating an orthoimage for several hectares typically requires dozens to hundreds of photos with sufficient overlap in front/back and side directions. Drone battery limits mean large areas are often flown in multiple missions. While more photos increase processing time, cloud services can efficiently analyze large datasets.