Drone photogrammetry is growing in popularity as more industries discover the value that 3D orthomosaic maps create for their internal teams and their customers. Despite this emerging visibility, many people are still unsure about what goes into an orthomosaic map and how to generate one.
In this post, we’ll explain how to use drone photogrammetry to create orthomosaic maps and address some updated best practices to help you get the results you want.
Orthomosaic maps offer a photorealistic representation of an area that can produce surveyor-grade measurements of topography, infrastructure, and buildings.
Each orthomosaic map is made up of dozens of orthoimages (also called orthophotos). An orthoimage is an extraordinarily detailed aerial photograph that is pinned to a geographic position to create continuity and uniformity when sequenced by mapping software. A dataset made up of numerous orthoimages is collected with detailed documentation on their geographic position and any external factors that could impact the collected data.
To produce a uniform scale, orthoimages are normalized for factors including altitude, lens distortion, camera tilt, and environmental conditions such as humidity. Once they’re corrected, the images can be stitched together with advanced mapping software to produce a 2D or 3D orthomosaic map.
More than just a tech-savvy atlas, cutting-edge orthomosaic maps can be used to document changes in local vegetation or landscape over time, which can be helpful in a number of use cases, including environmental monitoring, emergency response, and much more.
They are detailed enough to measure distance, height, and depth on land masses and human-made structures, which allows users to instantly source accurate on-the-ground conditions and information from anywhere in the world.
This emerging technology is especially valuable for industries that monitor, secure, and maintain infrastructure in distant, often very isolated rural locations—telecommunications, utilities, and oil/gas, to name a few.
A normal aerial photo that has not been orthorectified has a perspective view. This means that you can see objects from an angle—not directly from above. With every image collected, the perspective changes, which makes it impossible to stitch the photos together to get a cohesive view.
An orthophoto has been corrected to account for the camera angle, so the view is directly from above, no matter where an object is located in the image. This consistent and more accurate view allows orthophotos to be combined to create a larger map.
Applications for orthomosaic maps are limited only to the imagination. Several industries have readily adopted drone mapping technology to create orthomosaic maps.
Perhaps the most natural fit for drone mapping is surveying, the technique for determining the 2D or 3D locations of points and the distances and angles between them. Surveyors can use aerial orthomosaic maps to:
Farmers and agriculture companies have adopted drones as another tool in the toolbox for reducing their environmental impact, optimizing production, and more:
Federal, state, and local public safety officials use drone photogrammetry in both proactive and reactive ways:
Traditionally, aerial photography was performed by manned aircraft or distant satellites, each of which has shortcomings. For example, airplanes and helicopters are highly susceptible to environmental conditions and human error, while satellite technology is prohibitively expensive for most firms.
UAV technology allows users to carefully map out flight plans and capture high-resolution images with minimal distortion. The ease of use and extraordinary mobility of unmanned flight makes high-quality data collection simple, safe, and accessible. Drones have also lowered the bar of entry with regards to cost, which is driving an explosion in research and innovative new use cases.
Producing high-quality orthomosaic maps involves detailed flight planning and data organization. When developing a flight path for a project, you need to prioritize three key factors:
Thanks to advanced mobility and hovering, creating a tightly managed flight plan using a UAV drone makes curating high-quality images with consistency and proper alignment easier than ever.
It’s not just the images themselves that make an orthomosaic map work. Metadata collected alongside each image allows processing software to build an accurate schematic from dozens or even hundreds of unique images.
In this context, metadata is a collection of data-encoded notes that are pinned to images to organize them along a flight path. It ties the image to a GIS location and provides context into other factors that may influence data normalization, such as time/date, focal length, resolution settings, and weather conditions.
Metadata should also document who created a data set and under what conditions, both factors that may influence whether data is appropriate for an orthomosaic map. Without accurate metadata, any aerial photographs collected or maps created aren’t reliable.
Going from a catalog of digital images to a fully dynamic 3D experience requires advanced digital processing. The tools you select will impact the quality of the map created, and unfortunately not all photogrammetry software is up to the challenge.
When shopping for a photogrammetry processing software, here’s what to look for:
Mapware is powerful photogrammetry software designed by experts in the field of drone-mounted photogrammetry. It’s designed to process your images and data faster than ever, all from an easy-to-use platform.
As more innovative use cases are developed, more industries are discovering the full potential of drone photogrammetry. As drone technology advances and data and imaging software improves, the horizons of what this powerful technology can do will only grow.
Ready to put Mapware to work for you? Start a free trial today!