Aerial survey methods involving drones provide an incredible advantage over traditional survey methods: they furnish a clear, bird’s eye view of the survey site in a fraction of the time. An eye in the sky allows professional surveyors to use photogrammetry to create numerous types of actionable maps that have applications across a wide range of industries. One aerial survey type is the orthomosaic map.
What is an Orthomosaic Map?
Orthomosaic maps are detailed, high-resolution images of the terrain below. As the drone flies above its target, it takes numerous pictures of the landscape directly below it from a vertical nadir angle. Once the flyover is complete, a surveyor can use various mapping software to stitch together the images into one giant mosaic of the terrain in question. These images are photo-realistic, meaning they include information about the landmarks, relief, and distance between objects in great detail. Orthomosaic images give the viewer a clear picture of the shape and quality of the landscape below.
Because of the level of detail inherent to orthomosaic images, a lot of different kinds of advanced mapping functions are available as a result. Orthomosaics serve as the basis for features such as cloud point models which allow surveyors to insert 3D images into their finished product. However, there is one major drawback when compiling an orthomosaic map: distortion.
What is Orthorectification?
There is one severe limitation to the photography a drone generates while compiling an orthomosaic image. Images obtained as part of the mosaic are subject to distortion. There are three common factors that can cause this type of visual inaccuracy:
- The landscape’s actual topography
- Distortion from the camera’s lens
- The camera’s tilt or angle
With an orthographic map, the finished product is known for its ability to show the actual topography of your survey area, as well as being distortion free. In order to achieve that distortion-free quality, an orthomosaic map must be orthorectified as it’s being stitched together. That means piecing together the mosaic of images in such a way that it eliminates the various types of camera and topographical distortions to create a finished map with a uniform scale and perspective. This can be accomplished using various topographical mapping applications.
What are the applications of an orthomosaic map?
The process of creating an orthomosaic map is fairly complex, but the results are worth the effort. A detailed, topographically-accurate map can be produced very quickly in comparison to traditional survey methods. As a result, orthomosaic maps can be put to good use across a wide variety of industries including:
- Emergency response
- Farming
- Construction
- Real estate
- Insurance
- Telecommunications
First responders can use orthomosaic images to help assess the damage from natural disasters. For police and EMTs, orthomosaics serve a much more proactive approach in helping them to monitor an ongoing crisis. The detailed, bird’s eye view available can help responders, as well as insurance professionals, piece together the true extent of the damage.
Orthomosaics are useful in the construction industry because they can provide continuous updates for ongoing projects, featuring the totality of the worksite, including the structure’s progress and the surrounding environmental impact. Survey professionals can build 3D structures to insert into their map using cloud points, creating a virtual tour for key stakeholders in the project.
The real estate industry uses orthomosaic mapping in a similar capacity, giving investors a comprehensive view of the property, creating 3D models of the building, and helping to proactively identify elements that need repair. The agricultural industry uses orthomosaics to track crops yields from year to year and help mitigate the spread of pests and other famine-causing agents.
Orthomosaic mapping provides a highly-detailed, topographically-accurate view of the landscape below. The applications are translatable to so many different industries. To learn more about how orthomosaic mapping using UAV technology can work for your business, please contact Mile High Drones today.