4.2 Aerial Photogrammetry (Drone mapping)
Taking aerial photos is one of the most common approaches to mapping out an area. In this process, a camera is mounted on an aircraft and pointed toward the ground with a vertical or near-vertical axis. As the plane follows its flight path, the camera takes multiple overlapping photos, which are then processed in something called a stereo plotter.
The stereo plotter is an instrument that helps determine elevations by comparing two different photos and conducting the necessary calculations. With the help of photogrammetry software, we can process this information and create digital models out of it.
These images are taken from a fixed position on the ground with a camera’s axis parallel to the Earth. Data about the camera’s position, such as its coordinates, are collected at the time the photo is taken. The instruments used for terrestrial photography are often theodolites, though regular cameras are sometimes used as well. Terrestrial photogrammetry for surveying typically requires fewer resources and skilled technicians to accomplish, but it may take longer to cover a large portion of land.
Uses of photogrammetry
The ways that photogrammetry comes to life can vary widely by collection method, data gathered, industry use and compatible technologies.
Some of the products that come from the process include orthomosaics, digital surface models and digital terrain models. An orthomosaic is essentially a birds-eye view of a terrain that adjusts for distortion and can span wide landscapes. Digital surface models and digital terrain models represent surface levels and elevation. Surface models include
buildings and trees, while the terrain model gets rid of all of these features, showing the height of the bare earth.
The most common use for photogrammetry is creating maps out of aerial photos. It is cost-effective and accurate, allowing planning entities like architects, local governments and construction workers to make clear, informed decisions about their projects without spending months scouring the landscape. It is also very detailed and can provide an exceptional level of information about an area.
Photogrammetry makes its mark in an array of industries, from medical research to film and entertainment. Here are some of the places you can find it:
We’ve already discussed the applications of photogrammetry in civil surveying, the results of which are used by many entities, including construction crews, governments, building planners and architects. All of the data gathered from photogrammetry inform them about everything from necessary safety measures to potential project results.
In the world of engineering, drone photography helps to evaluate sites for construction, as well as create perspective images and 3D renderings. Engineers can produce images of project results or previews, as well as analyze their current progress.
In the digital age, where 80% to 81% of millennials find their homes on mobile devices, creating attractive, accurate listings can significantly improve the buying experience and their understanding of the purchase. Viewers can see the home from all angles and get a clear idea of what they’re looking at.
Photogrammetry also plays a role in data gathering for military programs. Accurate geo- locational models with low processing times are necessary for understanding a landscape. Aerial imagery and photogrammetric technology can work together to create accurate 3D maps quickly without any human input.
Film and entertainment
Photogrammetry can play a big role in set design and world-building for a variety of films and video games. 3D modeling can bring unique objects to fruition in a virtual world, like cityscapes for action sequences and accurate historical elements, such as statues and buildings. One popular franchise that uses photogrammetry is the “Battlefield” games, which have an art style that works well with these 3D renderings and recreations.
In addition to world-building, photogrammetry can also assist with designing special effects and real sets.
Photogrammetry also plays a part in crime investigation. It can help to document and measure precise data about a crime scene and determine what was physically possible. There are also many photogrammetric experts that can assist in the courtroom.
Construction and mining
Project engineers and contractors can use accurate 3D models to monitor and plan their worksites. The information from a photogrammetric model can help create a smart worksite with sensors and safety features that improve the environment. These models work in tandem with connected vehicles.
Analyzing athlete movements can help coaches and researchers understand more about their activities. They can develop virtual training systems and learn about the physical effort that players expend by tracking their body movements. Topographical maps also come in handy for outdoor athletes, like hikers, mountain climbers, skiers and snowboarders. Mapping remote areas is often easier with the help of photogrammetric technology.
Agriculture and forestry
In agriculture, aerial photos can offer insights into soil quality, irrigation scheduling, nutrition and pests. Farmers can adjust their planting schedules or adjust irrigation and fertilizers with this information. They can also use photogrammetry when assessing growth and crop damage after storms or floods.
Researching and managing forests becomes significantly easier with the help of photogrammetry. It can produce models to analyze various aspects of a forest, like timber volume and height, to better understand the development of a forest