4.3.2. Terrestrial or Close-range photographs

Terrestrial or close-range photographs are taken when the camera, either hand-held or tripod mounted, is located on or near the ground. For a detailed mapping of the feature/object, the camera is set up close to the object and photographs are taken.

Terrestrial photographs are a type of imaging used in photogrammetry where a camera is positioned at ground level, often either held by hand or placed on a tripod. This technique is especially useful for capturing detailed images of nearby features or objects. The close proximity of the camera allows for more detailed images, which is essential for accurate mapping and analysis.

Think of taking a close-up photograph of a flower in your garden. The closer you get to the flower, the more details you can capture, such as the veins in the petals or the texture of the leaves. Similarly, terrestrial photographs allow us to get a 'close-up' view of objects on the ground, providing detailed information for mapping.

The output may be photographs or non-topographic products, like 3D models, measurements, or point clouds.

When terrestrial photographs are captured, the results can vary widely. The simplest output is just the photographs themselves. However, more advanced techniques can be used to create non-topographic products, which include three-dimensional models of objects, precise measurements, or point clouds that represent the shape of the photographed objects in 3D space.

Imagine an architect who takes photographs of a building for a renovation project. Instead of just having flat images, they could use those images to create a detailed 3D model of the building. This model could then be manipulated to visualize how changes would look before any work is done, much like turning a cube in a video game to view it from different angles.

Close-range photogrammetry has been applied for precise deformation measurements in industrial and engineering applications. There are many uses of terrestrial or close-range photogrammetry, such as 3D modeling of objects, monitoring of dam structures, buildings, structures, towers, or movie sets, architectural restoration, preserving the cultural heritage, location of monuments, medical imaging for forensic sciences and reconstructive surgery, facial reconstruction studies, structural stability studies of bridges and hydro-electric dams, earth-works, stock-piles, automobile industry, shipping industry, antenna calibration, study of traffic accidents and crime scenes by police departments, etc.

Close-range photogrammetry is highly versatile with numerous applications across various fields. Industries use it for monitoring structural integrity, where deformation measurements can highlight potential issues in engineering structures like dams or bridges. In film and entertainment, it can create intricate 3D models of set designs, while medical fields may utilize it for detailed analysis of human features, aiding in tasks like reconstructive surgery.

Consider a movie production team that needs to create a realistic 3D set for a sci-fi film. They use terrestrial photogrammetry to capture detailed images of their physical set, creating a 3D model that allows them to visualize and adjust the scenery digitally before filming. Similarly, engineers might track changes in the shape of a bridge over time by taking regular close-range photographs to ensure continued safety and structural integrity.

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