Aerial photography
Aerial photography is a technique that captures images of the Earth's surface from elevated platforms such as balloons, airplanes, and satellites. Originating in the nineteenth century, it provides a unique perspective that enhances our understanding of land use, ecological changes, and resource distribution. The first recorded aerial photograph was taken in 1858, and the technology has evolved significantly since then, with the advent of satellite imagery in the late 1950s. Aerial photography plays a crucial role in various fields, including agriculture, urban planning, and environmental monitoring.
By employing photogrammetry, analysts can extract quantitative information from aerial images, enabling them to assess spatial relationships and terrain features accurately. This technique allows for the identification of vegetation types, soil conditions, and even geological formations, making aerial photography an essential tool for scientists and resource managers. Furthermore, the ability to capture wavelengths of radiation beyond human vision adds depth to the analysis, revealing information about temperature and health of plant canopies. As global resource demands increase, aerial photography remains vital for sustainable management and planning efforts across diverse landscapes and ecosystems.
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Aerial photography
Aerial photography, which dates to the nineteenth century, has enabled scientists to quantify and predict changes in land use, soil erosion, agricultural development, water resources, habitat, vegetation distribution, animal and human populations, and ecosystems. Aerial photography also is used to construct thematic maps that show the distribution of a variety of global resources.
Definition
Aerial photography is a form of that relies on film or digital capture to acquire information about Earth’s surface from elevated platforms. These platforms include balloons, airplanes, and satellites. The primary advantage of aerial photography over ground-based observations is the elevated vantage point, which can provide images covering vast expanses of Earth’s surface.
Overview
The invention of photography was announced in 1839 at the joint meeting of the Academies of Sciences and Fine Arts in Paris, France. Nineteen years later, in 1858, Gaspard-Nadar Félix Tournachon made the first aerial photograph from a tethered balloon over Val de Bièvre, France. The oldest extant aerial photograph dates to 1860, when James Wallace Black photographed Boston, Massachusetts, from a balloon tethered above Boston Common. The first aerial photograph made from an airplane was in 1908; the first aerial photograph made from a satellite was in 1959. In the twenty-first century, aerial photography is a vital tool for documenting and managing Earth’s resources.
In order to obtain quantitative information about the Earth’s resources from an aerial photograph, methods must be applied to the photograph that allow for reliable estimates of spatial relationships. Obtaining such relationships falls under the broad field of photogrammetry. By applying photogrammetric methods, analysts can relate distances on the photograph to distances on the ground. Object heights and terrain elevations can be obtained by comparing photographs made from two different vantage points, each with a different line of sight. This method is based on the principle of parallax, wherein the apparent change in relative position of stationary objects is compared between the photographs. Additional information can be gleaned from aerial photographs by examining tonal changes and shadow distributions within the photograph. Tonal changes can provide information on texture, which can be used to distinguish between vegetation type, soil type, and other surface features. Because the shapes of shadows change with the time of day and are unique to particular objects, such as bridges, trees, and buildings, the shadows can be used to aid in the identification of the objects. Because film can record wavelengths of radiation that are invisible to the eye, such as thermal infrared radiation, features such as plant canopy temperature can be measured and displayed on an aerial photograph.
Aerial photography has many applications, including geologic and soil mapping, agricultural crop management, forest monitoring and management, rangeland management, water pollution detection, water resource management, and urban and regional planning. In geologic mapping, for example, aerial photography can be used to identify faults and fractures in Earth’s surface as well as and soil types. By comparing these features over time, scientists can make inferences about the forcing agents, such as wind and water, that have shaped the land. As the world population grows and demand for global resources increases, aerial photography will continue to be an important tool for guiding global resource management.
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