Orthophotography

Part of speech: noun

Definitions

  1. The science and practice of creating aerial photographs geometrically corrected to have a uniform scale, useful for mapping and spatial analysis; the technique of producing orthorectified images by removing distortions from terrain and camera tilt; images generated through a process that combines aerial imagery with precise measurements to produce accurate, map-like photographs
  2. A method involving the correction of aerial images to produce scale-consistent photographs devoid of perspective distortions for use in cartography; the procedure of transforming raw aerial photos into geometrically precise images reflecting true ground positions; aerial imagery processed through correction algorithms to enable accurate measurement and mapping applications
  3. The discipline that entails converting aerial photographs into true scale images through geometric correction, enabling their use in surveying and geographic information systems; the creation of orthorectified images by adjusting for topographic relief and sensor angles; precisely adjusted aerial pictures used as reliable, distortion-free representations of the earth’s surface for analysis and mapping purposes

Etymology: Orthophotography is a modern technical coinage, built in English from two Greek roots. "Ortho" comes from Greek "orthos", meaning "straight" or "correct", and "photography" combines "phōs" (light) with "graphē" (writing or drawing), so the word literally means something like "correctly drawn by light." The earlier half is the ancient part; the compound itself was assembled much later, as a precise name for a specialised process. The point of the prefix is the distinction it draws. An ordinary aerial photograph is distorted: the camera's tilt, the curvature of the lens, and the rise and fall of hills and buildings all shift features away from their true positions on the ground. Orthophotography removes those distortions so that every point on the image sits at its correct map location and at a uniform scale, which is why surveyors can measure distances directly from it, much as they would from a map.

Synonyms: aerial mapping, orthophoto production