What defines an orthophoto?

An orthophoto is defined as an aerial photograph that has been geometrically corrected to produce a uniform scale. This means that the distances measured in the orthophoto are accurate and comparable to ground distances, similar to that of a map. This correction accounts for distortions caused by mountain terrain, lens curvature, and the angle from which the photograph was taken, ensuring that measurements can be reliably used in geographic analysis.

In contrast, aerial photos with varying scales may possess distortion due to elevation changes in the landscape, making them unsuitable for precise measurements. Oblique angle aerial photos, while useful for certain visual perspectives, do not provide the orthorectification necessary for a uniform scale. Similarly, satellite photographs may offer valuable data, but they are not classified as orthophotos unless they undergo similar geometric correction procedures to ensure uniformity in scale.