ortophoto

An ortophoto is a photograph that has been geometrically corrected to remove lens distortion and perspective effects. Unlike a standard aerial photograph, an ortophoto has a uniform scale throughout, meaning measurements can be taken directly from it with accuracy. This correction is achieved by using a digital elevation model (DEM) of the terrain. The process essentially reprojects the aerial photograph onto a flat plane, accounting for variations in elevation.

The primary purpose of an ortophoto is to provide a spatially accurate and georeferenced image that can be used as a map or as a base layer in geographic information systems (GIS). They are valuable tools for various applications, including land management, urban planning, environmental monitoring, and cadastral surveys. Because they represent the Earth's surface without geometric distortion, they are often referred to as "photomaps." The creation of ortophotos requires specialized software and data, typically including aerial or satellite imagery and a DEM. The resolution of an ortophoto is determined by the original imagery and the accuracy of the DEM.