What is orthorectification/mosaicking of aerial photography?
When image data (aerial photography) is collected from the plane two elements of distortion impact the image, one being the topographical variation of the landscape, and two being the tilt of the aerial sensor. These factors affect the distance with which features on an aerial photograph are displayed. The more diverse the landscape, the more distortion is inherent in the photo. The process of rectifying involves the creation of a Digital Elevation Model, or DEM is created and used to perform the image orthorectification. The aerial photography is aligned with the DEM and is then run through a series of computed algorithms to remove the distortion. To create countywide seamless orthophotography, the images are mosaicked. Mosaicking is the process where images with the same projection datum, ellipsoid, and scale are edgematched, thereby creating a seamless dataset of orthophotography.
