Image to Map Rectification

By linking an Orthophoto to its corresponding Map image (Image to Map Rectification), cultural features can now be used in a thematic context (related to other data in a GIS). These cultural features now have actual map coordinates, rather than pixel x, y locations, resulting in accurate distance and bearing calculations.
Errors can occur with the GCP method of rectification. An image may lack any discernible features to use as control points. User error in the placement of GCP's (misinterpretation of features). The Orthophoto is distorted beyond the point of rectifying.