Another source of potential error in an aerial photograph is relief displacement.
This error arises from the three-dimensional aspect of terrain features and is seen
as apparent leaning away of vertical objects from the center point of an aerial
photograph. To imagine this type of error, consider that a smokestack would look
like a doughnut if the viewing camera was directly above the feature. However, if
this same smokestack was observed near the edge of the camera’s view, one could
observe the sides of the smokestack. This error is frequently seen with trees and
multistory buildings and worsens with increasingly taller features.