Apparatus for remote imaging of a terrestrial area, the apparatus comprising: a camera array having a focal length f and a photosensor comprising photosensor pixels characterized by a photosensor pixel pitch P on which light from the terrestrial area is imaged from an operating distance A from the terrestrial area to acquire an image of the terrestrial area; an orthographic image of the terrestrial area having image pixels that image features in the terrestrial area; a terrain map that provides elevation for features in the terrestrial area imaged on the image pixels of the orthographic image; a controller that registers the image of the terrestrial area to the orthographic image responsive to the terrain data; wherein elevation provided by the terrain map has an uncertainty Δβ that satisfies a constraint P≥Δe·f·sin α/A, where a is a maximum oblique angle at which the camera array images the terrestrial area so that registration of the image of the terrestrial area to the orthographic image has an accuracy better than or about equal to the pixel pitch.