A. - Aerial photos are 9"x9" black and white photographs taken from an airplane looking straight down. Each photograph can cover a small area or several square miles. Our topo maps are one square mile (one section) showing contours in 4 foot intervals along with streets, boundaries and other features labeled for identification. Ortho photos are a combination of both aerial photo and topo map but with added features. Like the topo maps, the ortho photos are one square mile with 4 foot 1contour intervals, streets, boundaries, etc., plus aerial photo imagery as a back drop. On the ortho photo the aerial photos have been rectified allowing them to be scaleable.