The most common type of vertical photo is called a "near
vertical". Near verticals are done when a straight down
view of a site is desired, but GIS information and engineering
data are not required for your application.
Single image near verticals are a cost effective option for areas from
approximately 1.0 x 1.5 miles down to individual parcels and lots.
Multiple near vertical images can be stitched together to cover larger
areas, but it should be noted that the resulting image will not be as
accurate as a photo map or a true vertical aerial survey.