Stereo photography is produced by taking imagery with at least a 60% overlap at 90° to the flight line in either the vertical or oblique axis. This type of photography has unique properties which can be exploited using a stereoscope (an optical device designed to ensure that each eye views only one of the images) or a suitable G.I.S. package.

G.I.S. (vertical)
Height data can be established from stereo photography using a suitable software package, height values (postings) can be assigned in grid form over the stereo part of the image at desired distances to produce a digital terrain map (DTM) or height map.

Line Of Sight (vertical)
Accurate line of sight studies can be undertaken using stereo imagery. The technique can be used to ensure clear line of sight for mobile phone masts and microwave links or where access to an area is restricted or the terrain is inaccessible or impractical. It can also be used to assist security agencies when approaching potentially dangerous or sensitive locations by identifying 'dead' or 'safe' ground.

Dead Ground Studies (oblique)
This allows a photographic interpreter to determine 'dead' or unseen ground from a given location within the imagery. This is ideal for security forces planning, 'in field' movement as well as security equipment positioning.