The horizontal and vertical sightlines defined by the Standard are based largely on human factors research and standards. The codification of these angles in the Standard provides support for your argument that you are following ‘best practice’ design rules.
Horizontal Viewing Angle
This is all about geometric distortion of the displayed information – the literature suggests that once the viewer is more than 60° off-axis this distortion is unacceptable and errors increase. Our aim as designers must be to make it easy for users to assimilate information so we must try to avoid unacceptable geometric distortion.
The datasheet for your TV advertises a 178° viewing angle. How much of the football can you see when you sit 89° off-axis?
Note when multiple images are displayed this 60° angle is measured from the farthest vertical edge of the farthest image
Vertical Viewing Angle
Anthropometric data usually shows that comfortable head movement is within ±30° of the horizontal.
The maximum vertical viewing angle is then 30° above the eyeline of the closest viewer.
Whilst we do not specifically define the closest viewer for ADM spaces, the rules of geometric distortion and viewer comfort still apply. In an ADM space, viewers are expected to self-select their viewing position to afford themselves an appropriate view.
What’s a standard eyeline?
In Australia and New Zealand we typically design for a ‘standard’ eyeline around 1200mm (seated) or 1700 (standing) but this will not apply if you’re designing a space for children… or basketballers!
Most countries publish detailed anthropometric data about their own population, and your architect or space planner will have access to it.
Especially when designing for an overseas campus, check the local data to set your design parameters.