Calculating apparent size

[GVP]

Greetings!

Does anyone know if there is a formula for calculating the apparent size of a sign from a given distance? For example, how big would a 4'x8' panel appear to the observer from, say, 100ft away? This kind of math is outside my comfort zone, but it sure would be handy to be able to convey the info to customers who need to know what it would look like?

Thanks.

 

[2B]

sounds like you are needing a visibility chart, this will help to know the height of the needed letter for the distance and the speed factor for drivers.

https://www.google.com/search?q=rea...=org.mozilla:en-US:official&tbm=isch&imgdii=_

 

[bob]

Objects diminish in size over distance linearly. An object that is at X distance always appears exactly 1/2 the size it appears at a distance of X/2.

In other words an object at 100 feet appears at 1/2 the size it would appear as at 50 feet, 1/4 the size that it would be at 25 feet, 1/8 the size it would be at 12.5 feet, etc. Ergo, a general expression of relative size might look something like...

apparent size at 100 feet = X/100*S

where X is the number of feet at which the object appears to be S in size. I.e. if an object appears to be 10 feet wide at 5 feet away then it will appear to be 5/100*10 feet wide at 100 feet distant or .05*10 or 6" wide.