Aspect ratio = ((wing span)^2/surface area)
So a hypothetical 12m kite shaped like a flat rectangle when unrolled, with a 5.4 AR has a span of 9.2m and chord of 1.3m.
Really kites aren't shaped so simply, and other factors are considered but that's the idea.
Formula is correct, and the easy way to measure (but numbers are not...)Aspect Ratio = span / average width.
Area = span * average width.
Meaning AR = span^2 / area.
So your 12m2 kite with an AR of 5.4 has a span = sqrt(AR*area) = sqrt(5.4*12m2) = 8.0 meter.
And an average width = span / AR = area / span = 1.49 meter.
I dont agree that "numbers" are just marketing, so you simply lay your kite out flat on the ground and measure the span from tip to tip, and use the nominal size printed on the kite to calculate the AR.
That works fine - and most kites are relatively okay in their size measurement, is my experience.
Even if a 12m2 kite actually was 13m2 - the error in AR calculation will only be about 7 to 8% which is not bad really
Of course, like others point out - the AR is only one parameter, as whether the area is in the middle or the tips, and how flat/c the kite is, means much more.
But for those interested in this number, using the written area and the measured span is fine IMO
Agree that it is also interesting to measure a kite up precisely yourself, if you want to know the exact size.
Why do so many use the term "12m" about a 12m2 kite ?
The word constellation 12m does not exist as an area measurement in Danish nor German, and also lacking in most other languages, so why do so many english speaking say "12m" ?
Simple lazyness, or old bad habits or ?