aurum34 : that number is the percentage of confidence. It measures the "similarity" of the gesture you just draw against the gesture in the database.
You need to do some tests yourself to know at what limit you consider the gesture to be the same. It depends on the user, and the kind of gesture.
For example, "a square", with a number above 0.75 means it's very likely to be a square. But, for example, for a circle, perhaps you need to set the number at 0.4 (for the "circle" gesture only).