Get coordinates of extreme points from an area of contact on an iPad

I understand you can't get the area of a contact between an object and the iPad touch screen through the API, but this answer implies you can get "calculated (best estimated) points".

My question is about these calculated best estimated points, could you use them to calculate the longest dimension of the contact area? E.g. if you put you开发者_StackOverflow中文版r hand on it, could you calculate the length of your hand?

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You can use the pathMajorRadius property of the UITouch object, to get an estimate of the touch size. However, you won't be able to see a direction or anything else from that. And this value is somehow inaccurate.

[touch valueForKey:@"pathMajorRadius"]