hi model

I've got lots of questions about this:

(i) Why have you calculated the distance between the points?

(ii) What language is this in?

(iii) double ?  Does this calculate with double precision?

(iv)  I got confused  about what angle you wanted.  I've now made a diagram (see below).  Please confirm this is the angle you want.

Your formula for the angle seems to be

I thought you wanted

(v) The function atan will return the 'principle value' ;  most likely this will be an angle between -90 and +90.

If you want to get a positive angle for any co-ordinates, you'll need to test the sign of the answer rather than worry about the size of the angle.

(vi) I do not understand the output "move to right/left side" means.  Please explain what you are trying to achieve here.

(vii)  You have an angle of 171 for these co-ordinates.  I make it 10.9 degrees.  Are we talking about the same thing?


Please post again, 

Bob

Last edited by bob bundy (2011-08-11 18:23:22)

Well @Bob , I changed my condition regarding angle direction to eat side or west side .

if( angleInDegree <=90 || angleInDegree > =0)
    {
        cout<<"move to right side.."<<endl;
    }
    else if ( angleInDegree <=180 || angleInDegree >= 91 )
    {
        cout<<"move to left side.."<<endl;
    }


Is that now ok ?

Last edited by model (2011-08-17 18:33:57)

Hi Bob,

I did as you said . about the  right and left side ,
But my finger is continuously moving from left to right in different angles.

and i set

if x1-x2 > 0 then Print 1( right side movement )
else if x1 -x2 < 0 then Print -1 ( left side movement mean)
else  Print 0 (moment in no specific direction .)

But Since my  hand or finger whatelse moving in different direction. So, i think angle is also important.

btw, Can you please tell me formula for angle  between 4 points


i found this formula:

abs(p1.y-p2.y)/sqrt((p1.x-p2.x)*(p1.x-p2.x)+(p1.y-p2.y)*(p1.y-p2.y));

I think above formula is good to find the angle in specific  direction and distance .
What do you say ?

Hi  Bob,

Sorry, I did not read  your recent  message .

As i told you, I am doing project hand motion direction .  i need to find an direction  of my hand motion . like moving  hand angle in which quadrant  .

I got an idea .

If my hand have location current and previous say  A(x1,y1) and B(x2,y2) .. then to find an angle i need third  point in plane .

So, i am thinking that if we consider Origin as third point say O(x3,y3) .

then using vector concept . we can get the hand angle in plane .
Right  ? ok ?

And we can get two vectors says OA and OB ,. and then we can find angle of  hand motion . right ???

Is that ok ??
Please guide me thanks
Model

Last edited by model (2011-08-18 03:18:30)

hi model

project hand motion direction

Sorry, but I don't understand what you mean.

Is this part of a bigger program?  If so, what is that about?

Do you have an algorithm / flow chart / object diagram to show how this fits together?

I'm not sure how to help you because I'm not sure what to want to achieve?

Bob