image processing using matlab

[karmax]

hello,
     I have undergiven image .In this i know all the cordinates of blue points.first task that i have to perform is first i have to find out the nearest blue point from center.then taking  refernce of that point.i need to locate all point.for example i taken nearest blue point to o.then all the lines connect to that point we have to find and all the points on line taken as A,B,C.example if point o is connected to 3 lines then points on 1st line taken A.2nd on B.3rd to C...The main problem that i am facing is i find out the nearest point but i dont hw to recognise which lines are connected to that point .please help me outhttp://img7.imageshack.us/img7/968/92341708.jpg