I can- my vector field will associate a vector with any point on the x-y plane and it will-- it can be defined as some function of x and y, which I'll call that P some function of x and y times the i unit vector so it says what the i component of the vector field is for any x and y point and then what the j component, or what we multiply the j component by or the vertical component by for any x and y point so some function of x and y times i plus some other scalar function of x and y times j and so if you give me any point there will be an associated vector with it any point there is an associated vector depending on how we define this function.