(self, vx, vy=None, vz=None, direct=False)
From unit vector direction to position in the projection plane (%s).

        Input:
          - vx: if vy and vz are None, vx[0],vx[1],vx[2] defines the unit vector.
          - vy,vz: if defined, vx,vy,vz define the unit vector
          - lonlat: if True, angle are assumed in degree, and longitude, latitude
          - flipconv is either 'astro' or 'geo'. None will be default.

        Return:
          - x, y: position in %s plane.
From unit vector direction to position in the projection plane (%s).
From unit vector direction to position in the projection plane ( %s ) .
def vec2xy(self, vx, vy=None, vz=None, direct=False):
        """From unit vector direction to position in the projection plane (%s).

        Input:
          - vx: if vy and vz are None, vx[0],vx[1],vx[2] defines the unit vector.
          - vy,vz: if defined, vx,vy,vz define the unit vector
          - lonlat: if True, angle are assumed in degree, and longitude, latitude
          - flipconv is either 'astro' or 'geo'. None will be default.

        Return:
          - x, y: position in %s plane.
        """
        pass
def vec2xy ( self , vx , vy = None , vz = None , direct = False ) : pass