astro_field.py 文件源码

def _calcArea_(self, v1, v2):
        """
        Private method to calculate the area covered by a spherical
        quadrilateral with one corner defined by the normal vectors
        of the two intersecting great circles.

        INPUTS:
            v1, v2:  float array(3), the normal vectors

        RETURNS:
            area: float, the area given in square radians
        """
        angle = self.calcAngle(v1, v2)
        area = (4*angle - 2*np.math.pi)

        return area