Transcatheter aortic valve implantation (TAVI) is one of a series of catheter intervention procedures to deliver a prosthesis, in this case prosthetic valve, two structures, the aortic annular plane and the tip of the delivery catheter, must be are optimally visualized by the surgeon and in many instances there exists only one viewing angle for this. The preferred viewing angle being determined by obtaining angulation data for two views perpendicular to first and second planar structures, calculating normal vectors of each of the first and second planar structures using the angulation data, calculating a perpendicular unit vector using the normal vectors, and calculating angulation of the unit vector to establish the preferred viewing angle.