The Spherical projection is used for Environment textures and IESAn IES light is the lighting information representing the real-world lighting values for specific light fixtures. For more information, visit http://www.ies.org/lighting/. Light distributions. It performs latitude-longitude mapping for the UV coordinates, and for Procedural textures, the W coordinate is the distance from the origin.
Figure 1: Octane VOP Network example
Figure 2: Spherical projection