Spherical projections work with 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 U and V coordinates. For Procedural textures, the W coordinate is the distance from the origin.
Figure 1: Using Spherical projection to map a Texture to a sphere
When using an Image texture to light a scene with the Sun And Sky node, spherical mapping combined with a Transform node rotates and translates the Environment sphere's Texture.