Which panorama projections are most useful, and when should you use each one?

The “best” projection depends on the scene, field of view, and how the pano will be viewed. Most projections exist to control how distortion is distributed.

Common useful choices:

• rectilinear: Best for narrower views when you want straight lines preserved, but it stretches badly at very wide angles.
• cylindrical: Good for wide horizontal panoramas; verticals stay more natural than with rectilinear for broad sweeps.
• equirectangular: Standard choice for full 360x180 spherical panoramas and many virtual-tour workflows.
• cubical/cubic faces: Useful for interactive viewers, virtual tours, and some 3D workflows.
• spherical probe / hemispherical: Often used for environment maps and specialized rendering uses.
• mercator and similar variants: Mainly useful when you want to emphasize/de-emphasize certain regions of the panorama.
• compressed/squeezed rectilinear and other variants: Helpful when you want more control over edge stretching while keeping a rectilinear look.
• little planet / stereographic-style outputs: Mostly creative effect rather than neutral presentation.

A practical rule: choose based on output purpose. For standard wide scenic images, cylindrical or rectilinear are common. For full immersive panos, use equirectangular or cubical. For 3D/environment mapping, use spherical, cubical, probe, or hemispherical formats.