Equirectangular map projection of the Earth
Equirectangular projection — the same mapping used for 360° video and dome content conversion · Photo: Strebe · Source · CC BY-SA 3.0

What is it?

Equirectangular projection (also called lat-long or spherical projection) maps a complete 360°×180° sphere onto a flat rectangle with a 2:1 aspect ratio. Longitude maps to the horizontal axis, latitude to the vertical. The result is the same projection used in world maps — heavily distorted at the poles, accurate at the equator.

Equirectangular vs. Domemaster

PropertyEquirectangularDomemaster
CoverageFull sphere (360°×180°)Hemisphere (180°×360°)
Aspect ratio2:11:1 (square)
Pixel wastePolar stretching~21% (corners)
VR compatibleYes (native)Needs conversion
Dome compatibleNeeds reprojectionYes (native)

Many producers now master in equirectangular at 8K×4K or 16K×8K, then derive dome and VR outputs from the same source. Tools like ffmpeg, Blender, and DaVinci Resolve can convert between the two formats.

Common Resolutions

  • 4K equirect — 3840×1920 (basic VR, YouTube 360°)
  • 8K equirect — 7680×3840 (professional VR, fulldome conversion)
  • 16K equirect — 15360×7680 (Cosm venues, Sphere-class)

Relevance to Fulldome

Equirectangular is increasingly used as the universal master format because it covers the full sphere — content can be cropped and reprojected for any dome geometry, VR headset, or flat screen. Cosm venues with hyper-hemisphere apron extensions (going below the springline) benefit from full-sphere equirectangular masters.

See also: Domemaster → · Fulldome → · Resolution →

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