Equirectangular Image

An equirectangular image is the standard digital format for storing and sharing 360° spherical photographs. The format takes the full sphere of visual information surrounding a 360° camera and projects it onto a flat rectangle using a simple geographic coordinate mapping: horizontal position in the image corresponds to azimuth angle (longitude), and vertical position corresponds to elevation angle (latitude).

The resulting image looks distorted to a viewer who sees it as a flat picture — the top and bottom regions are heavily stretched, as they represent the poles of the sphere compressed into the same image width as the equator. When the image is loaded into a 360° viewer, however, it is re-projected onto the inside of a sphere, and the distortion disappears. The viewer can then look in any direction within the space.

Equirectangular images are output natively by virtually all consumer and prosumer 360° cameras — including the Insta360 ONE series, Ricoh Theta, GoPro Max, Kandao Qoocam, and Samsung Gear 360. This standardisation means that equirectangular images captured by any of these cameras can be loaded into any compatible 360° viewer, uploaded to platforms like pin360, or shared directly via links without any specialised software.

The typical resolution of a modern equirectangular image is between 5.7K and 11K pixels across (5760×2880 to 11008×5504). Higher resolution is important for inspection purposes, where the reviewer needs to zoom into a small area of the image — a crack on a beam soffit, for example — without the image becoming too pixelated to be useful. At 5.7K, a 1° field of view corresponds to roughly 16×16 pixels, which is adequate for general documentation. At 8K or above, fine detail such as crack widths of 0.3–0.5mm can be identified at close range.

For engineering documentation workflows, the equirectangular format matters because compatibility determines whether images can be incorporated into a spatial documentation system. Any platform that accepts equirectangular JPEGs — including pin360 — works with images from any compliant camera, without proprietary hardware requirements or proprietary file formats.