What Is a Spherical Panorama? A Beginner's Guide
A plain-language introduction to spherical panoramas: horizontal and vertical coverage, equirectangular images, capture and viewing methods and common challenges.
By Panorama 360 Team · · 5 min read
In this article
A spherical panorama is an image that records the view in every direction from a single point: all the way around you and from straight up to straight down. If you open one in a suitable viewer, you can look at the ceiling, the floor or any wall, as though you were standing where the camera stood. This beginner's guide explains the idea, how such images are stored and captured, how to view them and why they are harder to make than ordinary panoramas.
The definition: coverage in two directions
Most panoramas are wide: they extend far horizontally but only a little vertically. A spherical panorama extends in both directions.
- Horizontal coverage is how far around you the image goes. A full turn is 360°.
- Vertical coverage is how far up and down it goes. Straight up to straight down is 180°.
A spherical panorama has 360° × 180° coverage. If either number is smaller, the image is not a complete sphere. A panorama that wraps all the way around but covers only a band of the view has 360° horizontal coverage but far less than 180° vertical. We call that a horizontal 360° panorama, and it is a different thing. Our article on panorama versus 360° photo compares the types.
How spheres are stored
A sphere cannot be flattened without distortion, which is the same problem mapmakers have with the Earth. For panoramas, the standard answer is the equirectangular projection: horizontal position maps to longitude, and vertical position maps to latitude. A full sphere becomes a flat image twice as wide as it is tall. Near the horizon, things look natural. Near the top and bottom edges, which correspond to the points straight up and straight down, content is stretched across the full width. The Wikipedia page on the equirectangular projection shows maps drawn this way.
That distortion is not a flaw in the picture; a viewer reverses it by wrapping the image onto the inside of a sphere around you.
To let software recognise such a file, spherical JPEGs include metadata. Google describes the fields in its spherical metadata specification. The fields can also describe a panorama that covers only part of the sphere, using a cropped-area description, which is how a partial panorama can be stored honestly instead of being passed off as a full sphere.
What you need to capture one
A phone camera sees a narrow field of view, so a full sphere needs many photos taken in a planned pattern:
- A ring of photos around the horizon.
- A ring tilted upward.
- A ring tilted downward.
- One photo straight up and one straight down.
Each photo must overlap its neighbours, usually by around a third, so that software can match details between them. With Panorama 360 this typically means about 25 to 35 photos. The phone's motion sensors track where the camera is pointing, so the app can guide you to the next position and show a coverage map of what is still missing.
You also need to rotate around the phone rather than move it, because moving the camera sideways causes parallax, and nearby objects will not line up.
How the photos become one image
Software combines the photos in a few steps. It finds matching details between overlapping photos, estimates how the camera turned, projects the images onto a sphere, balances their brightness and blends the overlaps. The approach is described in the research paper Automatic Panoramic Image Stitching using Invariant Features, and our article how photo stitching works explains it in everyday language. Panorama 360 does this on the phone.
Viewing methods
You can look at a spherical panorama in several ways:
- Drag to look. On a phone or computer, drag to rotate the view and pinch or scroll to zoom.
- Motion viewing. Some phone apps let you move the phone to look around.
- VR headsets. A headset maps head movement to the view.
- Embedded viewers. Websites can embed a viewer, such as the open-source Pannellum.
Panorama 360 has a built-in viewer you control by dragging, pinching and double-tapping to reset. Partial panoramas are labelled so that you know what was and was not captured.
Where spherical panoramas are used
- Real estate, to show the size and layout of rooms.
- Hospitality, to show rooms, restaurants and venues.
- Travel and landscapes, to keep a whole view.
- Retail and showrooms, to let people explore a space.
- Virtual tours, where several panoramas are linked together.
These are common uses, not promises of results. Whether a panorama helps depends on the subject and on its quality.
Common technical challenges
- The poles. Directly up and down, photos converge, so small errors are easy to see.
- Parallax. Near objects shift if the camera moves.
- Movement. People and traffic appear twice or half cut.
- Exposure. Windows beside dark walls are hard to balance.
- Low-detail areas. Blank ceilings and clear sky give the matcher nothing to hold on to.
- Your own shadow or feet. A handheld floor shot often includes you.
A short glossary
- Zenith and nadir: the points straight above and straight below you.
- Field of view: how much of the scene a lens sees at once.
- Overlap: the part of a photo that is also in its neighbour, used for matching.
- Equirectangular: the flat 2:1 format used to store a sphere.
- Parallax: the apparent shift of near objects against far ones when the viewpoint moves.
- Stitching: combining overlapping photos into one image.
- Partial panorama: a panorama that does not cover the full sphere.
Why spheres are worth the effort
A sphere takes more photos and more time than a flat panorama, so it is worth asking whether you need one. If viewers will want to look at the floor, the ceiling or the sky, or if you plan to link panoramas into a tour, a sphere is the right format. If the interesting content is at eye level, a horizontal 360° is quicker and often looks just as good. Matching the format to the purpose saves time and avoids disappointment.
Reading a coverage map
A coverage map is a small flattened view of the sphere that fills in as photos are taken. Large empty patches mean missed areas, usually near the top and bottom, where the camera has to point steeply. Fill these in before you finish, because a missing patch cannot be repaired later without retaking photos from the same spot.
Where to go next
If you want to try capturing one, read how to take a 360° panorama photo with your phone. To see how the app handles spheres and what a complete one requires, visit the spherical 360° panorama page, and for the whole app see the 360° panorama camera app page. Panorama 360 is coming soon to Android and is not on Google Play yet.
Frequently asked questions
What does 360° × 180° mean?
It means the image covers a full turn horizontally (360°) and everything from straight up to straight down vertically (180°).
How do I view a spherical panorama?
In a viewer that understands the format, by dragging, using the phone's motion sensors in some apps, or with a VR headset. A flat view of the file looks stretched.
Can a phone take a spherical panorama?
Yes, by taking many overlapping photos in rings plus up and down. It takes longer than with a dedicated 360° camera and needs careful technique.
Keep reading
- 5 min readPanorama vs 360° Photo: What's the Difference?Not every wide image is a 360° photo, and not every 360° photo is a sphere. Here is how the formats differ and how to choose between them.
- 5 min readHow Photo Stitching Works: From Multiple Images to One PanoramaStitching finds the same details in overlapping photos, works out how the camera moved and blends the result. Here is each step and where it goes wrong.
- 5 min readCan You Create 360° Photos with an Android Phone?An Android phone can produce 360° photos by taking and stitching many shots. Here is how it works, what limits the quality and how it compares with a dedicated camera.
360° Panorama Camera AppSpherical 360° PanoramasCreate a 360° Virtual Tour