I just stitched a spherical 360 x 180 pano, what to do next?
This is the opposite of a detailed tutorial, just some hints and tips in case you stitched your first 360° x 180° spherical pano (possibly without nadir and even without zenith) and you are wondering what to do next.
Viewing such an incomplete "360° x 180°" panorama in a viewer is possible and often profitable
Using a "local viewer" to display the unconverted JPEG panorama like a QTVR
When a pano have an equirectangular format (it was stitched using spherical projection), when the width pixel amount is exaxtly twofold the height pixel amount and when its horizontal FOV corresponds to 360° (zenith and nadir being included or being replaced by black or white pixels, something APP will do by default) you can display it as it is, without any particular transformation, using a stand alone viewer. "Stand alone" means the viewer was not designed to cooperate with a browser (like Internet Explorer or FireFox) and that no HTML code is needed.
This way, provided the pano file is a JPEG (or a TIFF which do not include layers), and provided the pano size is moderate (how large is this depends of your computer video card - please try small sizes first) you can enjoy full screen views where scrolling in any directions is possible and where zooming and scrolling are often very smooth.
Using a local viewer to display your spherical panos at various angles on your computer screen is easy and interesting
- I use the free DevalVR playerU.exe but any of the viewers in the table at the end of this page where "equirect" is indicated should work for that.
- That 360° x 180° panoamas are often viewed using Internet and are uploaded/downloaded as a .mov file using the slightly more efficient Apple QuickTime VR cubic format don't make the local viewers less usefull. For example, I always preview 360° x 180° panos using a local viewer before the final stitch (half size or less is more than enough for previews.) This makes easy to find out any fault near the zenith, the nadir or any other place before the final render. Having to produce a QuickTime .mov file for preview would be both boring and time consuming.
- Placing a local viewer and your equirectangular JPEG on an USB flash drive or a CD is enough to carry and display your 360° x 180° panos on another computer.
Using a converter to prepare Apple QuickTime VR .mov files for HTML browsers
IMPORTANT: selecting the right 360° x 180° file format for Internet and the corresponding plugin(s) is a difficult question I will not attempt to cover there. Apple QuickTime  special VR format, also known as QTVR  was the first 360° x 180° image format. I use pano2QTVR  converter as an example because it is very widely used and its non-pro version is free.
When the .mov file have been saved a double click is enough to launch QuickTime and display the panorama, the 6 intermediary cube faces can be deleted. The pano2QTVR project file is useful when some of the many parameters included in the .mov file are to be adjusted
In the above Qicktime VR window, use Ctrl and Shift to zoom and your mouse to scroll Some important features to note: - what you see is a rectilinear image (straight line are straight) - at the widest zooming I selected the horizontal FOV is larger than 120° so that image is stretched but any other maximum value can be selected by image author.
There are several good reasons for using a particular format like QTVR rather than the usual JPEG format when 360x180 panoramas are to be shown via Internet:
- huge amounts of computation are needed while the viewed image is scrolled and zoomed on the screen, using a special format where the six faces of a cube are embeded makes things easier
- a rough display is possible while the .mov file is still being transmited so that a larger amount of people will wait until the whole file is downloaded and displayed at its full resolution
- a higher compression ratio for the less interesting cube faces (like the ground and the sky) can be used to reduce the file size
- a lot of parameters can be specified to define how the panorama will be displayed, for example a min and a max value for zooming, a min and a max value for yaw and pitch (useful to avoid nadir and/or zenith and/or uninteresting parts being displayed.)
- editing the zenith region, manually stitching the nadir hole or covering it up using a logo is easier when done on the corresponding cube faces (rather than on the "distorted" equirectangular version of the panorama)
- this is the usual practice, that the unconverted equirectangular pano can be viewed directly is not well known.
To Print or not to print ?
There are several reasons not to print 360° x 180° panoramas:
- their 360 degrees field of view must be rendered using an unusual projection (painters and drawers never use it) so that most people will reject the prints as unacceptable, distorted, etc
- printing a 360° x 180° pano at 300 DPI results in a 26" x 13" print and many details visible on screen are barely visible on the print.
Computer screens use 100 DPI, for example viewing a 8000 x 4000 pixels pano displayed on a screen corresponds to viewing a 80" x 40" 100 DPI print. This is because the field of view a 360° x 180° pano encompasses is hundred times as large as the field of view of a 50 mm or equivalent lens: when printing a 360° x 180° pano on a usual paper size like 8.5" x 11" or A4, what you see is not what you captured...
There are several reasons to print 360° x 180° panoramas:
- the graphical composition can be very pleasing
- when very high trees, mounts or buildings are included in the view, equirectangular projection is sometimes preferred to cylindrical projection to avoid stretching in the top parts of an image.
Here is an attempt to list panorama viewers and their main characteristics, more details can be found there: 
DevalVR | free | QTVR | equirect | none | | | Windows Flash Panorama Player | 40 € | | equirect | Flash | Linux?| Mac | Windows freepv | free | QTVR | | | Linux | | Windows GLPanoView | free | QTVR | equirect | OpenGL | | | HD View | beta | | | | | | Windows Immervision | free | QTVR | JPEG | Java Flash | Linux | Mac | Windows PangeaVR | free | QTVR | equirect | OpenGL | | Mac | Panorado aplet | .... | | equirect | Java | | | Windows Pano2QTVRPro+FlashPack | 55 € | | | flash | | ? | Windows PTViewer | free | QTVR | equirect | Java | Linux | Mac | Windows Quicktime VR | free | | | Quicktime | | Mac | Windows SPi_V | free | QTVR | equirect | Shockwave | | Mac | Windows
DevalVR | free | QTVR | equirect | none | | | Windows Flash Panorama Player | 40 € | | equirect | Flash | Linux?| Mac | Windows FSPviewer | free | | equirect | DirectX | | Wine| Windows panoglview | free | | | | Linux | Mac | Windows Panorado | 20 € | QTVR | equirect | DirectDraw | | | Windows Quicktime VR | free | | | Quicktime | | Mac | Windows SPi_V | free | QTVR | equirect | Shockwave | | Mac | Windows
PanoPreviewer | $20 | | equirect | Photoshop plugin | Mac |
 Flash Panorama Player
 GLPanoView (development stopped)
 HD View (beta)
 Quicktime VR
No doubt some useful programs are missing in the above list and some characteristics are inexact, so that corrections and additions are welcome! --
GURL 00:35, 10 July 2007 (CEST)