PanGazer – introduction
PanGazer is an image viewer for both 360° spherical images (as captured by 360° cameras and drones) and regular ‘flat’ images. PanGazer automatically detects spherical images, so there is no need for a special ‘spherical’ viewer or mode.
Uniquely, PanGazer preserves the location, direction of view, focal length, and other known details of a view when saved. Unlike a simple screenshot this means that you can compose and save multiple ‘flat’ images from any spherical image and each will have the correct geographical and photographic metadata for that particular view.
See below for a full list of features. PanGazer is free (and advert-free); it runs on Windows and also on Windows emulators on Linux and MacOS.
The screenshot below is a view of a 360° panorama; this ‘starter image’ is shown when you first start PanGazer (the source image is shown at the bottom of this page). Click on the screenshot to see a more detailed version.
PanGazer screenshot – click for a more detailed image
Please click on ‘Getting started’ on the left for an overview of the application, or on the other menu items for more specific information.
I am currently actively developing PanGazer, so do please send me suggestions for improving PanGazer (click here for contact details »). PanGazer has been written from scratch (sharing most of its 37,000 lines of code with my MapGazer » application), but has been inspired by and depends on the work of many other people; please read my thanks, here.
PanGazer features
- PanGazer lets you view a spherical panorama as though from the
camera viewpoint, then lets you snapshot (save) an image
as seen. In other words, you can compose and save multiple ‘flat’
images from any spherical image.
Unlike a simple screenshot, PanGazer snapshots include data such as the lens focal length (calculated from the actual view) and also, if available, the location, bearing, camera tilt, and other data derived from the original image. This allows snapshots to be presented correctly, and ‘snapshots from snapshots’ will also have the correct data.
- PanGazer automatically detects 360° spherical panoramas
– even if metadata (e.g., Exif) has been removed. The
correct horizon will be set for ‘part-spherical’ panoramas (e.g.,
drone panoramas, which typically cover only 40° above the horizon).
You can override the image projection when possible.
- A number of shortcut keys are provided for common actions.
In particular, the Escape (Esc) key toggles between full-screen
and window views, and the Space Bar toggles between showing
your selected status and overlays and hiding all status and overlays.
- You can use PanGazer to view almost any image (not just panoramas);
again you can snapshot or save any view, which makes it much
easier to gauge the composition than using a ‘crop tool’. Image
data (effective lens focal length, viewpoint, geography, etc.) are
calculated and included in the snapshot metadata where possible.
- Part-spherical panoramas can be filled to make full-sphere
panoramas, for use in social media, etc. In addition, nadir
fill (or zenith fill) can be applied, e.g., to hide a tripod or
person holding a 360° camera. In all cases, only data from
your image are used (unlike some “AI” fillers that use data from
others’ images).
- Multiple views (windows) are supported – you can view different
images, or the same image, from multiple angles and zooms at the
same time. For example, you can compare still images with views
from a 360° panorama. You can also explicitly set the aspect
ratio of any window (to compare compositions, for example, or
to suit a particular display or print size).
- If the image location is known or set you can show its location
on maps, including Google satellite or regular Maps, MapGazer,
or Google Earth. You can also show the view direction using
a GPX or KML viewer if North has been set, or save the image location
as a GPX or KML file.
- PanGazer emphasises and simplifies the viewing and editing of image
geographical data; you can set or edit the geographical values
(location, elevation, True North bearing, and tilt), which will then
be saved in the image Exif metadata. For spherical images, additional
values (including initial camera stance and zoom) are saved in the
image XMP metadata.
If the bearing or tilt are known (from Exif or XMP metadata) or set, compass points (N, S, etc.), a North line, and tilt angles can be overlaid on the image to indicate direction (see the screen shot above for an example). You can toggle all overlays on or off using the Space Bar. Further, you can overlay a 15° grid on spherical images.
- In general, PanGazer tracks image geometry; for example,
when zooming in while viewing an image the pel (pixel) ratio (the
number of pels used on-screen for each pel in the original image)
is displayed, along with the equivalent focal length of the view
you are seeing and the angles of view. You can also explicitly
set the zoom to 100% pel ratio.
- Strong viewing enhancements (brightness, etc.) are available
to help you identify features of interest.
- PanGazer uses a fast multi-threaded implementation of the gnomonic
projection which reduces apparent distortion of horizontals and
verticals. Interpolation is used to improve the display of zoomed
or low-resolution images.
- The user interface (e.g., dragging left or right) works the
same way on all images, unlike some 360° image viewers. Further,
the user interface is modeless; you do not have to ‘enter panorama
view mode’, for example.
- The ‘retro’-style menu bar allows a bigger visible image.
Also, the menu bar and/or title bar can be hidden, or you can view
all images and panoramas full-screen (use Escape to toggle
between full-screen and a window).
- Very large images (up to the 65K×65K limit – 4 GigaPixels – of JPEG images) can be loaded, provided that sufficient RAM memory is available. In most cases a progress bar will be shown if loading a JPEG image will take more than a second.
PanGazer requirements
PanGazer runs on a Windows personal computer (PC, laptop, or tablet, running Windows 7 or later); it also runs on Windows XP and Windows emulators on Mac OS and Linux, but is not fully tested in those environments.
Both 64-bit and 32-bit executables are included, along with a ‘stub’ 32-bit executable that will start the best main executable on any version of Windows. The 32-bit executable will run on 32-bit Windows systems but large panoramas and images (e.g., more than 12,000 × 6,000) may fail to load due to memory fragmentation. With either executable you may have difficulty loading large images if you do not have several GigaBytes of RAM. It is recommended that you run a 64-bit version of Windows if possible.
PanGazer does not require an internet connection to run (except for internet-specific features); in particular, all the Help pages are included in the package and are accessible when offline.
PanGazer lets you load and view many types of images (JPEG, PNG, GIF, BMP, TIFF, etc.). When saving an image, PanGazer uses JFIF (the JPEG File Interchange Format, file extension .jpg or .jpeg) so that metadata (geolocation, camera bearing, tilt, zoom, etc.) can be saved with the image using Exif and XMP metadata.
Here is a reduced version of the plain (un-projected) PanGazer starter image, stitched from 34 images taken using a DJI Mavic Pro drone (the download package includes a much larger and more detailed image). As a plain image it is quite distorted (the entire bottom row of the image represents a single point).
A 360° source image (reduced in size 24×)
You can also view the starter image using Google Maps on a PC (or on the Google Street Map app on a phone): search for “Bejes, Spain”, click on the ‘little yellow man’ and scroll right to 225m due East of the car parking area at the southern entrance to the village (and about 100m SSW of the church); you should see a small blue circle. Clicking on the circle should display the panorama. This upload of the starter image, saved as a sphere, was done using the Google Street Map app from a mobile phone; see the Sharing Images page for more details.