|PanGazer – saving images|
PanGazer lets you save the current image file. To do this, select the Save image as ... menu item from the Image menu (or press ‘Ctrl-S’).
This is more than a simple copy of the image because the image’s metadata is updated with new information, if set, and also XMP metadata is added for spherical images if necessary.
The image is saved to the selected file as a JFIF (JPEG File Interchange Format) file with extension .jpg or .jpeg, including all the metadata (Exchangeable image file (Exif) metadata, Extensible Metadata Platform (XMP) metadata, etc.) that was loaded for the current image, updated as detailed below.
You can also save the current image at a smaller size to save space or meet the requirements of other applications. For this, select the Save image at reduced size ... menu item from the Image menu, and then choose from the next menu whether to reduce the image by a factor of 2, 3, or 5 (other options for choosing the new size will probably be added to PanGazer later).
You can then select where to save the smaller image, and once it has been saved it is opened in a new PanGazer window so you can inspect it.
Since the image geometry has been changed, PanGazer cannot simply copy all metadata in this case. Instead, selected “well-known” values are copied from the current Exif metadata (see saving views for the list of copied numbers and strings), and values you have set are included (see below).
PanGazer also lets you create a full-sphere image from a partial-spherical image (e.g., an image that was created from drone photographs that had limited coverage above the horizon, such as the PanGazer ‘starter image’). Some applications require that “360°” images are ‘full spheres’ (that is, the image has data from 90° below to 90° above the horizon).
To make a full-sphere image from a spherical image, select the Save image as sphere ... menu item from the Image menu. PanGazer will then create a new image and fill in any missing data above the top edge (and also one column of data if the X dimension is odd) using deterministic interpolation and smoothing to reduce sharp edges and generally improve the visual appearance. If the image is already a full sphere then do changes to the image will be made.
Since the image geometry has been changed, PanGazer cannot simply copy all metadata in this case. Instead, selected “well-known” values are copied from the current Exif metadata (see saving views for the list of copied numbers and strings), values you have set are included (see below), and new XMP metadata matching the new image is created, also as described below.
Once the new image has been saved it is opened in a new PanGazer window so you can inspect it (and perhaps adjust the viewpoint or other information and re-save it).
Note that if the image being saved is spherical then new XMP metadata is always written. This requires a valid North value (see the Setting North page). If North has not been set then PanGazer will assume that North is at the centre of the image, but will prompt you for confirmation of this before saving.
PanGazer updates the following Exif metadata on saving if the values are known or changed (e.g., set using the geography dialog):
If the image is spherical then new XMP metadata are written, including:
Note that the view angles and zoom are also saved as local persistent data when PanGazer is closed, and those saved values will be used when PanGazer is next started and will override values from the XMP metadata. The initial view values from the XMP metadata are, in effect, used when the file was not the last file viewed using PanGazer.
|PanGazer and these web pages were written by Mike Cowlishaw; Please send me any corrections, suggestions, etc.|
All content Copyright © Mike Cowlishaw,
2014–2020, except where marked otherwise. All rights reserved.
The pages here, and the PanGazer program, are for non-commercial
This page was last updated on 2020-02-04 by mfc.