PanGazer logo PanGazer – saving images

Introduction

Download PanGazer


Getting started

General settings

Setting North

Saving views

Saving images

Sharing images

Image geography

Show image location

Overlays

Enhancements

Aspect ratio


Making panoramic images

Keyboard shortcuts

Command line options

The gnomonic projection

Thanks

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 will open a dialog box that lets you change the size of the image before saving and also lets you expand a part-spherical panorama to a full sphere.

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.

When saving, the image is written to the selected file as a JFIF (JPEG File Interchange Format) file with extension .jpg or .jpeg, including the Exif (Exchangeable image file) metadata, XMP (Extensible Metadata Platform) metadata, and any other metadata that was loaded for the current image. The Exif and XMP metadata might be updated or replaced, as detailed below.

Here is a screenshot of the Save image dialog for a part-spherical image (for non-spherical images, or a full-sphere image, the line with the checkbox is replaced by a description of the image type):

PanGazer screenshot showing save dialog

PanGazer screenshot showing save dialog

In detail:

  • If you make no changes to the input fields or the checkbox then the image will be saved as-is, with updated metadata if you have changed the view, image geography, etc.

  • You can adjust the size of the image by editing either the X: or Y: values (PanGazer will update the other to maintain the same aspect ratio, providing that the edited value is valid). You can reset the X and Y values to those of the current image by clicking the Reset button.

    Note that if the image is a full-sphere panorama then the X value must be even (so that the Y value can be exactly half that).

  • You can convert the image to a full sphere if it is a part-spherical panorama (e.g., an image that was created from drone photographs that had limited coverage above the horizon, such as the PanGazer ‘starter image’). To do this, check the Expand this image to full sphere before save checkbox.

    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.

    This is useful for some applications which require that “360°” images are ‘full spheres’ (that is, the image has data from 90° below to 90° above the horizon) – see Sharing Images for more details.

Having made any desired changes, click the Save button. This will create a resized and expanded image, if necessary (this may take a few seconds), and then ask where it should be saved using the usual Windows save dialog.

If any changes to the image geometry (size) were made:

  • The saved image is opened in a new window so you can check it (and, if spherical, perhaps adjust the viewpoint or other information and re-save it).

  • PanGazer cannot simply duplicate the original Exif and XMP metadata. 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 or updated (see below). If the image is spherical then new XMP metadata matching the new image is written, also as described below.

Saved data

PanGazer updates the following Exif metadata on saving if the values are known or changed (e.g., set using the geography dialog):

  • latitude and longitude of the image (camera location)

  • elevation of the image (camera elevation above mean sea level)

  • bearing of the centre of the image (relative to True North; 0° to, but not including, 360°).

  • the pitch (tilt) of the centre of the image (0° if at the horizon, positive above or negative below).

If the image is spherical then new XMP metadata is written, including:

  • image geometry (X and Y for equirectangular full sphere, etc.)

  • the bearing of the centre of the image (relative to True North; 0° to, but not including, 360°); 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.

  • the pitch (tilt) of the centre of the image (0° if at the horizon, positive above or negative below)

  • the view angles (bearing and tilt) and zoom setting currently in use; these will be used for the initial view of the image when first loaded – that is, the current bearing of the view, etc., will appear at the centre of the initial view window whenever the saved image is loaded by PanGazer (or other applications that use the XMP initial values metadata).

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 use only.
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This page was last updated on 2020-02-20 by mfc.