PanGazer logo PanGazer – overlays

Introduction

Download PanGazer


Getting started

General settings

Setting North

Saving views

Saving images

Sharing images

Image geography

Show image location

Overlays

Spherical fills

Enhancements

Aspect ratio


Making panoramic images

The gnomonic projection

Coordinate formats

Keyboard shortcuts

Command line options

Saved metadata

Thanks

PanGazer uses ‘status’ text fields to show camera settings, etc. (see the settings page).  In addition, it can overlay data on the image that are directly related to the image itself rather than being simply numerical values. 

You can toggle the display of all the overlay and status displays currently visible in a view using the Space Bar (for from the View or pop-up menus); this overrides individual settings.

Currently the following overlays are available:

  • Compass points – if the bearing of the image is known (see setting North), this adds points of the compass across the top of the view to indicate the direction of view.

  • North line – if the bearing of the image is known (see setting North), the North point (N) is shown along with the line along which all points are due North.

  • Tilt angles – if the horizon of the image is known, this adds tilt angle values at the left of the view.

  • Grid – overlays a grid at 15° intervals on spherical images; this will be aligned to North (if known) or otherwise is aligned with the centre of the image.

If the bearing or horizon is not known you can set it, as described below.

Here is a view showing the Compass points and Tilt angles overlays (a view showing the grid is at the bottom of this page):

PanGazer screenshot showing overlays

PanGazer screenshot showing overlays

Compass points

PanGazer lets you set where North is for any image.  Once North is set, as detailed on the Setting North page, PanGazer can show the bearing of the cursor and can also overlay compass points (‘N’, ‘S’, ‘SW’, etc.) at the top of the view to help give a sense of direction – as shown in the screenshot above.

The overlaid compass points will move appropriately as you change viewpoint and zoom.  You can turn them off or on by clicking the Settings → Overlays → Show compass points menu item.

The view bearing is calculated at the position that the compass points are displayed (near the top of the view rather than at the centre point of the view).  This is so the bearings remain static relative to the displayed image as the view is panned left or right.

North line

The North line is only shown if North is set and and the North point (N) would be visible at the top of the screen.  Turning on the North line by clicking the Settings → Overlays → Show North line menu item shows the North line (and the North point, if not already shown by the Compass points overlay).

Tilt angles

The tilt of the image is the vertical angle (pitch) of the centre of the image relative to the horizon (positive is above the horizon) with a range from −90 through +90 degrees.  For spherical images the position of the horizon is fixed and is calculated from the geometry of the image (the bottom edge of the image is at −90 degrees).

For all other images (360 or not) you can set, edit, or delete the horizon position; as for setting North, there are two ways to set the horizon position:

  1. You can use the Image Geography dialog to set (or delete) the tilt of the centre of the image.

  2. If the horizon is visible in the image, right-click on it and select Set horizon on the pop-up menu; you should then see the tilt angles at the left of the view.  If their position is wrong, just try again (or use the Image Geography dialog to adjust or delete the value).

The tilt overlay shows the tilt at the centre point of the view (not the point where the overlay is displayed) unless the Grid is being displayed, in which case the tilt overlay matches the grid lines.

You can turn the tilt angles overlay off or on by clicking the Settings → Overlays → Show tilt angles menu item.

Grid

The grid is overlaid on spherical images at 15° intervals; this will be aligned to North (if known, see above) or otherwise is aligned with the centre of the image.  In either case, 90° lines are shown in a red and others in a yellow (see below).  Near the poles the grid lines are faded out so as not to obscure image detail. You can turn the grid overlay off or on by clicking the Settings → Overlays → Show grid menu item, or by pressing ‘Ctrl-g’.


Notes:

  1. Once the North point or horizon has been set it will be recorded in the image file (in its Exif metadata, and in XMP metadata too if the image is spherical) if the image is saved (using Ctrl-s, Ctrl-r, or Image → Save image as..., etc.).  When it is next loaded the bearing and/or horizon of the image is known and compass points and tilt angles will be shown automatically if set to be shown.

  2. Similarly, if you save a view of an image that has its North point and/or horizon set, that saved view will include known geographic settings; see the Saving views page for more details.

  3. In the starter image you’ll see a white electricity pylon close to the −90 point if you pitch down far enough; the base of the pylon is close to True North from the drone position.

Here is a view showing the Compass points, Tilt angles, and Grid overlays:
PanGazer screenshot showing grid and other overlays

PanGazer screenshot showing grid and other overlays

PanGazer and these web pages were written by Mike Cowlishaw; Please send me any corrections, suggestions, etc.
All content Copyright © Mike Cowlishaw, 2014–2022, 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 2022-09-01 by mfc.