Author Topic: Should Destination (Location Shown) Tags be added?  (Read 1682 times)

Tveloso

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Should Destination (Location Shown) Tags be added?
« on: November 23, 2019, 04:56:48 AM »
I have noticed that when the Location Tags are populated when either Reverse GeoCoding, or applying an IMath Location, that the corresponding Destination Tags are also populated.

That is, when these Tags:

Code: [Select]
[XMP-exif]          - GPS Latitude
[XMP-exif]          - GPS Longitude
[XMP-exif]          - GPS Altitude
[XMP-iptcCore]      - Country Code
[XMP-photoshop]     - Country
[XMP-photoshop]     - State
[XMP-photoshop]     - City
[XMP-iptcCore]      - Location

...are added to, or updated in a file, via one of those two operations, theses Tags:

Code: [Select]
[XMP-iptcExt]       - Location Shown GPS Latitude
[XMP-iptcExt]       - Location Shown GPS Longitude
[XMP-iptcExt]       - Location Shown GPS Altitude
[XMP-iptcExt]       - Location Shown Country Code
[XMP-iptcExt]       - Location Shown Country Name
[XMP-iptcExt]       - Location Shown Province State
[XMP-iptcExt]       - Location Shown City
[XMP-iptcExt]       - Location Shown Sublocation

...are then also added to the file.

I have been wondering whether it's actually appropriate to have Location Shown GPS Coordinates added to a File that previously contained only the "camera standpoint" GPS Coordinates.  There have been a number of topics in the community that have touched upon my questions in this area.

Although one topic dealt specifically with questions on GPS Altitude when Reverse GeoCoding and/or applying an IMath Location, a part of one posting there:

1. Location added in Map window: ECP output...
2. Location added in Map window, reverse geocoded: ECP output shows...
3. Location added in Map window, added destination shown, reverse geocoded: ECP output shows...

...could suggest that the destination shown data might be able to be "switched off", and optionally added by the user when needed.  I looked around for such a configuration option, but didn't find one.

Then I thought that perhaps having both sets of Location Data populated might be part of MWG compliance...but it would make sense to me to have only the "camera standpoint" Location Tags populated most times, and to have the corresponding Location Shown Tags also exist in an image, only when the "camera standpoint" GPS coordinates, and Location Shown GPS coordinates, are far enough apart to warrant it.   

In either case though, I think that I may have found a slight bug in setting the Shown GPS coordinates, when an IMatch Location has been applied via a Metadata Template.

When a Metadata Template is applied, that includes the Location option in Automatic Mode, with the Assign GPS coordinates of location option unchecked, and the resolved-to location having its Snap image coordinates to location coordinates option unchecked, the original GPS Coordinates in the image are retained as expected, but the Location Shown GPS Coordinates are set per the location's Center Point.  In an image whose GPS coordinates correspond to the very edge of the resolved-to location, this can result in the appearance that the photo was taken far from the subject (when in fact the subject was actually at the camera standpoint).  And this goes back to the question of whether or not it's appropriate to add the Location Show Tags to a file that didn't previously have them...

This also touches upon another community topic:

https://www.photools.com/community/index.php?topic=9306.msg65556

...and I'll post a reply there, with my question on that subject.
--Tony

Mario

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Re: Should Destination (Location Shown) Tags be added?
« Reply #1 on: November 23, 2019, 07:51:05 AM »
I don't recall the exact rules anymore currently. But what to fill when and under which conditions is covered in the XMP spec and the MWG rules.
And it was much discussed when I've added reverse geocoding and later the support for location created / location shown.
When I recall correctly, what the reverse geocoding does and what the map panel does when there is only created or shown or both is correct.

Tveloso

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Re: Should Destination (Location Shown) Tags be added?
« Reply #2 on: November 23, 2019, 01:30:09 PM »
Thank you Mario.  I thought that might be the case (that the creation of the Location Shown Tags is a requirement).

But I still wonder if the specific case of creating them from an IMatch Location, via a MD Template at ingest, might involve a bit of a bug, because the Shown coordinates are being populated from the Location's Center point, rather than from the coordinates that the image originally contained.

If we consider only the GPS coordinates from both sets of Location Tags...lets say we have an image that contains only these Tags (the ref Tags are omitted for the sake of illustration):

Code: [Select]
[Composite]         - GPS Latitude
[Composite]         - GPS Longitude
[GPS]               2 GPS Latitude
[GPS]               4 GPS Longitude

After being indexed (during which an IMatch Location has been applied), the image now has these tags:

Code: [Select]
[Composite]         - GPS Latitude
[Composite]         - GPS Longitude
[GPS]               2 GPS Latitude
[GPS]               4 GPS Longitude
[XMP-iptcExt]       - Location Shown GPS Latitude
[XMP-iptcExt]       - Location Shown GPS Longitude

...but the Shown Lat and Long are different from what was originally in the image (they are taken from the Location's Center Point).  So we wind up with an image where the two coordinate sets may be quite different (making it appear that the Camera Standpoint, and the Subject of the image were far apart, when in fact they were actually at the same spot.
--Tony

Mario

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Re: Should Destination (Location Shown) Tags be added?
« Reply #3 on: November 23, 2019, 01:33:43 PM »
You use a MD template which which settings to set the coordinates?

As far as I can see, the coordinates of the file are only modified if the "snap to" option is enabled in the MD panel or if the location itelf has this option enabled.
« Last Edit: November 23, 2019, 02:01:50 PM by Mario »

Tveloso

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Re: Should Destination (Location Shown) Tags be added?
« Reply #4 on: November 23, 2019, 02:01:59 PM »
The MD Template has the location set for Automatic, with the Assign GPS coordinates of location option unchecked:



And the Location has its Snap image coordinates to location coordinates option unchecked.  That Template is selected for new files under Apply Metadata Templates, in Edit>Preferences>Indexing.
--Tony

Mario

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Re: Should Destination (Location Shown) Tags be added?
« Reply #5 on: November 23, 2019, 02:03:08 PM »
I will move this to the bug report board. I will check this for one of the next releases.

Tveloso

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Re: Should Destination (Location Shown) Tags be added?
« Reply #6 on: November 24, 2019, 04:43:14 PM »
Thank you Mario.

Discussions in another topic prompted me to just add this additional note here...(for when you a are able to get back to this).

Despite the Title of this topic, it's not really the question of whether or not the Location Shown tags should be added, but that when they are added (via the application of an IMatch Location by a Metadata Template), the Shown coordinates are set per the location's Center Point (which can make it appear that the Camera Standpoint and Subject were far apart). 

I would expect that when the Shown coordinates are added, they would be the same as the Created coordinates (that's what happens with Reverse GeoCoding).

Thank you so much.
--Tony