How to make Field of View visible in IMatch map

[Jim K.]

Hi,

the map in my IMatch does show the correct GPS position in the map (see 1), but does not show the Field of View.
The file does cointain GPS image direction (see 6), but this information is not visible in IMatch metadata (see 4). For IMatch settings see 2 and 3.

Is there something wrong in the settings to make FoV visible?

Jim

P.S.: photos were taken with Apple iPhone 15 Pro, jpeg

[mopperle]

As I understood, you need a "destination GPS coordinate" to get the direction and the FOV being displayed:
https://www.photools.com/help/imatch/panel_geo.htm?dl=hid-13
No idea why IMatch doesnt use the direction provided by the exif data.

[Mario]

No idea why IMatch doesnt use the direction provided by the exif data.

This is how I've implemented this back in IMatch 2016. Nobody ever asked for support of image direction reference before, and this has only become a topic at all since some smart phones add this particular tag.

According to telemetry, over 80% of the IMatch user base does not even show field of view in the Map Panel and the IMatch camera database has hundreds of smart phone models with unknown sensor size (which is required to calculate the actual FOV).

There is no related feature request AFAIK and it would be interesting to see how many users would actually need this.
As always, if a feature is useful for a substantial number of users, I will look into implementing it.

(see 6), but this information is not visible in IMatch metadata (see 4).

Just add the corresponding tag to the Metadata Panel layout. The default layouts show only tags relevant for most users, not every available GPS tag. You can see it when you switch to the "Browser" layout.

See Metadata Panel Layouts to learn how to add more tags to an existing layout and how to create your own custom layouts.

[Jim K.]

Hi Mario,

actually I did added the tag, but it is empty in IMatch (see attachnemt). Wrong tag?

Jim

[mopperle]

According to telemetry, over 80% of the IMatch user base does not even show field of view in the Map Panel

Not sure how you measure this. In the Map Configuration I've set to display Fov for the focused file (default setting I assume). But I think as you need 2 pairs of coordinates and most users will not put so much effort into it to enter a 2nd GPS coordinate, no FOV is shown.
But you are right, mostly smartphone write the directon tag into the Exifs. But most DSLR supply no direction or do not have GPS at all (e.g. my Canon 6DMII got GPS but no diection, my EOS R no GPS at all). Dont ask me why the manufactureres dediceded to do so.
On the other hand since I have my iPhone 13Pro, the number of pictures I take with the smartphone have "exploded". Especially when I'm out in the mountains. It is not funny to carry "additional camera load" with you.
So why not draw a direction arrow on the map, when the data are available? The FOV is mostly just good guessing and not as usefull as having the pure direction. The advantage would be that you would not have to support a database with thousands of lenses and formats.

[Jim K.]

I would agree to mopperle. To show in the map just the direction (taken from Exif without any additionl data or calculation) would be good enough.

[mopperle]

Hi Mario,

actually I did added the tag, but it is empty in IMatch (see attachnemt). Wrong tag?

Jim

Did the same, but it doesnt seem to work. Added "GPSImgDirectionRef", choose "true north" add a value, e.g. 270 under "GPSImgDirection ", but when writing back fields are cleared.

[Mario]

Which tag did you use? The XMP tag? Or the native GPS tag? IMatch maps XMP2GPS on write-back.

The FOV funnel is controlled by sensor size, or assumed to be full-frame if sensor size is not available.
IMatch currently only calculates image direction in the Map panel when there is a target marker, it does currently not use the direction tag.

As per usual, a feature request will tell us if and how many users would like such a feature. Feel free to add one.

[mopperle]

Which tag did you use? The XMP tag? Or the native GPS tag? IMatch maps XMP2GPS on write-back.

I used these tags


But I'm confused about this message:


When I enter something in the field XMP exif\GPS Image Direction and write it back, the field will be cleared, but the content overwrites the Value GPS\GPSImgDirection

[Mario]

Dos the file have only one coordinate (lat/lon)? Probably IMatch wipes the direction during write-back when it has only one coordinate and is hence assumed to have only a point but no direction.

[mopperle]

I noticed something very strange when lookng back to older pictures:
All (iPhone) pictures up to 31.12.2023 show this in the metadata:


From the 01.01.2024 for all pictures 2 lines are empty. Same camera, same iOS, same software, no difference in GPS Data:


Any idea? If needed I can attach the original files (RAW and jpg).

[Mario]

Is the data in the file? Did you check with ExifTool Command Processor?

[mopperle]

Yes, see attched results. Interesting that the data also contain the FOV.

[Jim K.]

By now I did not really used GPS data productive. Regarding to mopperle's post today 10:26 I have checked my photos.

I had GPS switched on 13.10.2023 and photo and IMatch shows data for direction and image direction unit (bur does not show in map).

Next time I had GPS switched on, was at 27.11.2023: both data are in file, but not shown in IMatch.
From that point of time both data did not show up in IMatch anymore.

All photos done with iPhone 15 pro.
 

[Mario]

The FOV appears in some virtual Composite tag ExifTool makes up on-the-fly.
The image contains the ImgDir in the XMP and native GPS, it should show in the MD Panel Browser.
Send me a sample image to support email address (with a link back to this topic. I'm still working on emails received last Thursday, it's mad).

[mopperle]

Send me a sample image

Done

[Mario]

Send me a sample image

Done

Thanks for sending the files. When I import them into IMatch, I see these values for the two sets of files (the DNG and JPG pairs have the same coordinates):



I wonder what the difference is. I've used IMatch 2025 for my test (IMatch 2023 is code freeze and I have no instance running at the moment).

I did some changes to how XMP GPS is processed, dealing with GPS import with and without shown/created coordinates and some 'issues' found in some action camera data. Maybe I have "fixed" something? I don't really know.

Anything special you did with these files in your database? Map Panel? Reverse geocoding? IMatch Location applied? Metadata Template applied which modifies coordinates?

I've made copies of all four files and moved the file markers in the map panel a bit.
Then I wrote back. The new coordinates were written correctly and the image direction was not changed by this operation. Not sure what else to try.

[mopperle]

Anything special you did with these files in your database? Map Panel? Reverse geocoding? IMatch Location applied? Metadata Template applied which modifies coordinates?

No, did nothing special at all. Strange that it started from January 2024. Was there an update in Imatch at that time?

What I will try later: remove the picture from 2023 from the IMatch DB, move the file to another physical folder (via Windows explorer), import that folder into Imatch and then move (within IMatch) the file to its original folder.

[Mario]

I've looked at the revision history for IMatch 2025 (several thousand changes over IMatch 2023) and I found one comment that the XMP::exif:imgDirection tag may have been marked as "delete" when GPS coordinates were set in the database and there was no destination coordinate or only a destination coordinate but no created coordinate.

This was under the assumption that having only one coordinate does not allow for an image direction. If cameras write an image direction tag but only one coordinate pair (why?) this would probably/maybe explain this? I have revisited this code section a while ago in the IMatch 2025 code base, removing the "two coordinate pairs" condition and now IMatch deletes image direction only when there are no GPS coordinates (anymore) in the image.

Of course as soon as you add a target marker, the image direction is calculated from the two coordinate pairs and two sets of location data are maintained (shown / created).

[mopperle]

If cameras write an image direction tag but only one coordinate pair (why?

What other pair should a camera write? The camera does not know what I'm aiming at. The person in front of a bridge or the church behind the bridge, the building 200 m away or the mountain 20 km away? The camera doesnt know anything about the content of the picture, for the camera a picture is nothing more then millions of "1" and "0". And  the combination of one set of GPS coordinates and the direction simply tells that at the time the picture was taken, camera stands at this position and looking in that direction.

I can give you an example, why having this one pair of ccordinates and the direction in the metadata and in the map would be helpfull: some years ago I crossed the alps in a hotair balloon, taking many pictures from about 16.000 to 18.000 feet ASL in various directions. At that time I had no camera giving me any GPS data. As mountains from such a flightlevel look totally different than from the ground, having the position and direction could have helped me to determine which mountain(area) I was making pictures of.

[Mario]

What other pair should a camera write? The camera does not know what I'm aiming at.

The camera knows the direction (apparently). And it has sensor information for point of focus (aka distance to the object you were focusing on). Might be difficult when you take a photo of a mountain 5 kilometers away, but when you focus on a person or object, that's the coordinate shown, I think?

I will have a look at the feature request to show some sort of arrow to indicate the ImgDirection when available, even if there is only one pair of coordinates. Since there is no target, the arrow would just have a certain length and visualize the direction recorded by the device.

[mopperle]

Since there is no target, the arrow would just have a certain length and visualize the direction recorded by the device.

Much appreciated!

[Jim K.]

Thank you for your effort.

Jim

[loweskid]

A few years ago I had a GPS gadget called Easytagger which recorded both direction and field of view.  I've attached a screenshot of how it displays in Geosetter (which also uses Exiftool).  Also displayed are the GPS cordinates.  Notice that the Field of View tag (14.4deg) is not included in the 'Location' group but is listed just above, which comes under the 'Image' group heading.

[Mario]

This is exactly what you get in the Map Panel when you add a target coordinate.
Displaying the Field of View (FOV)

It seems that this file has also a target coordinate? Or what is the second dot at the bottom right?
See also the corresponding and already implemented feature request here: https://www.photools.com/community/index.php/topic,14636.0.html

[loweskid]

It seems that this file has also a target coordinate? Or what is the second dot at the bottom right?

I'm not sure what you mean by bottom right.  If you mean bottom left it's irrelevent - it's just where I happened to click on the map just before taking the screen shot.  I don't recall adding any target coordinate, all the information displayed came from the Easytagger unit.

The direction and field of view cone display moves and keeps expanding if I scroll the map to the right. 

[Mario]

I meant top right, sorry. Bottom left is a pin and at the top-right is a circle. IMatch also uses a circle to indicate the target (location shown). With both coordinates and the senor diagonal, the field of view can be accurately calculated and shown in the Map Panel.

FieldOfView is not part of EXIF or GPS. Some GoPros write a tag with that name, same for pro FLIR thermal cameras. That's about it. DICOM (medial scanners and cameras) records several field of view tags. Sometimes in QuickTime, too.

GPS gadget called Easytagger which recorded both direction and field of view.

How did it do that and where did it record that? Your screen shot does not show the tag names. Maybe the Composite tag ExifTool calculates on-the-fly from various tags or something GeoSetter did?

[loweskid]

How did it do that and where did it record that? Your screen shot does not show the tag names. Maybe the Composite tag ExifTool calculates on-the-fly from various tags or something GeoSetter did?

I think you are correct about it being a composite tag but this appears to already exist in exiftool.  On the exiftool forum I found this ....

https://exiftool.org/forum/index.php?topic=11574.0

which has a link to a list of exiftool's Composite Tags where FOV is listed....

https://exiftool.org/TagNames/Composite.html

edit - " Composite FOV is computed from FocalLength, ScaleFactor35efl, and FocusDistance"

[mopperle]

Thats correct the FOV and all other GPS data are written to composite tags and based on this Geosetter displays the viewing direction:

[Mario]

I know about the Composite tag.
In don't understand the purpose of your post. IMatch handles image direction, IMatch shows a FOV overlay when there is a created and destination coordinate (created and shown).

What do you suppose in addition?
In your screen shot there are two points and a FOV funnel. This is exactly what IMatch also shows.
IMatch 2025 now also visualizes the image direction when available.

Do you propose that IMatch should use the FOV ExifTool calculates and the image direction and then somehow project a FOV funnel even when there is no target marker? Assuming some "distance" to limit the size of the funnel?

The original poster of this thread made a separate feature request and I decided to implement it. https://www.photools.com/community/index.php/topic,14636.0.html already.

[loweskid]

Do you propose that IMatch should use the FOV ExifTool calculates and the image direction and then somehow project a FOV funnel even when there is no target marker? Assuming some "distance" to limit the size of the funnel?

That's the point really!  Suppose I have a photo taken in the Scottish mountains and want to identify a distant peak.  IMatch will show my location but if I don't know the direction in which the camera was pointing, or the distance to the peak, how can I add a target marker?  Geosetter shows the direction and FOV without the need of a target and from that I can (usually) identify the peak.

[Mario]

If you have only a point and a direction, the FOV would be infinite. Not sure if this helps many.

Feel free to add a feature request so we can see how many users would like to have that.

[loweskid]

If you have only a point and a direction, the FOV would be infinite. Not sure if this helps many.

Feel free to add a feature request so we can see how many users would like to have that.

On the image that I posted, if I scroll the map and follow the direction, it terminates about half way across the North Sea.  Not infinity but probably about as much help...

I'll leave it to the original poster to decide if he wants to make a feature request.  To be honest I stopped using the Easytagger a while ago.  It was a pain to use; every time it was switched on you had to rotate it 360 deg to calibrate the compass then keep it horizonal all the time it was in use.  If it lost the GPS signal you had to go through it all again.  Then the battery packed in so I binned it. 

I'm now using a gadget called Unleashed which gets it's GPS data from my phone but it doesn't give FOV.  But maybe sometime in the future....