Needing 2 or 3 Write-Backs - GPS Data Changes by ExifTool?

[PandDLong]

I have updated a few hundred photos with various metadata changes and decided I was finished and was doing write-backs (I typically do them in batches).  These files hadn't had a write-back for many months (or even a year or two).   The changes were not geo-related (GPS / Map / Location tags).  

When I do the Write-Back, after reading the Metadata back into iMatch, the Pending Write-Back pen is back on for 80-100% of the files.   It is showing that the following tags from the XMP::exif group need to be updated:

   GPSDestDistance
   GPSDestDistanceRef
   GPSImgDirection
   GPSImgDirectionRef           

(Note that some only had the first 3 tags to write back and not the 4th - I could not see a pattern of why).

After I completed another Write-back for these, a handful are needing a third write-back because of:

   GPSImgDirection


Perhaps I missed something in the release notes, is this related to a recent update to Exiftool or iMatch?  

Should I expect this to be a one-time event for each file as they get written-back in order to correct/synchronize some data?  
Or should I start double-checking my write-backs to repeat the process to get to a "No Pending Update" state?


Michael

[Mario]

Maybe related to release note #02391 and #02317?
You can use the search function on the release notes page to find them (enable search all products).

[PandDLong]

Yes, that was it.   

Looks like there had been some rounding of GPS at some point as exiftool comes back with a very small fractional distance between the GPS and GPSDestination tags so then it updates the distance, direction, etc.

Thanks for the recall on which release note it was.

Michael

[PandDLong]

I checked and practically of my files have a difference between the GPS co-ordinates and the GPS Destination co-ordinates of 0.000001 or less.  In my case I do sometimes use Destination co-ordinates purposefully but probably less than 1 in a 100 (and much more than a few metres of difference).

Looks like I need to apply a metadata template to align them to be the same so this issue will be dealt with and won't resurface constantly whenever I touch an older photo.


I note that in my iMatch Locations the Lat/Long co-ordinates have 6 decimal places -  is that the amount of precision iMatch uses in general and/or is recommended?

Michael

[Mario]

IMatch does not set these coordinates. They are delivered by ExifTool. Unless you change them in IMatch (Map Panel, MD Panel).