GPS metadata -- error ranges?

[wsherman]

Hello,

Just learned about the exiftool recently, and as I've been keeping GPS datalogs of late in order to post-facto GPS tag my images, I'm sure it will be a highly used tool (when I get around to doing the tagging).

Related to that, I hope to one day attempt to Geotag as many of my digital photos from before I acquired a GPS datalogger (and some after I got the logger, but lost some logged data, or didn't have the logger running for various reasons).  So when I attempt this, I'll be more or less guessing at the GPS coordinates for many of these pictures, and I predict that sometimes I'll be more confident of my location than other times -- in particular, I'm predicting I could be off by several miles when it comes to pictures taken out the window of an airliner.

So I'm hoping (though not particularly optimistic, since my perusing of EXIF tag lists hasn't suggested an obvious answer), that there are, or perhaps could be in the future, EXIF tags that would provide a confidence interval or range for given Geo tag values.  Something that suggests I'm within 10 feet, 500 feet, 1 mile, or 50 miles of where the photo was taken.

Are other people clamouring for this sort of tag?  Or am I a lone wolf?

    Thanks,
    Bill

[Phil Harvey]

Hi Bill,

The EXIF GPS specification provides a "Dilutation of Precision" tag which is related to the accuracy of the measurement.  You could possibly use this tag, although it exactly what you wanted because it isn't a simple measurement.  You would have to do some research to figure out how to relate this number to a distance error.

- Phil

[Phil Harvey]

Good news:

A new EXIF specification has just been released which adds a GPSHPositioningError tag.

ExifTool 8.20 will support the new EXIF 2.3 specification.

- Phil