GPS-fields and its meaning

[sinus]

Hi all
Since GPS is here in the forum a theme and because GPS will be more important than it was, I checked the exif-fields in an image of me with the browser of IMatch.

In my attachement you will see these fields. I understand some of them, but the fields with the red rectangle at I do not know, what they are.
Has someone e.g. an idea, what GPS-speed means?

And this cam, I think, is missing the "direction-field", what theme is here lately in the forum mentioned.

Not an important question, only good to know.

[axel.hennig]

Hi sinus,

from http://www.exif.org/Exif2-2.PDF I got the following information:

- GPS Differential: Indicates whether differential correction is applied to the GPS receiver.
- GPS Dilution Of...: ?
- GPS Map Datum: Indicates the geodetic survey data used by the GPS receiver. If the survey data is restricted to Japan, the value of this tag is 'TOKYO' or 'WGS-84'. If a GPS Info tag is recorded, it is strongly recommended that this tag be recorded.
- GPS Measure Mode: Indicates the GPS measurement mode. '2' means two-dimensional measurement and '3' means three-dimensional measurement is in progress.
- GPS Speed: Indicates the speed of GPS receiver movement.
- GPS Speed Ref: Indicates the unit used to express the GPS receiver speed of movement. 'K' 'M' and 'N' represents kilometers per hour, miles per hour, and knots.
- GPS Status: Indicates the status of the GPS receiver when the image is recorded. 'A' means measurement is in progress, and 'V' means the measurement is Interoperability.
- GPS Time Stamp: Indicates the time as UTC (Coordinated Universal Time). TimeStamp is expressed as three RATIONAL values giving the hour, minute, and second.
- GPS Track: Indicates the direction of GPS receiver movement. The range of values is from 0.00 to 359.99.
- GPS Track Ref: Indicates the reference for giving the direction of GPS receiver movement. 'T' denotes true direction and 'M' is magnetic direction.

Hope this helps a little bit.

[axel.hennig]

... and perhaps GPS Dilution Of... can be (see https://en.wikipedia.org/wiki/Dilution_of_precision_(navigation)):

- Dilution of precision: A term used in satellite navigation and geomatics engineering to specify the additional multiplicative effect of navigation satellite geometry on positional measurement precision.

[sinus]

Hey Axel,

thanks a lot!
I think, you have covered and solved all, what I wanted to know.
And with your link I have also to look up more, if I want. 

Thank you!