Samples of GPS

[evilaro]

Hello:

I am working with the GPS latitude longitude tags.

In my application, the format I use is a bit different form what it comes
from the Exif, so I have to modify it.

Since I do not have samples of ALL West-East  North-South Coordinates,
after doing the changes I am not sure if that will work for all the
4 corners of the world plus the fact that degrees can be 1,2 or 3 numbers
and the same can happen with minutes and seconds.

So :

a) The exif format for the coordenates is equal ALL OVER?

b) Where could I get the exact format that for this coordinates (explaining the 1,2,3 number position)

c) Is there a way to get some image samples with this coordenates
   or as another possibility only valid EXIFs

d) the tag GPS Longitude/latitude   comes with two different possibilities
   GPS Longitude                   : 135 deg 46' 29.56"
   GPS Longitude                   : 135 deg 46' 29.56" E
   with and without The W-E
   Is there a way to avoid it.

e) I could try to use a image and put the test coordenates into it...

  IF

  I do that... regardless of the format I introduce (a valid format)
  will the result placed on the exif will be unique? and equal to .. for example
 a coordenate taken with a camera, or it could be several similar format.

....
I hope muy questions are clear... sorry for the cuantity

Emilio



   

[Phil Harvey]

Hi Emilio,

The EXIF GPSLatitude and GPSLongitude tags do not contain N/S or E/W information, but the XMP ones do.  For EXIF you must also write GPSLatitudeRef and GPSLongitudeRef.  Use -G1 -a to extract all values and see where they came from.  ExifTool also creates a Composite value from the related EXIF tags to make things easier for copying to XMP.

Internally, EXIF stores coordinates as 3 rational values.  ExifTool handles this for you and allows you to use many different formats.  Use the -v option when reading to see exactly what was written.

- Phil

[mvadu]

From Exif Spec:
GPS expressed as three RATIONAL values giving the degrees, minutes, and
seconds, respectively. If latitude is expressed as degrees, minutes and seconds, a typical format would be
dd/1,mm/1,ss/1. When degrees and minutes are used and, for example, fractions of minutes are given up to two
decimal places, the format would be dd/1,mmmm/100,0/1.

To get E/W and S/N information you need to refer GPSLongitudeRef and GPSLatitudeRef respectively.

(Not that I am answering your question, just adding to Phil's answer)

[evilaro]

Hi Phil:

Thanks ... that makes my work simpler and more understandable.

Emilio

Hi Emilio,

The EXIF GPSLatitude and GPSLongitude tags do not contain N/S or E/W information, but the XMP ones do.  For EXIF you must also write GPSLatitudeRef and GPSLongitudeRef.  Use -G1 -a to extract all values and see where they came from.  ExifTool also creates a Composite value from the related EXIF tags to make things easier for copying to XMP.

Internally, EXIF stores coordinates as 3 rational values.  ExifTool handles this for you and allows you to use many different formats.  Use the -v option when reading to see exactly what was written.

- Phil

[evilaro]

mvadu:

Thanks... for the clarifications.... there are so many options
that it was difficult to see the correct way.

With this it is more easy.

Emilio

From Exif Spec:
GPS expressed as three RATIONAL values giving the degrees, minutes, and
seconds, respectively. If latitude is expressed as degrees, minutes and seconds, a typical format would be
dd/1,mm/1,ss/1. When degrees and minutes are used and, for example, fractions of minutes are given up to two
decimal places, the format would be dd/1,mmmm/100,0/1.

To get E/W and S/N information you need to refer GPSLongitudeRef and GPSLatitudeRef respectively.

(Not that I am answering your question, just adding to Phil's answer)

[Phil Harvey]

Just to reiterate my point:  It doesn't matter how you write the coordinates.  ExifTool will reformat them appropriately and convert them to the 3 rational values stored in the EXIF.

- Phil