Re: Can you help me interpret GPS EXIF data embedded in digital photos?

Simone D.

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Oct 10, 2012, 12:20:02 PM10/10/12

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On Wed, 10 Oct 2012 16:41:23 +0100, David Taylor wrote:

> How are you viewing the EXIF data?

I'm using Linux "Eye of GNOME" version 2.30.0, File->Properties.

The funny thing is there is no Latitude either.
Is this normal from an iPhone photo?

Simone D.

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Oct 10, 2012, 12:22:32 PM10/10/12

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On Wed, 10 Oct 2012 08:52:26 -0700, Savageduck wrote:

> On 2012-10-10 07:16:05 -0700, "Simone D." <simone...@ymail.com>
> said:
>
>> Can you help me interpret GPS EXIF data embedded in digital photos?
>>
>> I would have expected iPhone or Android phones to save both longitude
>> and latitude information - but the EXIF data doesn't seem to be that.
>>
>> For example, the Golden Gate Bridge is at the GPS coordinates: a)
>> Decimal Minutes (GPS) : N37 49.19819 W122 28.71539 b) Decimal (WGS84) :
>> 37.81997, -122.47859 c) Degrees Minutes Seconds : N 37° 49' 11.8914", W
>> 122° 28' 42.9234"
>>
>> But, none of these seem to align with the coordinates in the EXIF data:
>> GPSLongitudeRef = E
>> GPSLongitude = 51.00, 27.76, 0.00
>> GPSAltitudeRef = Sea Level
>> GPSAltituide = 24.00
>> GPSTimeStamp = 12:31:03:97
>> GPSImgDirectionRef = T
>> GPSImgDirection = 69.05
>
> Your assumption that both longitude & latitude should be saved is
> correct, and the exif data should reflect that.
>
> In the example you have given us you seem to have bad data, or at least
> one or more tracking errors. I believe it would be fair to assume the
> "E" in the Long. data represents "Error". Then the Lat. data just does
> not make sense for the Golden Gate Bridge.
>
> The GP-1 unit on my D300S gives the following data for a shot taken on
> the bridge:
>
> 37°49'12" N 122°28'43" W
> Alt: 185 ft.
>
> As far as interpreting the data goes, your available software is going
> to play a part.
> I am using a Mac and as a simple viewer I use Apple's Preview, that will
> show the GPS data and when clicking on the locate button, will open
> Google Maps and indicate with the "green arrow" my position for the
> shot. So below is a screen capture of the shot including the data
> window, and how that is presented on Google Maps. <
> https://dl.dropbox.com/u/1295663/FileChute/screenshot_31.jpg > <
> https://dl.dropbox.com/u/1295663/FileChute/screenshot_32w.jpg >
>
> Then I also use Lightroom 4 which gives me the ability to map imbedded
> GPS data, or to place untagged images on the map to add GPS data to the
> EXIF. That gives me locations for a particular shoot. <
> https://dl.dropbox.com/u/1295663/FileChute/screenshot_30w.jpg >
I'm using Eye of Gnome on Linux.

I guess that's why the latitude doesn't show up in the iPhone photo
even though the longitude shows up but in a funny way?

Does anyone out there have GPS enabled on their iPhone to show what
it looks like on Linux?

Savageduck

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Oct 10, 2012, 12:45:59 PM10/10/12

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I can't speak for Linux iPhone users, but I ask, is this an issue with
all your GPS enabled iPhone photos, or just the GGB shot?

Then there is the issue of obtaining a solid satellite fix vs a cell
tower triangulation, and a satellite+cell tower fix. Also to be
considered would be cell towers covering the GGB area, their ability to
triangulate, and the 3G/4G reception around the bridge. The thing to
remember is the iPhone is not a dedicated GPS unit, and it is quite
possible that there was interference created by the bridge structure
corrupting both satellite & cell tower fixes.

--
Regards,

Savageduck

ray

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Oct 10, 2012, 1:25:57 PM10/10/12

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Try exiv2, exif or exiftool

Simone D.

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Oct 10, 2012, 3:00:12 PM10/10/12

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On Wed, 10 Oct 2012 09:45:59 -0700, Savageduck wrote:

> I can't speak for Linux iPhone users, but I ask, is this an issue with
> all your GPS enabled iPhone photos, or just the GGB shot?

I will check.

If someone else has an iPhone, can they just report what they see on
Linux default Eye of Gnome for the GPS settings?

For example, where is latitude?

Alan Browne

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Oct 10, 2012, 5:10:28 PM10/10/12

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The EXIF data in an iPhone (see my prior post) has the information in
two areas of the output (from exiftool). You may have missed the actual
data.

As I said in my other post submit your photo to this site:
http://regex.info/exif.cgi and see how it analyzes it.
it will also geolocate the image for you.
(I have no affiliation with that site).

--
"There were, unfortunately, no great principles on which parties
were divided – politics became a mere struggle for office."
-Sir John A. Macdonald

do...@91.usenet.us.com

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Oct 14, 2012, 1:24:03 PM10/14/12

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In alt.satellite.gps.garmin Simone D. <simone...@ymail.com> wrote:
> If someone else has an iPhone, can they just report what they see on
> Linux default Eye of Gnome for the GPS settings?

If you post photos to Picasaweb, there is a "full details" option to the
right that will show GPS details, as a check as to whether this is an issue
with your photos or the Linux App.

I just looked at a photo on Picassa, then downloaded to Ubuntu, where the
default image viewer shows no GPS details. Looking at the original from
the Android photo with the default image viewer shows the GPS details, and
using the default command line
identify -verbose picture.jpg |grep GPS
exif:GPSDateStamp: 2012:10:06
exif:GPSInfo: 1434
exif:GPSLatitude: 38/1, 45/1, 21/1
exif:GPSLatitudeRef: N
exif:GPSLongitude: 122/1, 36/1, 47/1
exif:GPSLongitudeRef: W
exif:GPSProcessingMethod: ASCII
exif:GPSTimeStamp: 8/1, 24/1, 53/1

--
Clarence A Dold - Hidden Valley Lake, CA, USA GPS: 38.8,-122.5