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

Discussion in 'Digital Photography' started by Simone D., Oct 10, 2012.

  1. Simone D.

    Simone D. Guest

    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
    Simone D., Oct 10, 2012
    #1
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  2. Simone D.

    Johannes Guest

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

    Maybe the GPS guys know the answer?

    On Wed, 10 Oct 2012 14:16:05 +0000, Simone D. wrote:

    > 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
    Johannes, Oct 10, 2012
    #2
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  3. Simone D.

    David Taylor Guest

    On 10/10/2012 15:16, Simone D. wrote:
    > 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


    Both my iPad3, Sony HX200V camera, and Huawei Ascend G300 phone save the
    EXIF GPS data exactly as I would expect. How are you viewing the EXIF
    data. I use GeoSetter, or PIE Studio, or the EXIF Viewer add-on for
    Firefox. Can you put that image online so that we can check that EXIF
    data with different programs?

    One caveat is that immediately after switching on the GPS will not have
    acquired a signal lock, and there should be /no/ GPS data recorded.
    After some time, there will be less accurate data, and then within a few
    metres. One other possibility is that the device is using Wi-Fi
    location data instead of GPS data, and that location data is wrong.

    Perhaps the device is remembering its last-used location?
    --
    Cheers,
    David
    Web: http://www.satsignal.eu
    David Taylor, Oct 10, 2012
    #3
  4. Simone D.

    Simone D. Guest

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

    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., Oct 10, 2012
    #4
  5. Simone D.

    Simone D. Guest

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

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

    > On 2012-10-10 07:16:05 -0700, "Simone D." <>
    > 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?
    Simone D., Oct 10, 2012
    #5
  6. Simone D.

    ray Guest

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

    On Wed, 10 Oct 2012 16:22:32 +0000, Simone D. wrote:

    > On Wed, 10 Oct 2012 08:52:26 -0700, Savageduck wrote:
    >
    >> On 2012-10-10 07:16:05 -0700, "Simone D." <>
    >> 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?


    Try exiv2, exif or exiftool
    ray, Oct 10, 2012
    #6
  7. Simone D.

    Simone D. Guest

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

    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?
    Simone D., Oct 10, 2012
    #7
  8. Simone D.

    Guest

    In alt.satellite.gps.garmin Johannes <> wrote:
    > Maybe the GPS guys know the answer?


    Depending upon the options set, the camera app probably starts with no
    position fix, then gains a cellular fix, which is inaccurate by tens of
    miles in some cases, them gains a satellite lock, which might take a while
    in a car, both because it is moving and because of shielding away most of
    the sky view of the GPS satellites. In an urban canyon like downtown SF,
    or maybe the passing bridge cables, a proper GPS lock might never be
    obtained.

    If you were looking at a GPS screen, you might patiently wait for the fix
    to become accurate. Pressing the trigger on the camera takes the picture,
    and accepts the current state of the GPS fix. That might include the
    moments when portions of the GPS information are filled in, and some are
    missing.

    I have looked at the GPS fixes on Blackberry and Android and I find missing
    GPS, and good GPS, with some cellualr-only fixes, but I don't recall seeing
    data as bad as the original poster's.

    --
    Clarence A Dold - Hidden Valley Lake, CA, USA GPS: 38.8,-122.5
    , Oct 14, 2012
    #8
  9. Simone D.

    Guest

    In alt.satellite.gps.garmin Simone D. <> 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
    , Oct 14, 2012
    #9
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