Monday, September 20, 2010

Beware of Geotagging

Geotagging is the process of adding geographical identification metadata to various media such as photographs, video, websites, or RSS feeds and is a form of geospatial metadata. These data usually consist of latitude and longitude coordinates, though they can also include altitude, bearing, distance, accuracy data, and place names. It is commonly used for photographs, giving geotagged photographs.

Source: Wikipedia, http://en.wikipedia.org/wiki/Geotagging


In digital photography, basically it sticks GPS coordinates to your photo.  Long time ago (during 35mm era) if you do not want to forget the date of the photo taken, you can opt to enable it on the camera to 'print' it onto the photo itself.  Every time you print on those photo paper, the date appears at the bottom (can't recall whether on the left of the right corner).  I hate this features as it spoilt the photo.

In the digital era, the date is captured in EXIF data among other information with regards to the photo.  In order to enjoy Geotagging, you need a DSLR camera with GPS receiver.  In some mobile phone with GPS receiver, you have option to enable it.



This photo was taken during last day of Ramadhan




EXIF data extracted from this photo using EXIF Viewer add-ons for Firefox: -

EXIF IFD0
* Camera Make = Nokia
* Camera Model = C5-00
* Picture Orientation = normal (1)
* X-Resolution = 300/1 ===> 300
* Y-Resolution = 300/1 ===> 300
* X/Y-Resolution Unit = inch (2)
* Y/Cb/Cr Positioning (Subsampling) = centered / center of pixel array (1)

EXIF Sub IFD
* Exposure Time (1 / Shutter Speed) = 3329/1000000 second ===> 1/300.39051 second ===> 0.00333 second
* Lens F-Number / F-Stop = 240/100 ===> ƒ/2.4
* ISO Speed Ratings = 100
* EXIF Version = 0220
* Original Date/Time = 2010:09:09 18:31:44
* Digitization Date/Time = 2010:09:09 18:31:44
* Components Configuration = 0x01,0x02,0x03,0x00 / YCbCr
* Shutter Speed Value (APEX) = 8230/1000
Shutter Speed (Exposure Time) = 1/300.25 second
* Aperture Value (APEX) = 104/100
Aperture = ƒ/1.43
* Light Source / White Balance = unknown (0)
* Flash = Flash did not fire, auto mode
* Focal Length = 330/100 mm ===> 3.3 mm
* Maker Note =
* Last Modified Subsecond Time = 057
* Original Subsecond Time = 057
* Digitized Subsecond Time = 057
* FlashPix Version = 0100
* Colour Space = sRGB (1)
* Image Width = 2048 pixels
* Image Height = 1536 pixels
* Custom Rendered = normal process (0)
* Exposure Mode = auto exposure (0)
* White Balance = auto (0)
* Digital Zoom Ratio = 100/100 ===> 1
* Scene Capture Type = standard (0)
* Gain Control = n/a (0)

EXIF IFD1
* Compression = JPEG compression (6)
* X-Resolution = 72/1 ===> 72
* Y-Resolution = 72/1 ===> 72
* X/Y-Resolution Unit = inch (2)
* Embedded thumbnail image:



EXIF GPS IFD
* GPS Version ID = 0x02,0x02,0x00,0x00
* GPS Latitude Reference = N
* GPS Latitude = 4/1,6/1,595582470/10000000 [degrees, minutes, seconds] ===> 4° 6′ 59.55825″ == 4.116544°
* GPS Longitude Reference = E
* GPS Longitude = 101/1,8/1,10905214/10000000 [degrees, minutes, seconds] ===> 101° 8′ 1.09052″ == 101.133636°
* GPS Altitude Reference = sea level reference (negative value)
* GPS Altitude = 900/100 m ===> 9 m


From the GPS coordinates (N4.116544 E101.133636), it tells the location of the camera that took the photo above.





View Larger Map



Everything seems okay and we praise EXIF data on our outdoor photography.  Then we start taking photos of our family, relatives and friends that we visited during this festive season.  These photos later made available in social networking, blog, and online web album meant to be shared among friends and families or even to the public.  Oppsss!!  We just let strangers know where we live, where is our kampung, and where our relative live too?



Try it yourself on the following blog

1. Go to http://girodilento.com/?page=8 and read entry on "Back on the bike - Ferrari special"

2. Right click on that Ferrari F40 photo and select "View Image EXIF Data"

3. You can find the coordinate towards the end of the data.

4. Open it using Google Maps.



Thus, we ought to be careful of information that we share in the Internet.  Or shall I quote what Kapla Hodot told some time ago.. 



Internet Privacy is oxymoron!
Post a Comment