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Sunday, November 8, 2015

depression in Bay of Bengal - rain photo ,EXIF and geo-tagging

The festival of Lights – Deepavali is just two days away.  It rained heavily in Chennai and in many parts of Tamil Nadu – it is a depression, a surge in the current wet spell in southern states.  IMD Press release reads : Depression over Bay of Bengal and Extremely Severe Cyclonic storm ‘Megh’ over Arabian Sea.  

A depression has formed over southwest Bay of Bengal and lay centred at 0830 hours IST of today, the 8th November, 2015 near latitude 10.7° N and longitude 83.7° E, about 460 km southeast of Chennai, it would move westnorthwestwards, intensify into a Deep Depression during next 24 hours and subsequently into a Cyclonic Storm. It would cross Tamil Nadu coast between Karaikal and Chennai close to Puducherry around 9th midnight.

This morning  driving on Beach Road [whilst waiting at couple of signals] – I took some photos from my mobile Camera and upon reaching home, uploaded on Facebook.  It queries whether I would like to add location to the photos it – I was stumped to notice that for each photo, it was suggesting  the exact location to be tagged – it read – Mandaiveli, Marina and then Triplicane.  Wondered how it is possible. It is known as ‘Geo-tagging’.

It is all from EXIF data.  Depending on the camera, EXIF data will store the current state of the camera when the photo was taken including date and time, shutter speeds, focal lengths, flash, lens type, location data, etc.  Modern smartphone embed GPS coordinates in each photo they take. Yes, those photos you’re taking have location data embedded in them — at least by default. Many modern digital cameras also do this.  Geotagging basically means that the longitude and latitude of the photo has been stored in the photo metadata. The metadata is the invisible part of the photo called EXIF data.

Exchangeable image file format (officially Exif, according to JEIDA/JEITA/CIPA specifications) is a standard that specifies the formats for images, sound, and ancillary tags used by digital cameras (including smartphones), scanners and other systems handling image and sound files recorded by digital cameras. This standard consists of the Exif image file specification and the Exif audio file specification.

The Japan Electronic Industries Development Association (JEIDA) produced the initial definition of Exif. Version 2.1 of the specification is dated 12 June 1998. The latest, version 2.3, released on 26 April 2010 and revised in May 2013, was jointly formulated by JEITA and CIPA. Exif is supported by almost all camera manufacturers.

The photos were taken on Nokia Lumia 730 which runs on  Windows  Phone operating system. The Lumia name is derived from the partitive plural form of the word 'lumi', which means 'snow' in the Finnish language, and Estonian as well.

Technology often is amazing !

With regards – S. Sampathkumar

8th Nov. 2015

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