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Image Geotagging

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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, accuracy data, and place names.[1]

Geotagging standards in electronic file formats:

  1. JPEG photos
  2. HTML pages: ICBM method, RDF feeds, Microformat, Wikipedia, Geotagging in tag-based systems & Geoblogging

the most famous API and Application on image geotagging is exiftool. [2]

Geotagging with ExifTool[3]
The ExifTool geotagging feature adds GPS tags to images based on data from a GPS track log file. The GPS track log file is loaded, and linear interpolation is used to determine the GPS position at the time of the image, then the following tags are written to the image:

  • GPSLatitude
  • GPSLatitudeRef
  • GPSLongitude
  • GPSLongitudeRef
  • GPSAltitude
  • GPSAltitudeRef
  • GPSDateStamp
  • GPSTimeStamp

Currently supported GPS track log file formats:

  • GPX
  • NMEA (RMC, GGA, GLL and GSA sentences)
  • KML
  • Garmin XML
  • Magellan eXplorist PMGNTRK

Test Website:

  1. http://regex.info/exif.cgi
  2. http://locr.com

Examples: [4]

  • READING EXAMPLES
  • WRITING EXAMPLES
  • COPYING EXAMPLES
  • RENAMING EXAMPLES
  • GEOTAGGING EXAMPLES
  • PIPING EXAMPLES

EXIF stands for “Exchangeable Image File Format”. This type of information is formatted according to the TIFF specification, and may be found in JPG, TIFF, PNG, MIFF and HDP images, as well as many TIFF-based RAW images, and even some AVI and MOV videos. [5]

Applications based on exiftool:

[1] http://en.wikipedia.org/wiki/Geotagging
[2] http://www.sno.phy.queensu.ca/~phil/exiftool/
[3] http://www.sno.phy.queensu.ca/~phil/exiftool/geotag.html
[3][oldlink] http://cpansearch.perl.org/src/EXIFTOOL/Image-ExifTool-7.82/html/geotag.html
[4] http://www.sno.phy.queensu.ca/~phil/exiftool/exiftool_pod.html
[5] http://www.sno.phy.queensu.ca/~phil/exiftool/TagNames/EXIF.html
[6] http://www.sno.phy.queensu.ca/~phil/exiftool/#links

Written by v4ks1n

10/09/2009 at 18:23

Posted in blackberry, twitter

Tagged with , , , , , , , ,

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2 Responses

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  1. ExifTool now also supports IGC track logs. (I know, it’s hard to keep up with the new exiftool features.)

    Also, you should change reference 3 to

    http://www.sno.phy.queensu.ca/~phil/exiftool/geotag.html

    because the version-specific page on cpansearch will disappear eventually.

    Phil Harvey

    11/09/2009 at 12:02

    Reply

    • Thanks Phil Harvey,
      i think it’s really great if any API for many others programming language. 😉

      I will update the link.

      thanks!

      v4ks1n

      29/09/2009 at 09:27

      Reply

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