Geotagging
Geotagging, or GeoTagging, is the process of adding geographical identification
Geotagging can help users find a wide variety of location-specific information from a device. For instance, someone can find images taken near a given location by entering latitude and longitude coordinates into a suitable image
The geographical location data used in geotagging can, in almost every case, be derived from the
The related term
Applications
In social media
Geotagging is a popular feature on several social media platforms, such as Facebook and Instagram.
Facebook users can geotag photos that can be added to the page of the location they are tagging. Users may also use a feature that allows them to find nearby Facebook friends by generating a list of people according to the location tracker in their mobile devices.[2]
Instagram uses a map feature that allows users to geotag photos. The map layout pin points specific photos that the user has taken on a world map.
Photos
Two main options can be used to geotag photos: capturing GPS information at the time the photo is taken or "attaching" geocoordinates to the photograph after the picture is taken.
In order to capture GPS data at the time the photograph is captured, the user must have a camera with built in GPS or a standalone GPS along with a digital camera. Because of the requirement for wireless service providers in United States to supply more precise location information for 911 calls by September 11, 2012,[3] more and more cell phones have built-in GPS chips. Most smart phones already use a GPS chip along with built-in cameras to allow users to automatically geotag photos. Others may have the GPS chip and camera but do not have internal software needed to embed the GPS information within the picture. A few digital cameras also have built-on or built-in GPS that allow for automatic geotagging.[4]
Devices use GPS, A-GPS or both.
Remote sensing data
In the field of remote sensing the geotagging goal is to store coordinates of every pixel in the image. One approach is used with the orthophotos where we store coordinates of four corners and all the other pixels can be georeferenced by interpolation. The four corners are stored using GeoTIFF or World file standards. Hyperspectral images take a different approach defining a separate file of the same spatial dimensions as the image where latitude and longitude of each pixel are stored as two 2D layers in so called Input geometry data (IGM) files,[5] also known as GEO files.
Audio/video files
Audio/video files can be geotagged via: metadata, audio encoding, overlay, or with companion files. Metadata records the geospatial data in the encoded video file to be decoded for later analysis. One of the standards used with
GEO_LOCATION=(decimal latitude);(decimal longitude);([optional]elevation in meters)
for example:
GEO_LOCATION=35.1592;-98.4422;410
SMS messages
The
I'm at the pub geo:-37.801631,144.980294;u=16
DNS entries
RFC 1876 defines a means for expressing location information in the
HTML pages
ICBM method
The GeoURL[9] method requires the ICBM tag[10] (plus optional Dublin Core metadata), which is used to geotag standard web pages in HTML format:
<meta name="ICBM" content="50.167958, -97.133185">
The similar Geotag format allows the addition of place name and region tags:
<meta name="geo.position" content="50.167958;-97.133185">
<meta name="geo.placename" content="Rockwood Rural Municipality, Manitoba, Canada">
<meta name="geo.region" content="ca-mb">
RDF feeds
The RDF method is defined by W3 Group and presents the information in RDF tags:[11]
<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns:geo="http://www.w3.org/2003/01/geo/wgs84_pos#">
<geo:Point>
<geo:lat>55.701</geo:lat>
<geo:long>12.552</geo:long>
</geo:Point>
</rdf:RDF>
Microformat
The Geo microformat allows coordinates within HyperText Markup Language pages to be marked up in such a way that they can be "discovered" by software tools. Example:
<span class="geo">
<span class="latitude">50.167958</span>;
<span class="longitude">-97.133185</span>
</span>
A proposal has been developed[12] to extend Geo to cover other bodies, such as Mars and the Moon.
An example is the
In tag-based systems
No industry standards exist, however there are a variety of techniques for adding geographical identification metadata to an information resource. One convention, established by the website
geotagged
geo:lat=57.64911
geo:lon=10.40744
This describes the geographic coordinates of a particular location in terms of
Using three tags works within the constraint of having tags that can only be single 'words'. Identifying geotagged information resources on sites like
geo:lat=
and geo:lon=
are necessarily very variable.
Another option is to tag with a Geohash:
geo:hash=u4pruydqqvj
A further convention proposed by FlickrFly adds tags to specify the suggested viewing angle and range when the geotagged location is viewed in Google Earth:
ge:head=225.00
ge:tilt=45.00
ge:range=560.00
These three tags would indicate that the camera is pointed heading 225° (south west), has a 45° tilt and is 560 metres from the subject.
Where the above methods are in use, their coordinates may differ from those specified by the photo's internal Exif data, for example because of a correction or a difference between the camera's location and the subject's.
In order to integrate geotags in social media and enhance text readability or oral use, the concept of 'meetag' or tag-to-meet has been proposed. Differing from hashtag construction, meetag includes the geolocation information after an underscore. A meetag is therefore a word or an unspaced phrase prefixed with an underscore ("_"). Words in messages on microblogging and social networking services may be tagged by putting "_" before them, either as they appear in a sentence, (e.g. "There is a concert going _montreuxjazzfestival", "the world wide web was invented _cern _geneve", ...) or appended to it.[13]
Geoblogging
Geoblogging attaches specific geographic location information to blog entries via geotags. Searching a list of blogs and pictures tagged using geotag technology allows users to select areas of specific interest to them on interactive maps.[14]
The progression of
For better integration and readability of geotags into blog texts, the meetag syntax has been proposed, which transforms any word, sentence, or precise geolocalization coordinates prefixed with an underscore into a 'meetag'. It not only lets one express a precise location but also takes in account dynamically changing geolocations.
Wikipedia article geosearching apps
One of the first attempts to initiate the geotagging aspect of searching and locating articles seems to be the now-inoperative site Wikinear.com, launched in 2008, which showed the user Wikipedia pages that are geographically closest to one's current location.[15]
The 2009 app Cyclopedia works relatively well showing geotagged Wikipedia articles located within several miles of ones location, integrated with a street-view mode, and 360-degree mode.
The app Respotter Wiki, launched in 2009, claims to feature Wikipedia searching via a map, also allowing users to interact with people around them, via messaging and reviews, etc. The app, in its current function, however, seems to give only geotagged photo results.
As of 2017, the Wikipedia-World Project provides a simple map search tool which can display tagged articles near to a particular location, as well as a variety of more sophisticated tools integrated with external mapping services.[16]
Dangers
Following a scientific study[17] and several demonstrative websites,[18][19] a discussion on the privacy implications of geotagging has raised public attention.[20][21][22][23] In particular, the automatic embedding of geotags in pictures taken with smartphones is often ignored by cell-phone users. As a result, people are often not aware that the photos they publish on the Internet have been geotagged. Many celebrities reportedly gave away their home location without knowing it.[citation needed] According to the study, a significant number of for-sale advertisements on Craigslist, that were otherwise anonymized, contained geotags, thereby revealing the location of high-valued goods—sometimes in combination with clear hints to the absence of the offerer at certain times. Publishing photos and other media tagged with exact geolocation on the Internet allows random people to track an individual's location and correlate it with other information. Therefore, criminals could find out when homes are empty because their inhabitants posted geotagged and timestamped information both about their home address and their vacation residence. These dangers can be avoided by removing geotags with a metadata removal tool for photos before publishing them on the Internet.[citation needed]
In 2007, four
Another newly realized danger of geotagging is the location information provided to criminal gangs and poachers on the whereabouts of often endangered animals. This can effectively make tourists scouts for these poachers, so geotagging should be turned off when photographing these animals. According to Chinoitezvi Honour, some phones automatically geotag pictures hence location should be turned off when taking pictures.
See also
- Geocaching
- Geographic information system (GIS)
- Georeferencing
- Geomessaging
- GeoRSS
- geo URI scheme
- ISO 6709, standard representation of geographic point location by coordinates
- Supranet
- Tag (metadata)
- Toponym resolution
References
- ^ "GPS adds dimension to online photos". The Oklahoman. Oklahoma City, OK. Associated Press. 22 January 2008. Archived from the original on 24 September 2021. Retrieved 21 September 2020.
- ^ "Facebook's New Mobile Feature For Finding People Around You". 24 June 2012. Retrieved 2016-04-19.
- ^ "Wireless 911 Services". Retrieved 2010-07-15.
- ^ "Photographers Have Several Camera Options for Geotagging Pictures with GPS Points". Archived from the original on 2018-06-23. Retrieved 2018-06-23.
- Exelis. Retrieved 29 April 2015.
- ^ MISB Standard 0601
- ^ "Airborne Geospatial Video Recorders, Cameras, and Systems".
- ^ "VorbisComment – XiphWiki". wiki.xiph.org.
- ^ "Adding yourself to GeoURL". Archived from the original on 2008-05-15. Retrieved 2008-07-30.
- ^ The Internet Engineering Task Force. "Geographic registration of HTML documents". Retrieved 2008-07-30.
- ^ W3C Semantic Web Interest Group. "Basic Geo (WGS84 lat/long) Vocabulary". Retrieved 2008-07-30.
{{cite web}}
: CS1 maint: numeric names: authors list (link) - ^ "Geo Extension Straw-Man Proposal". Retrieved 2007-12-28.
- ^ "Web page for the 'meetag standard' proposition". Archived from the original on 2014-07-14.
- ^ "Example of pictures with geotag, using mobile phone". Archived from the original on 2015-02-13. Retrieved 2009-09-21.
- ^ Willison, Simon. (2008). "Wininear.com, OAuth and Fire Eagle", SimonWillison.net, Mar 22 2008
- ^ "Geo-link". tools.wmflabs.org.
- ^ "G. Friedland, R. Sommer: "Cybercasing the Joint: On the Privacy Implications of Geo-Tagging", 5th Usenix Hot Topics in Security Workshop (HotSec2010), Washington DC, August 2010" (PDF). Retrieved 2013-12-23.
- ^ "Please Rob Me". www.pleaserobme.com.
- ^ "icanstalku.com". icanstalku.com. Retrieved 2013-12-23.
- YouTube
- ^ Heussner, Ki Mae, "Celebrities' Photos, Videos May Reveal Location", ABC News, July 16, 2010
- ^ Geo-tags reveal celeb secrets, 12 July 2010, by Jim Giles, New Scientist
- ^ Murphy, Kate (11 August 2010). "Web Photos That Reveal Secrets Such As Where You Live / "MythBusters" host inadvertently reveals his home address on Twitter". The New York Times. Retrieved 2013-12-23.
- ^ "Geotagging poses security risks". Army.mil. Retrieved 2013-12-23.
Further reading
- Luo, Jiebo; Joshi, Dhiraj; Yu, Jie; Gallagher, Andrew (2011). "Geotagging in multimedia and computer vision—a survey". Multimedia Tools and Applications. 51 (1). Springer: 187–211. S2CID 7433108.
External links
- Media related to Geotagging at Wikimedia Commons