Sunday, 23 February 2014

Geo-tag: Detecting your location


  A few days back I uploaded a photo on Facebook. After uploading, I went on to add the location of the photo and Facebook offered a suggestion as to where the photo was taken. I looked at the first option; it was the exact location where I had clicked the pic.
             I tried to tag location of an old photo but this time it gave a wrong suggestion. It became pretty obvious that there had to be some difference in the properties of both the photos. When I compared the properties, I got to knew a whole new phenomenon known as ‘GEO – TAGGING’. We will find this keyword on specification list of almost all the new smartphones but it is mostly neglected .

What is Geo-tagging?

Geo-tagging is the process of adding geographical data such as latitude and longitude to various media like photos, video , websites ,RSS feeds. Or it can define the location place name or regional identifier. It can also include information such as the altitude and bearing.
              When our website or blog consists of geotags then it provides information to search engines or readers about the location of the site.

Geo-tagging photos

         There are a few methods of geo-tagging photographs, either automatic or manual. The simplest and the most precise option to geo-tag a photo would be to have a GPS enabled smartphone or camera. Thus, when we click a photo, the latitude and longitude of the location will be embedded onto the photo without our knowledge. These properties are stored in the metadata of pic or the Exif (Exchangeable image file format) FILE.
          Manual geo-tagging involves the use of software with which the properties of a photo can be manipulated.Several manufacturers, such as Sony, Panasonic, Fujifilm, Nikon are now providing cameras with built-in GPS feature which results in storing accurate data location in the photos or videos. 

The properties displaying the latitude and longitude.


Geo-tagged Websites
        Geo-tagging provides Internet users with a variety of features. For example, by entering the street address into Google Street View, users can get photographs taken from the street near the input location, with links to maps and satellite or aerial photographs of the area.
    Internet and computer geotagging can be performed by associating a geographic location with ‘Internet protocol (IP)’, WiFi and GPS co-ordinates.
    The combination of html 5, google maps and geo-location API has provided webmasters to add great new features to their websites.
     The easiest way to add geotags to a Web page is with meta tags. We create meta tag that includes the latitude and longitude in the contents of the tag:

<meta name="Example" content="48, -122" />
You can then add other meta tags that include the region, placename, and other elements (altitude, etc). These are named "geo.*" and the contents are the value for that tag. For example,
 <meta name="geo.placename" content="Mumbai" />
HTML 5 Geo-location API can only return users location in co-ordinates. Using these co-ordinates, the location can then be displayed on google maps.
W3C Geo-location API allows for scripted access to geographical location.
Geo-coding is the process of converting an address into latitude and longitude. Reverse Geo-coding is the process of converting latitude and longitude to human friendly address.
Google maps come in handy when we want to go a certain location but are not sure of how to get there. We just search for the location and then click on ‘Get Directions’.
Voila! We get a map with a specific route. All this has been possible due to the Geo-location API.
Some functions of the geo-location API:
getCurrentPosition( ) :This function is ued to get user’s position.
watchPosition( ): it gets the user’s current position and continues to update as user moves .(Specifically used in GPS)
Since the position can compromise user’s privacy, the position is not available till user approves it.
Examples :
Justdial.com
‘Near Me’ feature gives a list of restaurants, cinema halls or hospitals within a certain radius. 

ADVANTAGES AND DISADVANTAGES
Geo-tagging is being widely used on social networking sites such as Instagram, Facebook, Flickr. With the growing number of social users using geo-tagging, it has led to broader access of information. As geotagging focus on pinpointing people, important questions arise over privacy.
---Tejas S.Ekawade

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