Geotagging (photography)

from Wikipedia, the free encyclopedia
Track with geo-referenced images

Under geotagging , and geocoding or Geo-Imaging , refers to the assignment of the case of photographic shots geographical coordinates . The georeferenced images can then be more easily searched for and selected as points on an electronic map .

application

Photo location is used in spatial planning and tourism, environmental planning, traffic and disaster control. A frequent and common application example is the time-saving illustration of a city tour laid down in a city map with pictures of interesting monuments. Another focus in the use of geo-imaging is environmental protection. Special biotope maps can be provided with current detailed images to save time. If such maps are created over a longer period of time, changes in the biotope can be displayed very easily.

technology

The geographical coordinates of the location of the photograph are determined directly with a GPS receiver when taking the picture or are later taken from a map. With special hardware, they are added to the metadata ( Exif ) of the images directly when taking the picture , otherwise later on the computer .

Location directly upon admission

Photo GPS with compass on GPS enabled camera

The advantage of direct localization is the low workload due to the automated geo-imaging process. GPS-enabled digital cameras are required to save the coordinates directly when taking a picture. Nikon introduced the first digital cameras with a GPS interface in 2001 with the D1H and D1X. A distinction must be made between models that acquire their location information via externally connected GPS receivers and those with an integrated GPS function. The latter includes the Ricoh Caplio 500SE and the Nikon Coolpix P6000. GPS is now being integrated into small travel cameras such as the Panasonic Lumix DMC-TZ10. Various PDAs or mobile phones that have a camera and GPS functionality can also enter GPS values ​​in the Exif data natively or by using special software or patching the existing software. This is for example with the PDAs HTC P3300 (XDA Orbit, MDA Compact III), HTC P3600 (HTC Trinity, VPA Compact GPS) or HTC TyTN II (MDA Vario III, VPA Compact V), the Apple iPhones 3G and newer, Nokia N96 and Nokia 5800 XpressMusic possible. When mounting a special photo GPS on the hot shoe, the direction of view of the image can also be recorded with an integrated electronic compass.

Subsequent location via GPS log

GPS data logger

If the coordinates are to be added later, it is necessary to record GPS tracks while taking photos. For this you can use outdoor GPS devices with a log function of the route, GPS PDAs with a log program or special GPS loggers. Using software, the coordinates from the track can then be assigned to the images using the time stamp. Frequent errors result from an inadequate comparison of the camera time and GPS time stamp. Therefore, you should compare the times before use or (also afterwards) photograph the time display of the GPS device or a radio clock in order to be able to compensate for the time difference.

Subsequent location by map

Various programs can also be used to locate individual images at a later date. To do this, the desired position is determined on the map and the coordinates are added to the image. Some web solutions such as locr offer this function. In the desktop area there are solutions from Digikam (Linux, MacOS, Windows) as well as the freeware program GeoSetter (see web links).

Display of the GPS photos

The geocoded images can be displayed on a map on various websites. The providers of these services include Flickr , Locr , Picasa . As a desktop solution, Google Earth also incorporated images from the Panoramio web service until February 2018 . In addition to GPS information, locr also evaluates compass information stored in the image and displays it on the map.

Geotagging for photo management and search

With the “Map Search Tool” plug-in, the Digikam image management system enables local image stocks to be filtered using a selection of rectangles on an electronic map.

See also

Web links
  • GeoTag (Open Source) for adding / editing geographic coordinates with Java
  • GpsPrune (Open Source) for editing GPS tracks and photo coordinates with Java

Individual evidence

  1. ↑ Description of the GPS interface of the Nikon D1X / D1H (2001)
  2. ↑ Product description and short test at digitalkamera.de
  3. ↑ Product description at Solmeta.com (engl.)
  4. ↑ Digikam Map Search Tool ( Memento of the original from June 5, 2009 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. accessed on June 23, 2009  @1@ 2Template: Webachiv / IABot / www.digikam.org