Track (GNSS)
A track ( engl. Track : distance traveled or its tracks) is an ordered list of points with coordinates that describe a route. The comparison with the breadcrumbs that Hansel and Gretel scattered in order to find their way back is often mentioned as an illustration . The counterpart to a track is the route , which is a planned route and consists of a sequence of (mostly) independent waypoints .
recording
If a track was created from a recording with a GNSS receiver such as GPS or GLONASS , it is also referred to as track log ( English for protocol, see logbook ). In this case, each coordinate also contains the date and time. Depending on the recording device used, the altitude , temperature , water depth and water temperature are also saved. Usually, the points are recorded at short intervals; the reception and the recording can also take place on two separate devices that communicate with each other via NMEA .
With the Douglas-Peucker algorithm , such tracks can be reduced to the essential points in post-production. Some devices save more track points when changing direction (i.e. in curves) than on straight sections. In this way, the distance covered can be recorded in great detail and storage space saved at the same time.
accuracy
The accuracy of recorded tracks is limited by the accuracy of the receiver and the recording interval used. In addition, some devices smooth out rapid changes in direction in order to obtain “nicer” tracks that have been freed from noise , and to prevent permanent wandering of the position when stationary. Another factor is the use of dead reckoning when satellite reception is disturbed.
presentation
When displaying tracks, the individual points are usually connected with straight lines so that the route can be recognized even if the points are far apart. This is often the case when a track was not recorded but drawn on the computer. In principle, it can be displayed with or without an underlying map.
Data formats
Tracks can be saved in a variety of different data formats. GPX is widely used as an exchange , as it can read and write many programs. Google's own KML format is also widespread.
In aviation, tracks are saved in IGC format, which also contains a digital signature to ensure protection against forgery.
use
Tracks can be used both for private purposes and professionally. When evaluating a recorded track, in addition to the distance covered, you also get the speed and altitude profile.
Tracks are used, for example, to pass on a nice cycling or running route. There are numerous websites dedicated to track sharing. Maps are also created with the help of tracks, especially the free OpenStreetMap . For competitions in aviation, such as the online contest or the Paragliding World Cup , track logs are evidence of the distance actually covered or the circumference of buoys . The track logs thus replace the previously complex flight documentation and evaluation of photographs. In addition, this gives other pilots the opportunity to understand the flights of others and thus improve their own flight technique.
See also
- GPSies.com , an online community where you can contribute GPS tracks
further reading
- M. Bauder: GPS recording and GIS analysis of individual mobility . Freiburg Document Server, 2011. ( Download )
- M. Bauder: Experiences from GPS tracking of individual mobility of tourists. Consequences for further development as a new human geographic method. In: J. Strobl, Th Blaschke, G. Griesebner (Eds.): Applied Geoinformatics 2012 . Contributions to the 24th AGIT Symposium Salzburg. Wichmann, 2012, pp. 420-429.
- H.-J. Weber: City tourism in Berlin: Possibilities for GPS-based localization of tourist practices. In: A. Zehrer, A. Grabmüller (Ed.): Tourism 2020+ interdisciplinary . ESV Verlag, 2012, pp. 65–78.
- H.-J. Weber, T. Freytag: Streams of tourist mobility in Berlin. Maps, posted March 16, 2012 via @ international interdisciplinary tourism magazine, 2012: http://www.viatourismreview.net/Carte1_DE.php
- H.-J. Weber: The paradox of city tourism: between mass tourism and individuality: A study on tourist practices and mobility using GPS and questionnaire data as well as travel guide literature using the example of the city of Berlin. Mensch und Buch Verlag, Berlin 2012, ISBN 978-3-86387-261-8 .
- H.-J. Weber, M. Bauder: New methods of mobility analysis: The connection of GPS tracking with quantitative and qualitative methods in the context of tourism. In: spatial research and spatial planning. 2013, Volume 71, Issue 2, pp. 99–113.