Trekka

This page is used to visualize and convert tracks, routes, and waypoints in the GPX, KML, Top50 OVL and PathAway format. Many GPS devices may record the covered track and store it into a file. This is interesting for people who carry a recording GPS device during their outdoor activities.

Upload your GPX-, KML-, Garmin PCX5, Top50 OVL- or PathAway PWTRK-files using the form or select one of my favorite tracks from the list. The browser displays than the tracks and points on the map. It is possible to zoom and move the map with the buttons or the mouse. Additional information about the track, like elevation profile, length, and duration are computed and displayed as well.

Features: This service uses the API and the data of Google Maps.

Upload Track

Click at Browse and select a file with tracks, routes, and/or waypoints. Following formats are supported:

Read-out ActivTrk

The internal file ActivTrk.Trk exists at all GPS devices of the Magellan Triton series. It contains the track log of the active track. There are two methods to read-out this file from the device:

Track list

Select a track from the list. The tracks are sorted according to regions which can be choosed in the upper part of the list.

Track info

The information of a track contain: If this information is missing or incomplete, then it can't be determined form the data. If for example the track file contains only waypoints, but no track, the the track information box is totally empty.

Track optimization

GPS receivers write the actial postion into the track log at regular intervals. This is normally triggered by time or destination, i.e. a coordinate is recorded for example every 10 seconds or once per 100 meter. If the receiver is now moved along a straight line, then the track log contains more than enough points, because a straight line may be described by only two points.

Trekka contains an algorithm to solve this issue as it tries to identify straight lines and remove needless points. The efficiency of this algorithm can be identified by looking at the Track info. Here the number of points before and after the track optimization is displayed.

Pause detection

If the track log contains time stamps, then Trekka may compute the actual speed at each part of the track. A pause is detected if the actual speed is less than 0.5 km/h for at least 5 minutes. This place is marked at the map and the Track info shows then the total duration of all pauses and the average speed adjusted for pauses.

Elevation profile

If the track log contains elevation data, then an elevation profile is computed and displayed.

Alternative DEM data is available for some regions of the world. It can be used to compute the profile as well.

DEM data

If a track covers a region for which digital elevation data is available, then the menu contains the text Additional elevation data is available. After clicking the link Use it! the elevation profile as well as the values for ascent and descent are computed again using that data.

Therefore it is possible to create elevation profiles for tracks which contain no elevation data itself. Of course the downloadable GPX-/KML-file contains the DEM data as well.

DEM: Digital elevation model.

Menu

The menu is used to control all further actions: Only meaningful menu items are visible. If for example the track log contains no time stamps, then the menu item Upload photo is not visible.

Photo Geotagging

If you took photos during the tour then this tool will help to geotag them. This means to add EXIF metadata for geographic latitude and longitude to the image file. The assignment takes place by matching the time stamps contained in track and photo. This is useful if you want to upload your photos to sites like Flickr or Panoramio