GPSdings

gpsdings usage example: a mountain hike in the Alps

Windows cmd.exe syntax is used throughout this example.

Unix shells: Replace the ^ line continuation character with \. You might want to define an alias for gpsdings, e.g.

alias gpsdings='java -jar /absolute/path/to/gpsdings.jar'

which will allow you to invoke gpsdings from any working directory by simply typing gpsdings. If you use gpsdings frequently you can add the above line to your .bashrc or equivalent configuration file.

Before the trip

• We load the digital topographical map Austria West into the EADS-GeoGrid-Viewer that comes with the German Top 50 maps, and draw our planned trip. We save it as an ASCII overlay file guffertrunde-planned.ovl.
• We convert the ovl file to gpx with

  java -jar gpsdings.jar gpxovl guffertrunde-planned.ovl

  and obtain the file guffertrunde-planned.gpx.
• We load this file into gpsbabel or GPS Trackmaker and copy the planned track into the memory of the gps receiver. With the Garmin Geko 201, for example, you have two options: if you copy the track into the active log of the receiver it will show up on the map page of the receiver as a breadcrumb trail. If you copy it into one of the saved track slots (these have some limitations) you can follow it using TracBack^® (see p. 18 of the owner's manual). In either case you should make sure that the whole planned track has been copied to the receiver by transferring it back to the computer and comparing it to the original.

During the trip

• We synchronize the clock of our digital camera to the GPS time. We are in time zone UTC+002 (CEST). This corresponds to an UTC offset of 2 × 60 × 60 = 7200 seconds.
• We follow the planned track, which is displayed in the map page of the gps receiver.
• We let the GPS receiver record our track. From time to time we take a picture with our camera, and we mark some waypoints at special locations like the summit.

After the trip

• We download the recorded track from the receiver and save it as GPX 1.1 with gpsbabel or GPS Trackmaker.
• (Optional) We delete the hand-drawn track segment from the gpx file in a text or xml editor. We can recognize it from the fact that its track points all have the same time stamp or no time information at all.
  We also remove track points with large errors that were recorded when the receiver had poor sky view, and we add some meta-information. The result is guffertrunde.gpx.
• We let gpsdings create a Google Earth kmz file with nice waypoint symbols:

  java -jar gpsdings.jar gpxkml --kmz --name=Guffertrunde guffertrunde.gpx

  The result is guffertrunde.kmz
• We download the digital camera pictures and put them in a folder called photos-original.
• Now we write copies of our digital camera pictures that are geostamped both in their exif header (--Exif) and in the actual image (--stamp) to the folder photos.

  java -jar gpsdings.jar exifloc --utc-offset=7200 --Exif ^
    --copy-to photos --gpx guffertrunde.gpx --stamp @mypattern.html S 0.8 ^
    photos-original\*.jpg

• Then, we create a Google Earth photo kmz file and a GPX file with waypoints for the photographs:

  java -jar gpsdings.jar exifloc --image-size 200 200 --read-gps-tag ^
    --kmz guffertrunde-photos.kmz --GPX guffertrunde-photos.gpx photos\*.jpg

  The result is guffertrunde-photos.kmz. It contains copies of our digital camera pictures that are scaled down so that they fit into a 200 px × 200 px square.
• Finally, we make gpsdings plot some graphs:

  java -jar gpsdings.jar trackanalyzer --plot ^
    "TimeTravelled|DistanceTravelled|graph1.svg|Guffertrunde" ^
    guffertrunde.gpx
  java -jar gpsdings.jar trackanalyzer --plot ^
    "DistanceTravelled|Elevation|graph2.svg|Guffertrunde" ^
    guffertrunde.gpx
  java -jar gpsdings.jar trackanalyzer --smoothing=5 --plot ^
    "TimeTravelled|VerticalSpeed|graph3.svg|Guffertrunde" ^
    guffertrunde.gpx

  The result is graph1.svg, graph2.svg, graph3.svg.