Animating a GPS track

So you had a great flight. You unload your GPS and now have a GPX file. How do you share the experience with others?

Well, draw it on a map like so:

Boring display of a great flight

Pretty bland, if you ask me – “yes, we’ve been here and there too”. in Flatlandia, that is. The dynamics of the flight experience, great views – gone.

You could generate a KML file and tell folks to view it in Google Earth. Works, if they have Earth installed – which translates into “almost nobody”. With an advanced degree in Earth, you can even create an animation video. But that takes time and lots of moving files around.

What I’m looking for is – send out a link, and everybody with a browser at hand could re-live the flight, drag, pan, and zoom around like so:

and.. also be able to embed this on a web page.

Do-it-yourself like so:

  • create a free account on Rikitraki.com
  • upload your GPX file
  • click the “3D” icon and the Play button

That’s it!

Another option: ayvri.com

Turns out there are several sites which provide similar services. Ayvri.com also sports free accounts, with the option to upload GPX files. Other than rikitraki.com ayvri optionally displays current flight data (speed, altitude, climb/sink rate, distance, time) – very nice!

Click the image below to run the actual animation on ayvri.com:

Flight animation with ayvri.com.

Pretty much the same drill as above:

  • create a free account on https://ayvri.com
  • upload a GPX file and describe the flight
  • click “Create Scene”
  • click the “Stats” dropdown (right top) for flight data
  • view the animation
  • record its URL for sharing.

While rikitraki seems to be more of a single-programmer hobby project, ayvri looks more professional and polished, with a company, free/paid options, an API and a Twitter & Facebook presence behind it.

Creating tracks for Google Earth from GPX files

Google Earth is a great viewer for flight tracks. While GPX files can be imported into GE, they do not look appealing – and lack useful information.

Enter gpsvisualizer.com: a free online service to convert GPX files to the GE KML format (among many other features). I mostly use the Convert your GPS data for use in Google Earth service to visualize flights with these settings:

  • Google Earth doc name: start, destination & day of flight
  • Colorize by: Speed
  • Altitude mode: Absolute (for flights)
  • Draw a shadow: 30% opacity – yields an actual track over ground

Tip: click Save these settings and next time all settings will be restored.

Gpsvisualizer.com parameter settings

The result is a compressed KML file which looks like so when openend in Earth:

Update:

Many GPS sources create lots of trackpoints – so much that the resulting tracks look like a series of balls. Way too dense to be useful.

Also, the line segments generated by the settings above lack useful information (just text like ‘trkpt 660’). Adding waypoints in gpsvisualizer adds more detail.

Hour marks, as well as time stamps for takeoff and landing time are lacking above.

A good setting to deal with these issues is:

  • “Trackpoint distance threshold” : 20m
  • “Draw as waypoints”: Yes, named with timestamps
  • “Tickmark interval”: 1h
  • “Zero distance mark”: Yes (this field only appears when you enter a value into “Tickmark interval”)

This gives us waypoints every 20m (good enough) and klicking them in GE reveals useful information:

Clicking a waypoint. Note timestamp on takeoff location

The updated result file can be downloaded here.