An hour or three later, I don’t think there is any way to get Google Earth to replay a GPS track file in real time. Only if the data is arriving via a COM port (NMEA etc) or similar.
I have also found that it’s not trivial to get a GPS track logger which records the samples exactly as configured e.g. one per second. The last one I tried records a GPS file like this
in which you can see it “sometimes” does it 1 sec apart, but mostly not 
However the date/time is recorded so if the app doing the replay works from that, that should work. The KML file format doesn’t contain date/time so that cannot possibly work for real time:
However, I am not so sure that for a movie inset moving map, one always wants an auto-scrolling map…
This is a quick and dirty movie showing a capture from Ozi running a GPS track. I have not verified this but I think that when the replay speed on the Track Replay Control is set to just 1, it is real time. You just don’t get an auto scrolling map with Ozi – it jumps when it reaches the edge. And you can’t customise the aircraft symbol.
That’s neat but isn’t so good on a raster map
Well it is a raster map that is used for this video, as are all tiled maps like OSM or Google Maps are. If you have it in OziExplorer already, is there no way of exporting tiles from the map? Another source for tiles could be SkyVector
And if you want the map North-Up, with a rotating Aircraft symbol, that should be two lines changed in this OpenSource renderer.
As you see from the above movie, I have the principle working. I can capture that application window to an MP4 – that’s how the above movie was made. That’s directly usable as an inset for a flying movie. No need to export tiles, etc.
I have emailed Oziexplorer to ask whether at x1 speed it is exactly real time. I think it probably is… They do very occassionally reply to comms.
Ideally having a better symbol for the aircraft (not just a dot) would be better. I don’t know how to do that presently.
Whatever solution is used for a real time replay needs to use a GPX or some other format, not KML which has no time stamps.
Any solutions, I am all ears I didn’t find anything on Skyvector.
This looks promising.
Peter wrote:
Only if the data is arriving via a COM port (NMEA etc) or similar.
That’s trivial to do though using a virtual COM port. Just iterate through your GPX file and output a valid NMEA sentence every time the time stamp matches the ‘current’ second.
You could even interpolate the values so there’s a sentence every second.
That said, I’ve just had a look at the tool that TobiBS posted and don’t really understand why you don’t think it’s suitable. It seems perfect.
The Skyvector link is just a forum thread. I must be missing something.
Just iterate through your GPX file and output a valid NMEA sentence every time the time stamp matches the ‘current’ second.
Of course anything is possible if you volunteer to write code for it
That’s trivial to do though using a virtual COM port. Just iterate through your GPX file and output a valid NMEA sentence every time the time stamp matches the ‘current’ second.
With stuff like GPSGATE, sure. That is yet another level of hassle though. But you still need to squirt the data at the VCP in real time. This approach is really for a real GPS whose data of course comes out in real time.
Real time playback needs the player to use the time stamps.
Yes but you could write a script to do that in a matter of seconds – it’s trivial.
Come on, Steve…………….
e-mail me a chunk of your GPX file and I’ll do it for you.
Steve – thank you for your offer but I don’t want to be setting up a VCP on my PC just so I can feed Google Earth with GPS data from a fake GPS. I use the PC for testing various USB/serial hardware, etc. There have to be simpler ways of doing this, and involving less hacking of the computer.
If OTOH you can find a way to create
then I am all ears.
Peter wrote:
Ideally having a better symbol for the aircraft (not just a dot) would be better. I don’t know how to do that presently.Whatever solution is used for a real time replay needs to use a GPX or some other format, not KML which has no time stamps.
RaceRender can do that pretty well. It’s possible to add a still map image as background to the track (which they haven’t done here). Still no moving map though.
