Request: Support for altitude data in track logs

[skivvie]

[As a paraglider pilot, I'd LOVE to see imported .gpx files containing tracks actually show altitude data in Google Earth, instead of laying track files flat on the terrain.

Is there a way to do this that I'm missing? Or is altitude data just not integrated?

Sorry if this isn't directly KML related... didn't know where else to post =]

[ink_polaroid]

The defult mode for new placemarks is "clamped to ground".

If your gpx file has altitude data, this should be preserved during import. If you'd like to see the placemarks at altitude, right-click on the imported folder you want to change (i.e. Waypoints), select edit, then location, and adjust the altuitude mode to relative or absolute. (Selecting extrude will also tether the mark to the ground with a vertical line you can style.)

[skivvie]

Thanks for the reply ink!

I hadn't noticed those options... but alas they don't seem to do the trick.

The gpx file does contain altitude data, but the altitude isn't plotted in any of those modes.

Clamped to Ground:
Obviously, path follows terrain.

Relative to Ground:
Same as above, path follows contour of terrain, only it is offset vertically by the value selected with the altitude slider

Absolute:
The path is flat on a plane, but it's height can be moved vertically with the altitude slider.

Again, none of those options actually plot the altitude of each point in the track log. I'm attaching a sample flight log from a recent paragliding flight as an example.

I hope I'm missing something... but if not, is there hope of this ability being integrated? I know a LOT of pilots who'd start using GE Plus instead of the other mostly half baked or too expensive options out there. Thanks again!

-loren

[ink_polaroid]

Hm.

Okay, I've taken a very quick look and I think that the problem seems to stem from the difference between waypoints and tracks. Waypoints with <ele> values are correctly drawn at height, whereas <ele> in tracks is ignored.

I reserve the right to be completely wrong about that, though.

[mcshea98]

skivvie and ink_polaroid,

If you put the coordinates into the kml file in the following format, then choose absolute, it will work.

<coordinates>
-98.281,32.3474,0 -98.414,32.780,50000
</coordinates>

Here is a sample. Edit the kml in notepad and you will see.

[ink_polaroid]

Um. Yes. That works fine.

But the point of gpx import is that one doesn't have to hack around with notepad or edit files.

Did I turn two pages at once again?

[skivvie]

[

Quote:

---

Hm.

Okay, I've taken a very quick look and I think that the problem seems to stem from the difference between waypoints and tracks. Waypoints with <ele> values are correctly drawn at height, whereas <ele> in tracks is ignored.

I reserve the right to be completely wrong about that, though.

---

Hm... so how can I import a track as a bunch of waypoints? After saving out the KML file of the track after it's imported, there's definitely no altitude info in it, so you're correct that it just ignores it. How do we file this as a bug? =]

[robvree]

As another paraglider, I too would love to see this feature work correctly. I played around with it more and ink_polaroid is correct. It seems as though the elevation tag is ignored for tracks. I used GPSBable to convert a .GPX file into a .KML waypoint file. Imported into Earth and then set the waypoints to Absolute. All the points then show up at the correct altitude, but since each point is a waypoint and not a track point, there is no line connecting each of the point.

Please fix this bug so that the elevation tag is rendered correctly for track logs. That would be a great start to making this app useful for soaring pilots.

Take a look at other applications like CompeGPS and SeeYou.

[edraven]

Is there a way to specify absolute in the .kml? It's a bit confusing if you want to send the .kml to someone and have to explain to them to right click and choose absolute before it will work

[ink_polaroid]

In the <Point> tag, put <altitudeMode>absolute</altitudeMode>, instead of <altitudeMode>clampedToGround</altitudeMode>

[triphazard]

I'm a Hang Glider pilot so I played with track logs in GE as soon as I could. There was a bug at first, but a later beta fixed it.
I use a GPS that records altitude (Garmin 76S). Not all do. If you use an older GPS, you'll not be able to plot your flight through the air.
I use G7towin.exe to download the tracklog from the GPS and then save it off in any of several formats. For GE, I save a GPX file.
When I import that GPX file into GE, I get the altitude info in the resulting placemark files. By changing the properties of the folder (top of the branch) to Absolute, from Clamped to Ground, I get the tracklog points up in the air at the altitude they should be. This seems to be the problem in the other posts here, but I'm not having that problem at all. BTW, while editing that parent placemark, I also change the icon from the custom one (where does that come from?) to a small one and I change the icon size from 1 to .1.

The problem that I AM having is getting my tracklog to stay in its proper place when I angle the view. For example, when viewing from directly overhead, I see my tracklog following a ridgeline. As I angle the view down, the tracklog slips so that it looks like it is halfway down the ridge instead of appearing over the ridge. I think it was mentioned elsewhere on this bbs that it looks like the earth-center for the tracklog is different than for the earth surface directly under the tracklog. The two seem to rotate around a different center. I'm hoping that this problem will be overcome.

I've attached a .gpx file that should display properly, after you edit the resulting "GPS device" placemark.
- save the file to disk
- change the file extension from .kml to .gpx (this bbs won't let me attach a .gpx file)
- open it from GE

Ernie

[triphazard]

Oops. I take my previous post back. I just tried the attachment with my current ver. of GE+ (3.0.0336beta) and it doesn't work like it did in the earlier beta. In that earlier beta, opening the .gpx file gave me a placemark branch like this:
-gps device
--waypoints
--tracks
---(a folder with no name)
----(a waypoint for each trackpoint)
--routes
With this curr. ver of GE I get the same layout except for the tracks:
--tracks
---(folder with no name)
---- points
-----(a placemark for each tracklog point)
---- path (a single Path placemark)

And both the points and path have the altitude set to 0. No altitude.

So it seems that there is a bug in this version.

BTW, I love having both the points and the path. Once the altitude is working, I can keep the path on the ground and the points up in the air.

I'm attaching the placemark branch from the earlier ver. of GE so you can compare. It saved off as a kmz file.

Ernie

[seer]

...over here to get the fame it justly deserves.

[number1fan]

You all be safe flying those rigs!

Lost a good friend in 1991.....