Track Summary in Basecamp / Fenix / Connect / Oregon

I have a gpx file obtained from a Garmin Oregon about 2 years ago, and It was compressed to remove trackpoints with off track distance less than 4 meters. (taking it from about 4420 points to 1055 points)
Ascent and descent in Meters
Original Track in Basecamp for Windows reads Ascent 782 m Descent 3263 m
This tracks was compressed
When I import the track into Basecamp for Windows, The Elevation Data reads: Ascent 642 m Descent 3123 m
When I transfer the track to a Garmin Fenix and open the Track Details, it reads Ascent 719 m Descent 3202 m
When I upload the track to Garmin Connect it reads Elevation Gain (same as ascent?) 663 m Elevation Loss (same as Descent?) 3143 m
When I transfer the track to a Garmin Oregon 450 and open the Track Details, it reads Ascent 719 m Descent 3202 m (matching the fenix)

Is it considered normal to have such a difference between the Oregon/Fenix and Basecamp/Connect ascent and descent numbers?, do the devices use a different algorithm to calculate this values? and / or elevation corrections?

this is the Garmin Connect Link for the Track:
http://connect.garmin.com/activity/292164504

0 Former Member over 12 years ago

Yeah, as strange as it sounds, this is pretty much normal. It's pretty much impossible to give an exact number for ascent and descent.

Changing the track (compressing it) will impact the results. I believe Garmin Connect actually lays out the track over their own elevation mesh and calculate their own ascent and descent. BaseCamp uses a filter to take out spikes before calculating. I assume the devices use a slightly different filter (but apparently the same one across devices).

Taking all that into account, I am actually pretty happy with how close the numbers are.

Sorry for not being able to give you a more satisfying answer.

0 jbadilla over 12 years ago

Garmin Connect has an option for Elevation Corrections Enabled or Disabled, based on the device having a Barometric Altimeter, I guess the elevation mesh as you say is used if the corrections are enabled.

Talking about the test track. I first exported the uncompressed track with heart rate information from Basecamp, and then Compressed it using another program. When I imported back the following gpx file into Basecamp
https://dl.dropbox.com/u/121839/test.gpx
I get an error Importing the gpx file, I get an Import Problems dialog with the filename, Status Error, Details "Unknown error opening import file"

I had to remove the heart rate information from the file to be able to import it into Basecamp

Can Basecamp check wether the heart rate information in the gpx file is not usable and just use the lat/lon altitude information and load the file anyway?

0 Former Member over 12 years ago

Garmin Connect has an option for Elevation Corrections Enabled or Disabled, based on the device having a Barometric Altimeter, I guess the elevation mesh as you say is used if the corrections are enabled.

Talking about the test track. I first exported the uncompressed track with heart rate information from Basecamp, and then Compressed it using another program. When I imported back the following gpx file into Basecamp
https://dl.dropbox.com/u/121839/test.gpx
I get an error Importing the gpx file, I get an Import Problems dialog with the filename, Status Error, Details "Unknown error opening import file"

I had to remove the heart rate information from the file to be able to import it into Basecamp

Can Basecamp check wether the heart rate information in the gpx file is not usable and just use the lat/lon altitude information and load the file anyway?

BaseCamp will only load valid gpx files. If it's invalid (you can check with validators like http://www.validome.org/xml/) then BaseCamp won't read it. Many third-party programs don't actually write valid XML which is unfortunate.

I ran your file through the validator and it is indeed invalid. The <hr> tag is not allowed at that location.

Note that this validation has nothing to do with Garmin, this is the actual gpx schema that everyone should adhere to.

Link to validation of your file: http://www.validome.org/xml/validate/?lang=en&url=https://dl.dropbox.com/u/121839/test.gpx .