I am planning on doing the Antelope Peak Challenge this year, and in preparation, I have been getting my GPS up and running with the tracks. In doing so, I’ve had to do some converting and manipulating to get the tracks how I want them on my gps, and so I decided that others may benefit from the file-wrangling I’ve done.

First things first, I like to use Google Earth to visualize routes and get an idea of general route directions. So, I have converted the main file to .kml format for easy viewing in google earth

Antelope Peak Challenge – v2 – 24OP bonus lap.kml

Since I have a Garmin eTrex Vista Cx there is a limit to 500 points you can load into a single ‘track’ file. The guys at AES were kind enough to split it into 500 point chunks. Unfortunately, that means that there are 11 tracks now on my GPS. What a pain.

Fortunately, GPSBabel has a handy-dandy optimization feature that lets you simplify a track based on interpolation to however many points you want. So, here is all of the APC, in a single 500-point track, .gpx format

APC - Simplified 500 pts 1 track.gpx

Finally, if you would like to compare that to the original via google earth to see how much it ‘straightened out’ the track to pare it down to 500 points, here is a .kml version of it.

APC - Simplified 500 pts 1 track.kml

I couldn’t notice any major differences, except some jagged edges on some switchbacks. And on the bright side, the roads on the way out and back now consist of 2 points each, not 100 in a straight line. If you have any problems with them, or questions about how I did it, feel free to let me know via email at nathan (at) 3dmobility (dot) com.

Edit: Here is a picture of what I would consider the ‘worst’ simplication. This screenshot (from google earth) is about 1 mile across, and about 1/2 mile tall. Still very usable.

Edit #2: I used a simplified track on the singleswizzle this past weekend, and although it worked just fine, I can see the benefit of having the whole track. I still think this is a good way to optimize files if you have a lot of tracks on your unit and need to combine some of them. To each his own. It was a good experiment, and I’m glad I worked out how to do it.