March 12, 2010
GPX to CRS - Setting a Course in your Forerunner
A plan was hatched to meet up with a fellow runner who needs to pound out 18 miles this weekend, like myself. The idea came up to preview the Wisconsin Marathon course in Kenosha, since he'll be running it as his first marathon in a few weeks (5/1 - go cheer! I'll be down in Champaign). It turned out that the marathon route was nicely posted on MapMyRun.com. It's a complicated route neither of us have run before. Since we both have Garmin Forerunner GPS running watches, we figured we'd let them be our guide, and rather than try to re-map it by hand whittled down to 18 miles, I decided to try futzing with the downloads available. They provide the option to download as a Garmin .crs file, but since I wanted to edit the route, I opted for the more universal .gpx file.
One note on Garmin Forerunner Courses, I have NOT used Courses a lot. About a year ago, I built a Course similarly for a 20-or-so-miler once, and the watch got VERY picky about hitting the points, going off-course, and not advancing properly through the points. I BELIEVE this was a flaw in my source Course - I'd made it too sloppily (not following slight bends in mostly straight roads, not putting in enough points around arcs, etc. Keep this in mind when editing/building a source track, and don't use it for life-or-death navigation until you test it out and see how it works FOR YOU.
Continuing on, I opened the .gpx in a handy old program I have called ExpertGPS from TopoGrafix. It's not the prettiest program out there, but if you look at my old flying tracklogs, it's a workhorse when it comes to GPS data. Other than address-based routing, I've always preferred it for to the Garmin-specific software for working with Waypoints and Tracks.
As I said, the marathon route itself is very complex. It turns back on itself several times, so cutting out that redundancy (with the zoom and scissor tools) got me down to about 20 miles. One thing ExpertGPS wonderfully is that it easily reverses tracks and joins two together. So I cut out the repeat areas, deleted as needed, and then re-joined the resultant fragments into one track. To lose the the extra two miles, I busted out the scissors again and just started snipping off bits of the northern out-and-back section until I was near 18 miles - re-joining the main parts again when done.
One final tweak I did was to adjust the start and finish location to be less ceremonial (on a loop out by Lake Michigan) and closer to a parking lot. The 'Draw Track" tool has a nice feature which lets you extend an existing track, so that was trivial.
Once all of the edits were done, I saved the file back to a new .gpx file.
Garmin's Training Center Software (used with Forerunner GPS watches and the like) lets you import Courses which can guide you through a workout, but amazingly, it doesn't import the nearly universal GPX format. So a translator is needed to get the .gpx file into a .crs file Garmin Training Center can use. There are a few options to do this.
One option is the handy website GPSies. The upload form will take a local file, data directly off a Garmin GPS, or the URL to a file anywhere on the public web. There are many options as far as what to convert the data to, but for the Forerunner you want to select, from the Track pull-down, "Garmin Course CRS." If you click "Show Options," you can reduce the number of points in the track (to make a smaller, less-detailed file), give the track a name (this will be handy when you import it to the Training Center and watch), speed (if you like dot-racing the dude on your watch), reversing the track, using a special algorithm for reducing the track further, or Add / replace elevation. I'm not totally up on that option, but it sounds good to me (to get an elevation profile on the watch as opposed to the Course just showing flat), but it's not critical. Once you click convert, the browser will churn a bit and eventually spit out a File dialog and likely ask you if you want to open or save the resultant file. Save it (make sure it gets a .crs extension).
Another other option is to use a stand-alone converter program. There are several out there and Google can guide you, but I found/used (right-click/ Save-As) gpx2crs.exe (a href="http://www.niniu.com/Garmin/release%20notes.txt">Release Notes) I don't know anything about the author, hosting site, or anything. I smelled it and it didn't smell rotten, but use it (as all software randomly downloaded from the internet) at your own peril. The interface is pretty simple. Stay on the first tab "Convert GPX to Course," browse to the source .gpx file, put a target pace and make sure "Simulate an average speed of" is selected (default), add extra points or reverse the track if that's your thing, and click convert. At that point, you'll get prompted for a filename/location. Again, ensure the .crs file extension is added. I noticed that when the conversion is done, the progress bar is still colorized like it might be doing something. It's likely not. The 18 mile track I was working with only took a second or two to process on an old laptop.
Once you have your .crs file, you can open the Garmin Training Center software. Click File, Import, Courses. Browse to your newly created .crs file. and you should see the new course listed when you press the "Courses" button at the top of the Training Center. You might have to expand one or more folders to find it. gpx2crs gives the course a non-unique name, so it's a good idea to right-click the new course, select Edit, and give it a good name - in this case, "Kenosha 18."
The next time you sync to your watch, the new Course(s) should go along for the ride. To use a Course on your run, cycle through the Modes on the watch, select Workouts, then Courses (this is from memory - might not be exact). When you select a Course, you can edit it (just the name), delete, or "Do Course." Once you select that, the watch will guide you to the start point, and you're off.
BTW, I'm NOT going to get to test this out this weekend, as timing didn't work out, but we might do similar with a 20-miler in a couple weeks. I'll try to remember to post back with results.
Yeah, I should have included some screenshots in this. Oh well.
Edits/comments/suggestions are welcome @ eblo @ ratula dot net.
Happy running/navigating!Posted by oblivion at March 12, 2010 01:53 PM