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Making Track Logs on your GPS #3715
Back To Discussion List Written: 2011.06.07 by: Robin Tivy

I now use "Track Logs" as a means of capturing the waypoints I use in bivouac trip reports and trail records. As you know, when you turn on "Track Logging" the GPS automatically marks the points every so often. So you just turn the GPS on at the start of the trip, put it in your pocket, and at the end can have hundreds of waypoints. So Bivouac now has a parser for Track Logs. In order to end up with a good track log, and save batteries you have to manage your track log collecting. I have gradually worked out a few tricks and procedures over the last few trips, which I wanted to present to you for discussion. So here it is:


  1. Configure GPS Tracklog to Distance not Time
     The default settings on most GPS units is to record a new point every 30 seconds, which results in far too many points in a whole day. What you want is to record points according to distance, not time. Go into Setup..Track Log and set the "Record Method" to "Distance" rather than "Time". Then it asks for the distance interval. I set my distance interval to record a new point only every 100 meters. That gives you a much more manageable track log. Eg: A 10 km daytrip would have 100 track points, which is plenty.

  2. Don't turn track log on until you start the trip. This allows me to use the GPS while driving for road junctions, etc. When I finally turn on the track log, it is in "Setup..Track Log". Change it from "Do Not Record" to "Record and Show on Map". From then on, every time I look at the map on the GPS, I see the black line for the track log.

  3. Turn off GPS when stopped
     Every time you stop for a lengthy period, turn off the GPS. (To save batteries). When you turn it back on, it will resume adding points to the same track log.

  4. Key Sections Only
     During the day, turn the GPS off for long sections you could reconstruct from a map. Eg: If you plan to follow a ridge crest for a couple of hours, you may as well turn of the GPS. This saves batteries. When you turn it back on, more points will be added to the same "current track" as before. There will just be a straight line from the point where you last turned the GPS off to your new location (which you can enhance later from the map). Using this "key sections only" strategy could mean you could capture 3 or 4 days track log on a single set of batteries. (On my Garmin Oregon, I only get 12 hours or so from a set of batteries).

  5. Save Current Track Log at Destination:
     When reaching the main destination, go into the track manager and save the "current track" as some filename. Eg: Grouty. That prevents more garbage from being added to your track if you happen to turn on the GPS for some other reason later. On the Grouty trip, I forgot to terminate the track log, and ended up with a bunch of garbage at the end of the log going half way down the Hurley road to Lillooet. Of course one can always get rid of this garbage by hunting thru the .gpx file, but may as well not have it to begin.

  6. Export Track Log separately from Marked Waypoints
     Even though I use a track log, I still specifically "mark" some key waypoints, because I can then write down corresponding notes in my black book. So when I get home, my GPS has 8 or 10 waypoints, plus one or more named track logs. Since the bivouac waypoint parser is different from the bivouac track log parser, I've found it easiest to export each one separately. Eg: I plug my Garmin GPS into the computer, start up "Basecamp" program, then copy and paste one track log to "My Collection", then export "my Collection" to a file on my computer. Then I parse that .gpx file. Then I go back into the GPS to get the individual waypoints. I erase My Collection, then cut and paste the group of 10 waypoints, then go through the export step again. Although you can export both tracks and waypoints in one .gpx file, the Bivouac parsers won't know what to do or how to splice in the waypoints.

  7. Label key points such as camps
     The output of the Bivouac track log parser is just a huge list of points, and every one is marked as a "cp" (control point). So to make the topomap look good with your report, go through the waypoint list and find your camp, the summit, etc. You can cause them to be labelled on your topomap by erasing the "cp" and putting a name into the waypoint, marked by an asterisk. For example, *Camp1 (See the Grouty Trip)

  2011.06.06 - Grouty-Mortar Ski Trip In this trip, my basic plan was to have a partial track log, plus manually "mark" a few key waypoints. To save batteries, I started out with the track log turned Off. I turned on the GPS and marked the spot where we camped, without it being in the track log. I turned my GPS on only at the point where we left the Hurley road, and left it on till we got to camp. I had the track log configured to take one point every 100m. (Which is plenty of points, and next time, I'll do one point every 200m, to make things easier.).

I turned off the GPS when we got to camp, and then turned it on again when we went out for an excursion. Note that it just adds onto the same track log. Next day, I turned it on again, then turned it off when I got to Mortar peak and left it off for the next 1.5 km to Grouty. I did this to save batteries, since I knew I would be exactly on the crest of the ridge all the way, and could reconstruct it from the map.

I only recorded points on the outbound trip, since I only plan to have one line on the map in my trip report. Again to save batteries.

At the summit, while Steve and I played around with the GPS units to get the height of the peak, somehow it resulted in about a dozen identical points in the track log. Probably everytime I turned the GPS off and on, to get a new height estimate. I later erased these duplicates in my trip report waypoints. So I suppose it pays to look at your final waypoints and make sure there are not a lot of duplicates.


#1536 - 2011.06.08 Steve Grant - To add to Robin's article...
If the gps track logging is set for distance (or even time), and you forget to shut it off when you get back to the car, it will record innumerable points on the drive home, fill up the memory, and start deleting the oldest ones. The oldest ones, of course, are the important ones.

Setting the point distance to 200m may limit the value of the track for following/backtracking where accuracy is needed. Such as in a whiteout on a crevassed glacier, following a trail intermittently buried by snow, or on complex, fog-shrouded peaks.

Another reason to shut off the gps while you're stopped while creating a track, is that the gps "wanders" when it is not moving. These position recalcuations appear to the track logging as movement, and you can end up with a rat's nest of tangled segments. It will also do this if you repeatedly turn the gps on and off while stopped. The redundant points can be edited out later, but it's better not to record them to begin with.

When I save a track, my Garmin Etrex Hcx asks me if I want to save the entire track. If I answer yes, it adds to the track points from other trips and segments hundreds of km's long, which have to be edited out later.

#1535 - 2011.06.08 Sandra McGuinness - An alternative to using a GPS
Another way to get GPS waypoints for your Bivouac reports is to use some kind of mapping software - I use Memory Map, but I suspect that half a dozen other programs would work as well. If you are like me, and don't use a GPS but navigate by terrain features and/or a compass, you pretty much know where you are all the time and it is a simple matter to create a route of your trip using whatever mapping package you have when you return home.

With Memory Map, you simply select "route" and then click the map at whatever locations are appropriate to create a GPS route. I save this route as a "maptech terrain route" (.rxf) and use the digitizer menu to convert the waypoints produced into Bivouac waypoints. Any word processor or text editor will allow you to open the rxf file and copy it into the Bivouac parser. All the waypoints come out labeled "cp", but it's easy to relabel the crucial ones so that they appear on the topo map.

This method has three added advantages namely, you don't need to lug around a GPS, or piss off your friends by standing around for hours dicking about with the little screen when it is perfectly obvious where you are, oh, and you save on batteries.