GPS Information: Track Points and The 500 Point Limit

For those who don’t know much or anything about track “points”, here is a little overview of that – whenever you turn your GPS on it starts recording what use to be called “bread crumbs” to record where you have been. These are now called “track points”. A track point is recorded at different intervals, depending on how your unit is configured. It could be every 5 feet or every 5 seconds or whatever. The track point history can be used in many ways, one of the most vital is getting you back the way you came if you get lost or just confused – this is normally called “back tracking”. What I use them for is to record my hiking/boating history. When I get back from a trip, I download this and my waypoint data to my computer and save it for later trips. Now most all GPS software and GPS units display the points, but they also connect the points so that you see lines and can better determine your path. The thing to remember is that there are only “points”; the lines are just displayed for your viewing. Now comes a problem with certain GPS units, they can store up to 10,000 points for recording, but only allow 500 points to reloaded to the unit. Now this is strange and is a problem with certain Garmin units for sure. What that means is that if you took a hike that consisted of 2200 points and when you got home downloaded that to your software, that would be fine. The 2200 points would be downloaded and stored for viewing and possible later use. Well, the day comes you want to use it; you upload it to your Garmin unit. Low and behold only the first 500 points of the 2200 actually are loaded to your unit. That would mean that only a portion of the hike would be available, the rest would be lost. Some software would have warned you of this problem, while others would just let you find out when you got to the end of the 500 points. What can you do about this problem? I suggest first, make sure it is a problem with your GPS, read the manual or ask. If it is not a problem, that is great, if is a problem, here are some solutions –
1. You could download and install a program "GPX Track Splitter" from this website http://sites.google.com/site/gpxtracksplitter/ (look at attachments section - bottom of page). It is a pretty simple program which does not have any means to simply install it, you have to place it in a folder to be used. It is a very nice program, which does the trick – just not that user friendly. You will also have to insure that the tracks you want to split are stored in a file using “GPX" format. GPX format (GPS Exchange Format) is a data format for the interchange of GPS data (waypoints, routes, and tracks) between applications and Web services on the Internet. When done running this program, you will have a new GPX file which will have your tracks split into segments of 500 or less points, which will now work in any GPS
2. If you have a Garmin unit and have their program called “Mapsource” loaded on you computer, you can what they call “filter” a large number of points into a smaller set. What this actually does is to remove points that it thinks are not necessary. I’m not sure how good this is because it would I suspect remove some of the bends in say a windy trail. But they have it, so hopefully it works! Just start Mapsource, load the tracks you want to “filter”, right click on the tracks and select “Track Properties” and then click on “Filter” – select the option you want (no more than 500 points) and select “OK”. You can now load this to your GPS.
3. Other software will allow you to do basically the same thing as Mapsource about, but they call it “simplify” tracks. This means again that they will take a large number of points and try and reduce them using some kind of algorithm. I don’t have a lot of faith in this method, but they are there and that is what they do. There is one other situation this all comes into play, that is when you want to download other users tracks from websites so you can follow their route. I know that two of the major ones as of this writing handle the problem of a large number of tracks in different ways – WIKILOC – This website allows you to select the option of splitting a large number of track points into small segments. This will take care of everything. Most GPSs can handle multiple segments without any problems. Using this method you will get all the track points as they were uploaded. EVERYTRAIL – This website seems to reduce all uploaded tracks down to 200 track points. This will eliminate the 500 point problem, but it I’m not sure of how well it will reflect a windy trail.

It is up to you to determine what your GPS unit can support. I suggest you look at your manual and also use “Google” to learn more about this subject. See my write-up on using WIKILOC downloaded tracks and waypoints for some more ideas.

Track Line as Seen in Google Earth (click on picture to enlarge)