GPS exchange format, or GPX, is an open GPS data format, which can be used to describe waypoints, tracks and routes. When you mark a waypoint into your Garmin (or some other brand) GPS device, the information is saved in the form of GPX file. However, typing any significant information into to the GPS in the middle of nowhere can be a major pain in the rear end. GPX files are also the information sharing tool for the Geocaching community. Geocachers usually get their ready made GPX files directly from their official hobby sites, such as geocaching.com, and those sites are doing their job pretty well, but whether you are a geocacher or not, every now and then it would be nice to be able to conveniently add some extra info with the symbol marking your geocache or any waypoint of interest. After years of wondering what the hell can be so significant or interesting that I have bothered to mark it into my GPS with a name “a”, “1”, “abc”, or in the best case, a descriptive word, such as “camp”, I have begun to modify my GPX files at home.
During any random hikes in the forest, I mark any points of interest into my Garmin, using the shortest possible name for each spot, usually a running number. I also type something into the “notes” area, usually a single letter or number (this saves some typing work down the road). Similarly, if I already know which Garmin symbol I want to use instead of the cursed standard flag, choosing it is behind a single click in the field. After returning home, all of the spots still clearly in my mind, I connect my Garmin to my computer, and, in front of a fire place, possibly with a glass of wine, type a proper description for each of the spots with a proper keyboard, and the next time, approaching the symbol on my Garmin device, instead of wondering what the f does this “a” mean, I can read something like “a nice spot for a coffee, not enough fire wood for over nigh camping” or “Aggressive farmer, owns a shotgun. Uses small shots, though.”.
Well, how to do this?
After connecting the GPS device with the computer, open the Garmin folder. In the Garmin folder, there is another folder with the title GPX. Open it, and in there you should see a bunch of files named something like “Waypoint_01-OCT-16.gpx”. Pick the date of your trip, and open the file. At the last couple of lines of text, you should see the name you gave to that particular point of interest in the form of <name>the name you gave</name>. Now you can replace the “the name you gave” with any new name you wish. Similarly, you will see the single letter “note” you typed in the form of <cmt>your note</cmt> (If you did not add any notes to the original waypoint, this <cmt>your note</cmt> does not exist in your gpx file, and you must manually add “<cmt></cmt>“ between “</name>”, and “<sym>” markings in the gpx file). Replace “your note” with a proper description for your point of interest. And, if you wish to change the symbol now, replace the “Flag, Blue” with the symbol of your choice (below this text, you can find some of the symbol names. Finding the rest of them requires some google activity, or some fiddling with your GPS.) Then just click “save as”, and rename your gpx file appropriately.
(If your text editor tries to save your file as xxxxx.txt, change .txt to .gpx)
Then just disconnect your GPS from the computer. Next time you open the map in your GPS, move the cursor on to now properly named symbol, and click it. And now, instead of no, or vague description of the place, you will see the information you just typed to the “your note” section of the GPX file.
That was probably the simplest and easiest way to customize GPX files. However, sometimes it would be nice to be able to prepare GPX files at home in advance, without separately visiting every single point of interest, and unfortunately, the entry level GPS devices, such as Garmin eTrex 10, only let you mark waypoints at your current location. To get around this problem, it is necessary to replace the coordinate values of an existing GPX file with the values pointing to your place of interest. It is possible to get the coordinates from pretty much any map program such as Google maps, Openstreetmaps, or even from decent paper maps, but a common problem with many of these outside sources is that they use different coordinate systems than your GPS device.
Sometime in the future, I may make a video about coordinate conversions, but for now, I’ll only describe a quick and simple way to utilize your own GPS device to get the correct coordinates for your GPX file.
In order to see GPX compatible coordinates on the map, turn on your GPS, and click “Setup”. Then scroll down, and click “Position format”, and choose hddd.dddddo (my default was UTM UPS). Now open the map in your GPS, move the arrow to the spot you wish to mark, and read the coordinates from the screen (if you need the elevation of the spot, zoom in, place the arrow on to the nearest contour line, and read the elevation). Next, open a random GPX file (I have one named “template.gpx”), and replace the (lat=”XX.XXXXXX”, lon=”YY.YYYYYY”, and <ele>ZZZ.ZZZZZZ</ele>) with your new latitude, longitude, and elevation values. As you may notice at this point, the default values of Garmin’s waypoint GPX files have six decimals, and you only got five decimals from the screen of your GPS. Don’t worry about that at all; The accuracy of your GPS device with five decimal coordinate values is about 1 meter (3 to 4 ft), which, for a civilian in any imaginable situation, is quite enough. (the default 6 decimal system probably has something to do with Garmin’s preparation for the future.) Now that you have the correct coordinates, do the renaming, redescription, resymboling, and save the brand new file to your GPX-archive folder, from where you can copy it to your GPS at your convenience.
GPX files are small (about 1 kb), and therefore, easy to store and transfer. I store my personal GPX files in the hard drive of my computer, and when ever changing the maps in my GPS, I also replace the old GPX files with the corresponding new ones. In addition, when ever in need of changing information with the friends, who are, for example, going to hike alone in my home grounds, it is extremely quick and easy just to e-mail them all of the necessary gpx files from the area, and after a minute or two of work, they have all of the nice secret camp sites, fresh water sources, and such, in their own GPS devices.
Some useful Garmin Waypoint Symbol Names:
- Drinking Water
- Bike Trail
- Fishing Area
- Boat Ramp
- Gas Station
- Medical Facility
- Danger Area
- Restricted Area
- Picnic Area
- Scenic Area
- Pin, Blue
- Skull and Crossbones
- Police Station
- Radio Beacon
- Swimming Area
- Trail Head