I received my new Locosys GT-31 yesterday. After about half an hour I worked out how to record a track (using TRACK mode). I wasn't sure if the GT-31 could be used successfully in a car, as it was marketed for walkers and surfers, but I found that it worked fine when placed in the space between the sunroof glass and the sliding inner sunroof cover.

When I got home, I uploaded my first track using Navilink II. The data appeared on the PC in several formats including KML and GPX. Just double-clicking on the KML file opened Google Earth and displayed my track, which was extremely satisfying and proved that everything worked! Next I downloaded JOSM and played around with the GPX version of the track, but as this was just a test I didn't upload anything.

At this point I was just capturing data into the GT-31's internal memory. I had bought an SD card, and I knew where the "save to card" option was in the GT-31, but I hadn't figured out how to interpret the data that was saved on it.

Today I took the GT-31 for a walk. This time, I went with the intention of capturing a real track for OSM, so I was careful to follow the footpaths without cutting any corners.

Unlike yesterday, when I settled for using the data from the GT-31's internal memory, today I was determined to work out how to use the SD card data. After all, I had paid for my 2 GB and I wanted to use it. The data on the SD card was in a file whose name ended in "_TRK.BIN". Promisingly, the Navilink II program, supplied with the GT-31, had a "_TRK.BIN" button under the "Misc" tab, but when I used it all I got was an error message: "ERROR_PORT". Normally, ports are what you use to talk to the GT-31, not to the SD card, so this message didn't make sense. Disappointed, I gave up on this approach.

Next, I found a free program called "GPSBabel", which is designed to convert from a multitude of proprietary GPS formats to standard formats like GPX. Unfortunately, this couldn't read my _TRK.BIN file. So, I did some web research and found out that the GT-31 stores data in two places: the track file, and the data logger file. This is probably only true if you switched on the data logger mode in the first place, but fortunately I had done this while I was playing around with the unit yesterday. I managed to get the data logger data onto the SD card by going to the GT-31's "Data Logger" menu and selecting "Save to card". This time, instead of a useless .BIN file, I got a _DLG.SBP file. I remembered seeing "SBP" in the GPSBabel's import menu, so I gave it a go and managed to use GPSBabel to convert the SBP file to GPX. Now I had a file that I could upload to OSM. I did, and it worked perfectly! I used a combination of OSM's built-in editor (Potlatch) and a standalone editor (JOSM) to convert my track into ways, and then, after a delay of a few minutes, my new data appeared beautifully rendered on the main OSM map!

If you managed to read all of this rather breathless account, thank you, and I hope it helps you to contribute to OSM.