Garmin & Google Earth GPS Logging Tutorial

Part of the GPS logging project

This tutorial will teach you how to record route data on Garmin devices and map it with Google Earth.

Record GPS Routes with Your Garmin

I wrote this tutorial using a Garmin nüvi 2539LMT. However, I’ve had success using the same steps with other variations of the Garmin nüvi.

Fortunately, the nüvi already records location data in GPX format by default; all you have to do is get it off the device. To extract them, we need to hook up the nüvi to a computer via USB – the same way you’d hook it up to install map updates. The nüvi should have come with its own USB cable, but any standard USB cable should work – plug it into the same slot into which you’d normally connect the power cord. The nüvi 2539 takes a USB Mini cable.

Garmin nüvi 2539LMT connected to a PC via USB

Your computer should recognize the nüvi as a USB storage device and mount it. On Windows 10, it will be listed in This PC.

Screenshot of Windows Explorer

Navigate to the nüvi’s /GPX folder. (On some models, this may be in /Internal Storage/GPX.)

Screenshot of Windows Explorer

Copy Current.gpx to your desktop, or somewhere else on your computer where you can find it easily.

Make sure you use copy instead of cut, and do not delete or modify this file (or any other file) on the device. The nüvi is very particular about the integrity of its internal files, even if you later copy them back onto the device – I’ve lost my favorites on more than one occasion from this. Copying files is fine, but to be safe, treat the nüvi like it’s read only and don’t change anything on the device.

Current.gpx contains the most recent route history tracks, as well as all locations you’ve saved in the device. The device will try to keep the file to about 2 MB; if it goes above that, the oldest tracks are placed into .gpx files in the /GPX/Archive folder. Using the GPS daily, 2 MB equated to approximately two weeks of driving under normal use. Longer road trips fill it up quicker, so if you don’t want to deal with the archives, I’d recommend copying the Current.gpx file to a computer at the end of each day of driving.

Trim Extra Data

Since the Garmin GPX file contains the last 2 MB of data, it’s possible that it contains more location history than you actually want to map. If that’s the case, you’ll need to delete the extra GPS tracks with a GPX editor.

On Windows, I use EasyGPS as a free way to edit GPX files. (On MacOS, I haven’t been able to find a good solution for free, but myTracks has a free trial.)

In EasyGPS, select Tracks from the dropdown at the top of the lower left panel, and you’ll see a list of tracks named by date. By looking at the dates, you should be able to tell which tracks you don’t need, but if you’re unsure, you can double click a track to preview it and figure out if you need it.

Screenshot of EasyGPS

Delete a track by selecting it and pressing the DEL key (or right clicking on it and selecting Delete Track).

Once you’ve made any necessary deletions, save and close the GPX file.

Convert the GPX File to KML

You now have your map data in GPX format, but Google Earth uses Keyhole Markup Language (.kml or .kmz files) to show map annotations; it can’t use .gpx directly. Fortunately, free converters exist; I use GPS Visualizer.

Screenshot of GPS Visualizer

On the right side of the page, click the Google Earth KML link. This brings you to the following form:

Screenshot of GPS Visualizer

On the upper right, browse to where you saved your Current.gpx file. Generally, I change the Colorize by: option to None so that all tracks end up the same color. The defaults for the rest of the options work well.

When you’re done, click the Create KML file button. This will create a .kmz file which you can download to your computer.

Import the Location Data into Google Earth

Simply open the .kmz file with Google Earth, and you’re ready to go!

Screenshot of GPS Visualizer
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