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Author Topic:   Converting Lowrance .usr files to .gpx
SJH posted 06-08-2011 03:17 PM ET (US)   Profile for SJH   Send Email to SJH  
I have a HDS-5 unit and have had it on the water couple of times now. When I purchased the [Lowrance HDS-5], I converted my Garmin waypoints to GPX format files, loaded [the GPX files] on an [SD] memory [card] and loaded it into the HDS-5. [The transfer process] worked great. Now, what do I need to transfer my Lowrance .usr saved files to GPX?


Chuck Tribolet posted 06-08-2011 04:45 PM ET (US)     Profile for Chuck Tribolet  Send Email to Chuck Tribolet     
jimh posted 06-08-2011 08:06 PM ET (US)     Profile for jimh  Send Email to jimh     
If the .USR files are on the HDS-7, I believe you can just save them as .GPX format files using the HDS-7 itself.

The GPX file format is the lingua franca of geo-location file formats.

SJH posted 06-09-2011 01:05 PM ET (US)     Profile for SJH  Send Email to SJH     
My mistake was [exporting] the usr file as a version 4 file. It turns out the GPSBable doesn't support V4. After turning my HDS5 back on, I saw that the data could be [exported] as usr V2, V3, V4, and as a GPX file.

Thanks guys.


jimh posted 10-15-2011 10:22 AM ET (US)     Profile for jimh  Send Email to jimh     
When converting native Lowrance HDS waypoint, routes, and trails for export on the HDS-8, it appears that there is a limit to the size of the data which can be converted to the .GPX format. Based on some recent experience, I saw the HDS-8 operating system crash and reboot during the conversion process when data sets containing trackpoints in very large number (over 20,000) were being exported. After consultation with Lowrance technical support, it was recommended that the export to GPS file format on the HDS-8 be limited to sets of data containing 10,000 track points or less.

Concerning Lowrance's USR format in version 4, Dan Foster of ExpertGPS support is quoted as follows:

In the past, all Lowrance GPS receivers and chartplotters could exchange waypoints, routes, and tracklogs with PC software using their USR file format. Lowrance documented the .usr format, and ExpertGPS was able to read and write these files. With the HDS release, Lowrance still uses .usr files, but writes a completely different, undocumented binary format to the file. They have not released any details on this new USR version 4 file format, and it is complex enough that it cannot be decoded without Lowrance's assistance.

Source: 405354/gonew/1

More on ExpertGPS at

There are several utilities that can work with Lowrance USR data in the version 3 format.

jimh posted 10-15-2011 10:28 AM ET (US)     Profile for jimh  Send Email to jimh     
I don't see any advantage to exporting the files from the HDS in USR version 2 or USR version 3 and then trying to use a utility to convert them to GPX format. Just export the files as GPX files and avoid having to use any added conversion step with a third-party utility.
mydharma posted 12-15-2011 03:51 AM ET (US)     Profile for mydharma  Send Email to mydharma     
A .USR4 to .GPX file converter can be found at
jimh posted 12-15-2011 08:41 AM ET (US)     Profile for jimh  Send Email to jimh     
Thank you for the pointer to the .USR4 to .GPX file converter. The program requires PYTHON to be installed. For MacOS computers, PYTHON is typically already installed. See

For Windows computers, the PYTHON environment must be installed. See

I will take this new application for a test drive soon and report my results. I think I still have some .USR4 files which contain more than 10,000 track points; they should be a good test of the application.

jimh posted 04-28-2012 10:21 AM ET (US)     Profile for jimh  Send Email to jimh     
To update this discussion, I must make mention that a recent Lowrance HDS system software update has cured the problem that I mentioned above with a limitation on the size of the data contained in the waypoint, routes, and trails data export to GPX format from the HDS. There now appears to be no problem in exporting large sets of data to GPX format from the HDS. This problem seems to have been resolved in the software update to V4.1 which was released in February 2012.

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