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IDProjectCategoryView StatusLast Update
0000914GeoSetterImage Datapublic2012-10-08 23:30
Reportertakeru Assigned ToFriedemann  
Status assignedResolutionopen 
Product Version3.4.23 beta 
Target VersionFixed in Version 
Summary0000914: incomplete GPS mapping by Holux M241
DescriptionFirstly, I appreciate so much about your contribution on developing such a useful software in public.

Since sometime in the last year, I noticed that Geosetter got unble to map the most of the images with GPS log data by my Holux M241 (both of a native .trl and .kml), even when accomplished point data were acctualy logged.

Trying to convert log data into .gpx data, Geosetter becomes able to match the data.

Sample GPS data are attached, and images in a time stamp, e.g. 17:01 JST(UTC+9) on the 25th Jan 2012, cannot be matched by Geosetter.

The problem is consistent among all PCs I have, so it is less likely to be an configuration corruption by a specific PC.

I have been rolled up my Geosetter up to 3.4.22 beta, the problem remains.
My GPS Babel is in
TagsNo tags attached.


2012-01-26 10:54


geoLogs.2012.01.25.ZIP (7,630 bytes)


2012-03-16 11:53

reporter   ~0001734

Last edited: 2012-03-16 11:54

Ich kann die Probleme mit den Holux-M241-Tracks nur bestätigen (.trl und .kml).
Man bekommt beim Laden der Dateien die Fehlermeldung, dass die Tracks keine Zeitinformationen beinhalten (was natürlich nicht stimmt). Ich habe den Fehler erst bei mir gesucht und lange probiert, bis ich (glücklicherweise) hier im Forum gefunden habe, dass ich wohl offenbar nicht der Einzige bin.
Der Workaround über das Konvertieren in eine .gpx-Datei funktioniert Gott sei Dank! Ist aber sehr zeitaufwändig, wenn man sehr viele .trl-Dateien besitzt, da man diese nur einzeln konvertieren kann (mit dem Holux-Utility).
Ich hatte mich schon sehr gefreut, dass man die .trl-Dateien mit Geosetter direkt verwenden kann!
Wäre schön, wenn der Fehler in der nächsten Version behoben wäre.
Vielen Dank!


2012-05-01 21:19

reporter   ~0001768

Last edited: 2012-05-01 22:56

[corrected to describe parity byte]

The Holux TRL binary files come in two formats, depending on your device's firmware version. There used to be web pages describing this, but it seems like the English links may have gone stale. So here is what I have found.
The file format uses a little endian (Intel) convention.

For firmware versions 1.12 and older, the binary format was a 16-byte record as:

[bytes 00-03] unix epoch time (uint32)
[bytes 04-07] latitude (float32)
[bytes 08-11] longitude (32-bit float)
[bytes 12-14] altitude in meters (*1)
[byte 15] parity byte (XOR even parity *2)

For firmware 1.13, a speed field (m/s) was added, making a 20-byte record as follows:
[bytes 0- 3] unix epoch time (uint32)
[bytes 4- 7] latitude (float32)
[bytes 8-11] longitude (float32)
[bytes 12-14] altitude in meters (*1)
[byte 15] parity byte (XOR even parity *2)
[bytes 16-19] speed (m/s) (float32)

 (*1) This field is a 24-bit floating point number (an ieee-754 with the least significant bits of the mantissa omitted). The most significant bit of byte 14 is the most significant bit of the floating point number (the sign bit).

One way to decode this field is to read bytes 12-15 as a little endian integer, then shift up by 8 bits.

(*2) The parity byte is such that XORing all the bytes in the record will result in 0 (even parity)

In my personal processing, I autodetect between the two formats by attempting to decode the data as each format, then seeing which one produces data with the most lat/long values that are within +-90/+-180 degrees. This seems to work pretty well. Some additional checks could be checking for appropriate file length, and checking that the timestamps increase by a small amount each record.

I am attaching logs demonstrating tracks in each of the two firmware versions, along with KML files to allow you to unambigously verify the data.

See also:

2012-05-01 21:20 (32,978 bytes)


2012-09-09 10:45

reporter   ~0001839

Last edited: 2012-09-09 11:06

Please try my new GPSBable-Version with fixes for Holux TRL-files. I hope it solve the problem. Please report


I am sorry but I can't read this chinees or japaneese web page.

I've tested the files from the atteched TRL-Files and it works. See speed in the hardcopy "Holux-TRL-Test.jpg"

2012-09-09 11:08


Holux-TRL-Test.jpg (219,330 bytes)
Holux-TRL-Test.jpg (219,330 bytes)


2012-10-06 07:42

reporter   ~0001862

I also have had problems with retrieving good data from my Holux M-241. In my case, the retrieved files, even after a day's logging, were only about 5K and consisted of the beginning and ending waypoints and perhaps one or two intermediate ones. The solution that works for me is to have the appropriate Silicon Labs USB driver(eg, the correct one for Win 7) but to roll the logger utility back to the one that came with the logger, v1.1.0.46 rather than the latest version (v1.1.0.48). That combination seems always to work flawlessly with Geosetter.

Hope that helps.

Erik Krause

2012-10-08 23:30

reporter   ~0001864

I use GPSBabel (GUI) exclusively to read directly from the M-241 and write GPX files containing all tracks. No need to use crappy Holux utility and proprietary TRL file format.

Issue History

Date Modified Username Field Change
2012-01-26 10:54 takeru New Issue
2012-01-26 10:54 takeru File Added: geoLogs.2012.01.25.ZIP
2012-02-26 01:37 Friedemann Status new => assigned
2012-02-26 01:37 Friedemann Assigned To => Friedemann
2012-03-16 11:53 Pai Note Added: 0001734
2012-03-16 11:54 Pai Note Edited: 0001734
2012-05-01 21:19 cryptor3 Note Added: 0001768
2012-05-01 21:20 cryptor3 File Added:
2012-05-01 22:56 cryptor3 Note Edited: 0001768
2012-09-09 10:45 twoface Note Added: 0001839
2012-09-09 11:06 twoface Note Edited: 0001839
2012-09-09 11:08 twoface File Added: Holux-TRL-Test.jpg
2012-10-06 07:42 suttonbg Note Added: 0001862
2012-10-08 23:30 Erik Krause Note Added: 0001864